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Test: Biology - 11 - NEET MCQ


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90 Questions MCQ Test - Test: Biology - 11

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Test: Biology - 11 - Question 1

Common parasitic protozoans are

Detailed Solution for Test: Biology - 11 - Question 1
Entamoeba causes dysentery, trypanosoma gambiense causes sleeping sickness and giardia is a known as Grand old man of intestine.... all these three are parasitic protozoan in option A elphidium, in option C euglena and in option D Volvox are odd one...
Test: Biology - 11 - Question 2

In five kingdoms of life protozoa are separated from animals and included in kingdom Protista by

Detailed Solution for Test: Biology - 11 - Question 2
Protozoa and the Kingdom Protista
Protozoa are single-celled eukaryotic organisms that have traditionally been classified separately from animals. They are characterized by their ability to move independently and obtain nutrition through a variety of means, such as ingestion, absorption, or photosynthesis.
The classification of organisms into different kingdoms is based on their evolutionary relationships and shared characteristics. Protozoa have been included in the kingdom Protista, which is one of the five kingdoms of life, along with animals, plants, fungi, and bacteria.
Whittaker's Five Kingdom Classification
The classification of organisms into five kingdoms was proposed by Robert Whittaker in 1969. Whittaker's classification was based on several criteria, including cellular organization, mode of nutrition, and reproduction. He recognized that the traditional two-kingdom system of plants and animals was not sufficient to encompass the diversity of life on Earth.
Whittaker's five kingdoms are as follows:
1. Kingdom Monera: Consists of prokaryotic organisms, such as bacteria.
2. Kingdom Protista: Includes eukaryotic organisms that do not fit into the other kingdoms.
3. Kingdom Fungi: Comprises organisms that obtain nutrients through absorption.
4. Kingdom Plantae: Composed of multicellular, photosynthetic organisms.
5. Kingdom Animalia: Contains multicellular, heterotrophic organisms.
Inclusion of Protozoa in Kingdom Protista
Protozoa are included in the kingdom Protista because they possess certain characteristics that differentiate them from animals. These characteristics include:
1. Unicellularity: Protozoa are single-celled organisms, whereas animals are multicellular.
2. Lack of Tissue Differentiation: Protozoa do not possess specialized tissues or organs, unlike animals.
3. Modes of Nutrition: Protozoa exhibit a wide range of nutritional modes, including ingestion, absorption, and photosynthesis, which sets them apart from animals.
Conclusion
In summary, protozoa are separated from animals and included in the kingdom Protista by Robert Whittaker's five kingdom classification system. This classification is based on the recognition of their unicellular nature, lack of tissue differentiation, and diverse modes of nutrition. By placing protozoa in the kingdom Protista, Whittaker aimed to provide a comprehensive classification system that reflects the evolutionary relationships and characteristics of different organisms.
Test: Biology - 11 - Question 3

The less active or motionless food is ingestev by Amoeba as follows by

Detailed Solution for Test: Biology - 11 - Question 3
The less active or motionless food is ingested by Amoeba as follows:
A: Circumvallation:
- Circumvallation is the process in which the Amoeba surrounds the food particle with its body membrane.
- The food particle remains outside the Amoeba's body, trapped within a food vacuole.
- This method is used for larger or more solid food particles that cannot be engulfed directly.
B: Circumfluence:
- Circumfluence is the process in which the Amoeba creates a current of water to bring food particles towards it.
- The Amoeba extends its pseudopodia to create a flow of water around the food particles.
- The food particles are then swept towards the Amoeba's body and engulfed.
C: Import:
- Import is the process in which the Amoeba engulfs the food particle directly.
- The Amoeba forms pseudopodia around the food particle, enclosing it within its body.
- The food particle is then brought inside the Amoeba's body and enclosed in a food vacuole.
D: Invagination:
- Invagination is the process in which the Amoeba folds its cell membrane around the food particle.
- The food particle is trapped within a small pocket formed by the folding of the membrane.
- The pocket is pinched off to form a food vacuole containing the ingested food.
Answer: B - Circumfluence
- The less active or motionless food is ingested by Amoeba through circumfluence.
- Amoeba creates a current of water to bring the food particles towards it, using its pseudopodia.
- The food particles are swept towards the Amoeba's body and engulfed in this process.
Test: Biology - 11 - Question 4
Pernicious malaria is
Detailed Solution for Test: Biology - 11 - Question 4
Pernicious malaria is:
- Pernicious malaria is a severe and life-threatening form of malaria caused by the parasite Plasmodium falciparum.
- It is characterized by rapid onset and progression of symptoms, leading to complications and high mortality rates if left untreated.
- Pernicious malaria is more common in areas with high transmission rates of P. falciparum, such as sub-Saharan Africa.
- It can affect people of all ages, but children and pregnant women are particularly vulnerable to severe complications.
- Symptoms of pernicious malaria include high fever, chills, headache, nausea, vomiting, and muscle aches.
- Complications of pernicious malaria can include severe anemia, organ failure, cerebral malaria (infection of the brain), and respiratory distress.
- Prompt diagnosis and treatment with appropriate antimalarial medications are crucial to prevent complications and reduce mortality.
- Treatment typically involves a combination of antimalarial drugs, such as artemisinin-based combination therapy (ACT).
- Prevention strategies for pernicious malaria include the use of insecticide-treated bed nets, indoor residual spraying, and chemoprophylaxis for travelers to high-risk areas.
Test: Biology - 11 - Question 5
Amoeba cyst is
Detailed Solution for Test: Biology - 11 - Question 5
Amoeba cyst is Three layered
The amoeba cyst, which is the dormant stage of the amoeba, has a three-layered structure. Each layer serves a specific purpose and helps the cyst survive in unfavorable conditions.
The three layers of the amoeba cyst are:
1. Outer Layer: The outermost layer of the cyst is called the ectocyst. It is a protective covering that helps in shielding the cyst from external environmental factors such as temperature changes, chemicals, and desiccation. The ectocyst is made up of a tough proteinaceous material that provides structural support and prevents the cyst from collapsing.
2. Middle Layer: The middle layer is known as the mesocyst. It acts as a barrier and regulates the exchange of substances between the external environment and the innermost layer of the cyst. The mesocyst helps in maintaining osmotic balance and prevents the entry of harmful substances into the cyst.
3. Inner Layer: The innermost layer is called the endocyst. It surrounds the cytoplasm of the amoeba and protects it during the cyst stage. The endocyst is made up of a thin, flexible membrane that allows for the exchange of gases and nutrients. It also contains the nucleus and other essential organelles of the amoeba.
Overall, the three-layered structure of the amoeba cyst ensures its survival and enables it to withstand harsh conditions until favorable conditions for growth and reproduction are available.
Test: Biology - 11 - Question 6

Trypanosomiasis is a disease transmitted by

Detailed Solution for Test: Biology - 11 - Question 6

Introduction:
Trypanosomiasis, also known as sleeping sickness, is a disease caused by the protozoan parasite Trypanosoma spp. It is primarily transmitted to humans and animals by the bite of infected tsetse flies.
Identification of the vector:
Among the given options, the vector responsible for transmitting Trypanosomiasis is Glossina palpalis (also known as the riverine tsetse fly).
Explanation:
Here is a detailed explanation of why Glossina palpalis is the correct answer:
1. Trypanosomiasis is mainly transmitted by tsetse flies, which are found in sub-Saharan Africa.
2. Glossina palpalis is a species of tsetse fly that is known to transmit Trypanosoma brucei gambiense, the parasite responsible for causing the chronic form of sleeping sickness in humans.
3. This species of tsetse fly is adapted to live near rivers and streams, making it commonly found in areas with suitable habitats.
4. Glossina palpalis feeds on the blood of humans and animals, and during its blood meal, it can transmit the Trypanosoma parasite from an infected host to a susceptible host.
5. The transmission of Trypanosoma spp. occurs through the saliva of the tsetse fly, which contains the infective form of the parasite.
Conclusion:
In conclusion, Trypanosomiasis, or sleeping sickness, is primarily transmitted by the Glossina palpalis tsetse fly. It is important to control and prevent the spread of this disease by implementing vector control measures and raising awareness about the risks associated with tsetse fly bites.
Test: Biology - 11 - Question 7
Metakelfin is used in the treatment of
Detailed Solution for Test: Biology - 11 - Question 7
Metakelfin is used in the treatment of Malaria.
Explanation:
- Malaria is a parasitic infection caused by Plasmodium parasites transmitted by the bite of infected female Anopheles mosquitoes.
- Metakelfin, also known as Metakelfin hydrochloride, is a medication used in the treatment of malaria.
- It belongs to the class of antimalarial drugs called 4-aminoquinolines.
- Metakelfin works by interfering with the growth and reproduction of the parasites in the red blood cells, thereby helping to eliminate the infection.
- It is effective against various species of Plasmodium, including Plasmodium falciparum, which is the most deadly species responsible for severe malaria.
- Metakelfin is usually used in combination with other antimalarial drugs to prevent the development of drug resistance.
- The dosage and duration of treatment with Metakelfin depend on the severity of the infection, the type of malaria parasite, and the individual's age and weight.
- Side effects of Metakelfin may include gastrointestinal disturbances, skin reactions, and neurological symptoms in rare cases.
- It is important to take Metakelfin as prescribed by a healthcare professional and complete the full course of treatment to ensure the eradication of the malaria infection.
Test: Biology - 11 - Question 8
Spongilla belongs to class
Detailed Solution for Test: Biology - 11 - Question 8
Spongilla belongs to class Demospongiae.
Detailed explanation:
Spongilla is a genus of freshwater sponges that belong to the phylum Porifera. The phylum Porifera is divided into three main classes: Hyalospongia, Demospongiae, and Hexctinellida.
Here's a detailed explanation of each class:
Hyalospongia:
- This class consists of glass sponges, which are characterized by their silica spicules.
- Glass sponges have a unique skeletal structure made up of intricate glass-like spicules.
Hexctinellida:
- This class consists of the deep-sea or glass sponges.
- Hexctinellida sponges have a skeleton made up of silica spicules, similar to Hyalospongia.
- They are known for their delicate and intricate structure.
Calearea:
- This class consists of calcareous sponges, which have a skeleton made up of calcium carbonate.
- Calcareous sponges are usually found in marine environments.
Demospongiae:
- This is the largest class of sponges, comprising over 90% of all sponge species.
- Demospongiae sponges have a skeleton made up of spongin fibers or silica spicules.
- They are found in a wide range of habitats, including freshwater and marine environments.
Based on the information provided, Spongilla belongs to the class Demospongiae.
Test: Biology - 11 - Question 9

In canal system of sponges prosopyle

Detailed Solution for Test: Biology - 11 - Question 9
Explanation:
The prosopyle is a structure in the canal system of sponges that allows water to flow between the incurrent (incoming) canal and the radial canal. Here is a detailed explanation of why the correct answer is option D:
1. Canal System in Sponges:
- Sponges have a unique water transport system called the canal system.
- The canal system consists of various channels and chambers through which water flows, allowing the sponge to filter nutrients and oxygen from the water.
2. Radial Canal:
- The radial canal is a larger channel that runs through the body of the sponge.
- It is responsible for distributing water throughout the sponge's body.
3. Incurrent Canal:
- The incurrent canal is the channel that brings water into the sponge.
- It is usually located on the periphery of the sponge's body.
4. Prosopyle:
- The prosopyle is a small opening or pore present in the canal system of sponges.
- It acts as a valve or gate that regulates the flow of water between different parts of the canal system.
5. Function of Prosopyle:
- The prosopyle permits water to flow from the incurrent canal to the radial canal.
- It allows water, along with suspended food particles and oxygen, to enter the radial canal for distribution throughout the sponge's body.
6. Answer Option D:
- Option D states that the prosopyle permits water to flow from the incurrent canal to the radial canal, which is the correct answer.
- This means that when water enters the sponge through the incurrent canal, it can pass through the prosopyle and reach the radial canal for further distribution.
In conclusion, the prosopyle in the canal system of sponges is responsible for allowing water to flow from the incurrent canal to the radial canal, and this is why the correct answer is option D.
Test: Biology - 11 - Question 10

Sponges represent the dead end branch of evolutionary tree as they are the only animals to have

Detailed Solution for Test: Biology - 11 - Question 10
Explanation:
The statement claims that sponges represent the dead end branch of the evolutionary tree. To understand why this is the case, we need to examine the characteristics unique to sponges.
Cellular level of organisation:
- Sponges are the only animals that exhibit a cellular level of organization.
- This means that their bodies are composed of individual cells that work together to perform various functions.
- Other animals have tissues, organs, and organ systems, which allows for a higher level of complexity and specialization.
Canal system:
- Sponges have a unique canal system that allows water to flow through their bodies.
- This system helps the sponge filter out small organisms and nutrients from the water.
- Other animals have a more advanced circulatory or respiratory system.
Choanocytes:
- Choanocytes are specialized cells found in sponges.
- They have a collar-like structure that helps them capture food particles from the water.
- Choanocytes are not found in any other animal group.
Sedentary:
- Sponges are typically sessile or sedentary organisms.
- They attach themselves to a substrate and do not move around like other animals.
- This lack of mobility limits their ability to adapt to changing environments or exploit new resources.
Based on these characteristics, it can be concluded that sponges represent a dead end branch in the evolutionary tree. They exhibit a lower level of complexity and specialization compared to other animal groups and have unique features that are not found in any other organisms.
Test: Biology - 11 - Question 11
The neuron of hydra in relation to nerve inpulse conduction
Detailed Solution for Test: Biology - 11 - Question 11
Neuron of Hydra in relation to nerve impulse conduction:
The correct answer is B: Multidirectional.
Explanation:
The neuron of Hydra, a small aquatic animal, exhibits a unique characteristic in relation to nerve impulse conduction. Here is a detailed explanation of why the correct answer is B:
1. Unidirectional conduction:
- Unidirectional conduction refers to the transmission of nerve impulses in a single direction along the length of a neuron.
- In some organisms, such as mammals, nerve impulses travel in one direction only, from the dendrites to the axon terminals.
- However, in the case of Hydra, the nerve impulse conduction is not strictly unidirectional.
2. Multidirectional conduction:
- Hydra is a simple organism with a nerve net rather than a centralized nervous system.
- The nerve net consists of interconnected neurons that allow for multidirectional conduction of nerve impulses.
- Nerve impulses can travel in various directions within the nerve net, facilitating communication between different parts of the organism.
- This multidirectional conduction is essential for coordinating the activities of different regions of the Hydra's body.
3. Polarization:
- Polarization refers to the difference in electrical charge across the cell membrane of a neuron.
- While Hydra neurons do exhibit polarization, it is not a defining characteristic in relation to nerve impulse conduction.
- Polarization plays a role in the generation and propagation of nerve impulses but does not determine the direction of conduction.
4. Non-polarized conduction:
- Non-polarized conduction does not accurately describe the nerve impulse conduction in Hydra.
- All neurons, including those of Hydra, have a resting membrane potential and exhibit polarization.
- Non-polarized conduction implies a lack of electrical difference across the cell membrane, which is not the case in any functional neuron.
In conclusion, the neuron of Hydra exhibits multidirectional conduction of nerve impulses within its nerve net, making the correct answer B: Multidirectional.
Test: Biology - 11 - Question 12
Ingression involves in the formation of
Detailed Solution for Test: Biology - 11 - Question 12
Ingression involves in the formation of Stereogastrula.
Explanation:
Ingression is a process that occurs during embryonic development in certain organisms, particularly in the animal kingdom. It involves the movement of cells from the surface layer of the embryo into the interior, resulting in the formation of new tissue layers. Ingression plays a crucial role in the formation of various structures and organs during development.
During ingression, cells undergo morphological changes and detach from the surface layer of the embryo. These cells then migrate towards the interior, where they contribute to the formation of different tissue layers. One of the outcomes of ingression is the formation of a structure called the gastrula.
The gastrula is a stage in embryonic development characterized by the presence of three distinct germ layers - ectoderm, mesoderm, and endoderm. These germ layers give rise to different tissues and organs in the developing organism. The formation of the gastrula is a result of the ingression process.
Among the options given, the formation of Stereogastrula involves ingression. Stereogastrula is a stage in embryonic development characterized by the presence of both ectoderm and endoderm layers, but lacking the mesoderm layer. This stage is found in certain organisms, such as sea urchins.
Therefore, the correct answer is B: Stereogastrula.
Test: Biology - 11 - Question 13
Pennatula is a
Detailed Solution for Test: Biology - 11 - Question 13
Pennatula is a
- Answer: C. Actinozoan
Detailed explanation:
- Pennatula is a type of marine organism commonly known as a sea pen.
- Sea pens belong to the phylum Cnidaria, which includes animals such as jellyfish, corals, and sea anemones.
- Within the phylum Cnidaria, sea pens specifically belong to the class Anthozoa.
- Anthozoa is further divided into two subclasses: Hexacorallia and Octocorallia.
- Pennatula belongs to the subclass Octocorallia, along with other organisms such as soft corals and gorgonians.
- Octocorallia are characterized by their eight-branched tentacles and a central axis made of a flexible protein called gorgonin.
- Pennatula and other sea pens are sessile organisms, meaning they are attached to the ocean floor and do not move around freely.
- They are filter feeders, using their tentacles to capture small organisms and particles from the water.
- Pennatula is commonly found in deep-sea environments, where they form colonies and play important ecological roles in the marine ecosystem.
Key points:
- Pennatula is a type of sea pen.
- Sea pens belong to the phylum Cnidaria.
- Pennatula belongs to the class Anthozoa.
- Anthozoa is further divided into subclasses Hexacorallia and Octocorallia.
- Pennatula belongs to the subclass Octocorallia.
- Octocorallia are characterized by eight-branched tentacles and a central axis made of gorgonin.
- Pennatula is a sessile filter feeder found in deep-sea environments.
Test: Biology - 11 - Question 14
Hypnotoxin, chemically is a mixure of
Detailed Solution for Test: Biology - 11 - Question 14
Protein and phenol and it's use in Portuguese war because hypnotoxin is affected central nervous system.
Test: Biology - 11 - Question 15
The member of platyhelmenthes is
Detailed Solution for Test: Biology - 11 - Question 15
The member of platyhelminthes is:
A: Loa loa
- Loa loa is not a member of platyhelminthes. It is a parasitic nematode that causes loiasis in humans.
B: Wuchereria
- Wuchereria is also not a member of platyhelminthes. It is a parasitic filarial worm that causes lymphatic filariasis in humans.
C: Taenia
- Taenia is a member of platyhelminthes. It is a genus of parasitic tapeworms that infect the intestines of vertebrates, including humans. There are several species of Taenia, such as Taenia solium (pork tapeworm) and Taenia saginata (beef tapeworm), which can cause diseases in humans.
D: all of these
- The correct answer is D: all of these. Taenia is a member of platyhelminthes, and both Loa loa and Wuchereria are not members of this phylum.
Test: Biology - 11 - Question 16
One of the following is not a larval stage of liverfluke
Detailed Solution for Test: Biology - 11 - Question 16
Explanation:
Liverfluke:
Liverfluke is a parasitic flatworm that infects the liver and bile ducts of various mammals, including humans. It has a complex life cycle with multiple larval stages.
Larval stages:
1. Redia: Redia is the larval stage of liverfluke that develops from the miracidium. It is a sac-like structure with a mouth and digestive system. Redia reproduce asexually to produce more rediae or develop into cercariae.
2. Cercaria: Cercaria is the next larval stage of liverfluke that develops from redia. It is a free-swimming larva with a tail and is released from the snail intermediate host into water. Cercariae can infect the final host directly or encyst as metacercariae on vegetation.
3. Miracidium: Miracidium is the first larval stage of liverfluke. It hatches from the eggs shed in the host's feces and infects a specific species of snail intermediate host. Inside the snail, miracidium develops into sporocysts, which further produce rediae.
4. Dipinnaria: Dipinnaria is not a larval stage of liverfluke. It is a larval stage of some species of starfish and sea urchins.
Therefore, the correct answer is C: dipinnaria.
Test: Biology - 11 - Question 17
Besides annelida and arthropoda, the metamerism is exihibited by
Detailed Solution for Test: Biology - 11 - Question 17
Explanation:
Metamerism refers to the division of the body into segments or repeated units. In addition to annelida (segmented worms) and arthropoda (arthropods), metamerism is also exhibited by cestoda (tapeworms).
Reasoning:
- Trematodes, also known as flukes, do not exhibit metamerism. They have a non-segmented body plan.
- Acanthocephala, commonly known as thorny-headed worms, also lack metamerism. They have a cylindrical body without distinct segments.
Conclusion:
Therefore, the correct answer is option B: cestoda.
Test: Biology - 11 - Question 18
The study of worms causing parasitic infestation in human is
Detailed Solution for Test: Biology - 11 - Question 18
The study of worms causing parasitic infestation in humans is helminthology.
Helminthology is the branch of biology that specifically deals with the study of worms, also known as helminths, that can cause parasitic infestations in humans. Here is a detailed explanation:
What are helminths?
- Helminths are a type of parasitic worms that can infect humans and cause various diseases and health problems.
- They include different types of worms such as roundworms, tapeworms, flukes, and hookworms.
What is helminthology?
- Helminthology is a specialized field of study within the broader discipline of parasitology that focuses specifically on the study of helminths.
- It involves the identification, classification, lifecycle, morphology, behavior, and pathology of helminths.
Why is helminthology important?
- Helminth infections are prevalent in many parts of the world, particularly in areas with poor sanitation and limited access to clean water.
- These infections can lead to significant health problems, including malnutrition, anemia, impaired cognitive development, organ damage, and even death.
- Understanding the biology and characteristics of helminths is crucial for developing effective prevention strategies, diagnostic methods, and treatment options.
Methods and techniques used in helminthology:
- Helminthology involves various laboratory techniques and methods to study helminths, including:
- Microscopic examination of helminth specimens to identify and classify different species.
- Molecular techniques such as DNA sequencing to determine genetic relationships among different helminth species.
- Experimental studies to investigate the lifecycle, behavior, and host-parasite interactions of helminths.
- Epidemiological studies to assess the prevalence, distribution, and risk factors associated with helminth infections.
In conclusion, helminthology is the field of study that focuses on the worms causing parasitic infestations in humans. It plays a vital role in understanding and combating helminth infections to improve human health.
Test: Biology - 11 - Question 19

A cross section at mid point of the middle piece of human sperm will show

Detailed Solution for Test: Biology - 11 - Question 19
Answer:
The cross section at the midpoint of the middle piece of a human sperm will show the following structures:
1. Centriole: This is a cylindrical structure found at the base of the middle piece of the sperm. It plays a crucial role in cell division and the formation of the sperm tail.
2. Mitochondria: These are the powerhouses of the cell and are responsible for producing energy in the form of ATP. In the middle piece of the sperm, mitochondria are present in abundance to provide the necessary energy for the sperm's motility.
3. Arrangement of microtubules: The middle piece of the sperm contains a 9+2 arrangement of microtubules. This refers to nine outer microtubule doublets surrounding a central pair of microtubules. This arrangement provides structural support and allows for the sliding of microtubules, which generates the whip-like movement of the sperm tail.
In summary, a cross section at the midpoint of the middle piece of a human sperm will show the presence of centriole, mitochondria, and a 9+2 arrangement of microtubules. Therefore, the correct answer is C: Mitochondria and 9 2 arrangement of microtubules.
Test: Biology - 11 - Question 20
Which is not formed by Wolffian duct ?
Detailed Solution for Test: Biology - 11 - Question 20
The correct answer is D: Oviduct.
Explanation:
The Wolffian duct is a structure that forms the male reproductive system during embryonic development. It gives rise to several structures including the epididymis, vas deferens, and ejaculatory duct. However, it does not contribute to the formation of the oviduct, which is part of the female reproductive system.
Details:
Here are some key points to consider:
- The Wolffian duct is present in both males and females during early development.
- In males, the Wolffian duct develops into the epididymis, vas deferens, and ejaculatory duct.
- The epididymis is a coiled tube located on the surface of the testis, where sperm mature and are stored.
- The vas deferens is a muscular tube that transports sperm from the epididymis to the urethra during ejaculation.
- The ejaculatory duct is formed by the union of the vas deferens and the duct from the seminal vesicle. It passes through the prostate gland and empties into the urethra.
- In females, the Wolffian duct regresses and does not contribute to the formation of the oviduct.
- The oviduct, also known as the fallopian tube, is a tube that connects the ovary to the uterus. It is responsible for the transport of eggs and is the site of fertilization.
In summary, the oviduct is not formed by the Wolffian duct, while the epididymis, vas deferens, and ejaculatory duct are all derived from the Wolffian duct.
Test: Biology - 11 - Question 21

Acrosome of sperm contains

Detailed Solution for Test: Biology - 11 - Question 21
Acrosome of sperm contains:
- Hyaluronidase: This enzyme helps in breaking down the hyaluronic acid present in the outer layer of the egg, allowing the sperm to penetrate and fertilize it.
- Acrosin: This protease enzyme is involved in the breakdown of proteins in the zona pellucida, which is the protective layer surrounding the egg.
- Other enzymes: The acrosome also contains other enzymes such as neuraminidase and proacrosin, which aid in the fertilization process.
Correct Answer: A: Hyaluronidase and acrosin.
Test: Biology - 11 - Question 22
Gametes are fromed in animals from
Detailed Solution for Test: Biology - 11 - Question 22
Explanation:
Gametes are specialized reproductive cells that are involved in sexual reproduction. They are responsible for transmitting genetic information from one generation to the next. In animals, gametes are formed through a process called gametogenesis, which occurs in the gonads (testes in males and ovaries in females).
Gamete Formation in Animals:
Gametes in animals are formed from epithelial tissue, specifically from cells known as germ cells. Germ cells are a type of stem cell that gives rise to gametes. Here is a detailed explanation of the process:
1. Germ Cell Migration: During early development, germ cells migrate from their place of origin to the developing gonads.
2. Meiosis: Once the germ cells reach the gonads, they undergo a specialized type of cell division called meiosis. Meiosis consists of two rounds of division, resulting in the formation of haploid gametes with half the number of chromosomes as the parent cell.
3. Spermatogenesis (in males): In males, the germ cells undergo spermatogenesis in the testes. This process involves several stages, including the production of spermatogonia (immature sperm) and their maturation into spermatozoa (mature sperm).
4. Oogenesis (in females): In females, the germ cells undergo oogenesis in the ovaries. This process also involves several stages, including the production of oogonia (immature eggs) and their maturation into ova (mature eggs).
5. Fertilization: Once the gametes are formed, they can be released from the gonads and are capable of fertilization. Fertilization occurs when a sperm cell combines with an egg cell, resulting in the formation of a zygote.
Therefore, the correct answer is D: Epithelial tissue. Gametes are formed from germ cells within the epithelial tissue of the gonads in animals.
Test: Biology - 11 - Question 23
Spermogenesis/spermateleosis is formation of spemtatiozoa from
Detailed Solution for Test: Biology - 11 - Question 23
Spermogenesis/spermateleosis is the formation of spermatzoa from:
Explanation:
Spermogenesis, also known as spermateleosis, is the process of spermatid maturation into spermatozoa. It occurs in the seminiferous tubules of the testes and involves several stages of development.
The correct answer is C: Spermatids. Spermatids are the immature male germ cells that undergo further changes to become mature spermatozoa.
Here is a detailed explanation of the different stages of spermogenesis:
1. Primary spermatocyte: This is the initial stage of spermogenesis. Primary spermatocytes are diploid cells that undergo meiosis I to produce two secondary spermatocytes.
2. Secondary spermatocyte: Secondary spermatocytes are haploid cells that result from meiosis I. They undergo meiosis II to produce four haploid spermatids.
3. Spermatids: Spermatids are haploid cells that are the immediate precursors to spermatozoa. They undergo a series of morphological changes, including the development of a head, tail, and flagellum, to become mature spermatozoa.
4. Geminal cells of testes: While geminal cells (also known as germ cells) are involved in the process of spermatogenesis, they are not directly responsible for the formation of spermatozoa. Geminal cells refer to the cells that give rise to spermatozoa, including spermatogonia, primary spermatocytes, and secondary spermatocytes.
In conclusion, spermogenesis/spermateleosis is the process of spermatid maturation into spermatozoa, with spermatids being the specific stage where this transformation occurs.
Test: Biology - 11 - Question 24

The head of mature mammalian sperm is made of

Detailed Solution for Test: Biology - 11 - Question 24
The head of mature mammalian sperm is made of:
- An acrosome: The acrosome is a cap-like structure located at the anterior end of the sperm head. It contains enzymes that are essential for the sperm to penetrate and fertilize the egg.
- Elongated nucleus covered by acrosome: The nucleus of the sperm is elongated and contains the genetic material. It is covered by the acrosome, which helps protect and prepare the genetic material for fertilization.
- Two centrioles and an axial filament: The sperm head contains two centrioles, which are involved in the formation of the microtubules that make up the sperm's tail. The axial filament, also known as the flagellum, is responsible for the sperm's motility and helps it move towards the egg.
- Nucleus, acrosome, cytoplasm, and mitochondrial sheath: The mature mammalian sperm head also contains the nucleus, which contains the genetic material, the acrosome, which helps with fertilization, the cytoplasm, which provides energy for the sperm's movement, and the mitochondrial sheath, which produces this energy.
Therefore, the correct answer is B: Elongated nucleus covered by acrosome.
Test: Biology - 11 - Question 25
Sugar fructose is present in the secretion of
Detailed Solution for Test: Biology - 11 - Question 25
Sugar fructose is present in the secretion of Seminal vesicles.
The seminal vesicles are a pair of glands located behind the bladder and connected to the ejaculatory ducts. They play a crucial role in the production of semen, which is a fluid that helps nourish and transport sperm.
Fructose is a type of sugar that provides energy for sperm cells. It is secreted by the seminal vesicles and forms a significant component of semen.
Here are some key points to remember:
- Seminal vesicles: These glands are responsible for producing a significant portion of semen and contribute to its overall composition.
- Fructose: The sugar fructose is present in the secretion of seminal vesicles.
- Energy for sperm: Fructose provides energy for sperm cells, allowing them to swim and fertilize an egg.
- Semen composition: In addition to fructose, semen also contains other substances such as proteins, enzymes, vitamins, and minerals that are essential for sperm function and survival.
In conclusion, sugar fructose is present in the secretion of seminal vesicles, which is an important component of semen.
Test: Biology - 11 - Question 26
Somatic chromosome number is 40. What shall chromosome number in the cells of seminiferous tubule ?
Detailed Solution for Test: Biology - 11 - Question 26
In testis, the immature male germ cells (spermatogonia) produce sperms by spermatogenesis, that begins at puberty. The spermatogonia (sing. spermatogonium) present on the inside wall of seminiferous tubules multiply by mitotic division and increase in numbers. Each spermatogonium is diploid and contains 46 chromosomes (in question this number is given as 40). Some of the spermatogonia called primary spermatocytes periodically undergo meiosis. A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of two equal, haploid cells called secondary spermatocytes, which have only 23 chromosomes each (in question this number is given as 20). The secondary spermatocytes undergo the second meiotic division to produce four equal, haploid spermatids (chromosome number 20). The spermatids are transformed into spermatozoa (sperms) by the process called spermiogenesis. After spermiogenesis, sperm heads become embedded in the sertoli cells, and are finally released from the seminiferous tubules by the process called spermiation.
Test: Biology - 11 - Question 27
Cryptochidism is a condition of testes
Detailed Solution for Test: Biology - 11 - Question 27
Cryptorchidism is a condition of testes:
Explanation:
Cryptorchidism refers to the condition in which one or both testes fail to descend into the scrotal sacs. This condition is quite common in newborns and infants, but it typically resolves on its own within the first few months of life. However, if the testes do not descend by the age of 6 months, medical intervention may be required.
The detailed solution is as follows:
1. Definition:
- Cryptorchidism is a condition in which the testes, which are normally located in the scrotal sacs, fail to descend properly.
2. Symptoms:
- The absence of testes in the scrotal sacs is the primary symptom of cryptorchidism.
- Other symptoms may include an empty scrotal sac, smaller size of the scrotum, or a palpable lump in the groin area.
3. Causes:
- Cryptorchidism can have various causes, including hormonal imbalances, genetic factors, and anatomical abnormalities.
- Premature birth is also known to increase the risk of cryptorchidism.
4. Diagnosis:
- Cryptorchidism is usually diagnosed through physical examination.
- An ultrasound may be performed to locate the undescended testes.
5. Complications:
- If left untreated, cryptorchidism can lead to several complications, including infertility, testicular cancer, and an increased risk of testicular torsion.
6. Treatment:
- Treatment for cryptorchidism depends on the age of the patient and the severity of the condition.
- Hormone therapy may be prescribed to stimulate testicular descent.
- Surgical intervention, called orchidopexy, may be necessary if the testes do not descend on their own.
7. Prognosis:
- With early intervention, the prognosis for individuals with cryptorchidism is generally good.
- Successful treatment can help prevent complications and restore normal testicular function.
Test: Biology - 11 - Question 28
Testosterone is produced by
Detailed Solution for Test: Biology - 11 - Question 28
Testosterone production
Testosterone is a hormone that plays a crucial role in the development and maintenance of male reproductive tissues. It is primarily produced in the testes in males and in smaller amounts in the ovaries and adrenal glands in females. Specifically, testosterone is produced by Leydig cells in the testes.
Leydig cells
Leydig cells, also known as interstitial cells, are located in the testes and are responsible for the production of testosterone. These cells are found in the connective tissue surrounding the seminiferous tubules, which are the structures where sperm production occurs. Leydig cells are stimulated by luteinizing hormone (LH) from the pituitary gland to produce testosterone.
Function of testosterone
Testosterone has various important functions in the body, including:
1. Development of male sex organs: Testosterone is responsible for the development of the male reproductive organs, such as the penis and testes, during fetal development.
2. Secondary sexual characteristics: Testosterone promotes the development of secondary sexual characteristics in males, such as facial and body hair, deepening of the voice, and increased muscle mass.
3. Sperm production: Testosterone is essential for the production of sperm in the testes.
4. Libido and sexual function: Testosterone plays a role in maintaining a healthy sex drive and sexual function in males.
5. Bone and muscle health: Testosterone helps maintain bone density and muscle strength.
6. Mood and cognition: Testosterone has an impact on mood, cognitive function, and overall well-being.
In conclusion, testosterone is primarily produced by Leydig cells in the testes. These cells are stimulated by luteinizing hormone to produce testosterone, which plays a crucial role in various aspects of male reproductive health and development.
Test: Biology - 11 - Question 29
Adaptation of eye in dark occurs due to
Detailed Solution for Test: Biology - 11 - Question 29
Adaptation of eye in dark occurs due to:
There are two types of photoreceptor cells in the retina of the eye - rods and cones. Rods are responsible for vision in dim light, while cones are responsible for color vision and visual acuity in bright light. The adaptation of the eye in the dark refers to the ability of the eye to adjust and function optimally in low-light conditions. This adaptation occurs due to the following reasons:
1. Repletion of visual pigment in rods:
- Rod cells contain a visual pigment called rhodopsin, which is responsible for detecting light in low-light conditions.
- In the dark, the concentration of rhodopsin increases in the rod cells, making them more sensitive to light.
- This repletion of visual pigment allows the rods to capture even small amounts of light and enhance our ability to see in the dark.
2. Depletion of visual pigment in cones:
- Cones contain a different visual pigment called photopsin, which is responsible for color vision and visual acuity in bright light.
- In the dark, the concentration of photopsin decreases in the cone cells, making them less sensitive to light.
- This depletion of visual pigment in cones reduces their ability to function effectively in low-light conditions, which is why we rely more on our rod cells for vision in the dark.
Therefore, the correct answer is D: Repletion of visual pigment in rods.
Test: Biology - 11 - Question 30
Scala tympani is connected to scala vestibuli by means of
Detailed Solution for Test: Biology - 11 - Question 30
The helicotrema is the part of the cochlear labyrinth where the scala tympani and the scala vestibuli meet. It is the main component of the cochlear apex. The hair cells near this area best detect low frequency sounds.
Test: Biology - 11 - Question 31

For seeing the nearby objects, the lens becomes more convex by

Detailed Solution for Test: Biology - 11 - Question 31
Explanation:
To see nearby objects clearly, the lens of the eye needs to become more convex. This process is known as accommodation. Accommodation is achieved through the contraction of the ciliary muscles, which are located in the ciliary body of the eye. The ciliary muscles are responsible for controlling the shape of the lens.
Here's a detailed explanation of each option:
A: Relaxation of iris muscles:
- The iris muscles are responsible for controlling the size of the pupil, not the shape of the lens.
- Relaxation of the iris muscles would cause the pupil to dilate, allowing more light to enter the eye, but it would not affect the shape of the lens.
B: Contraction of iris muscles:
- As mentioned earlier, the iris muscles control the size of the pupil, not the shape of the lens.
- Contraction of the iris muscles would cause the pupil to constrict, reducing the amount of light entering the eye, but it would not affect the shape of the lens.
C: Contraction of ciliary muscles:
- The ciliary muscles are responsible for controlling the shape of the lens.
- When the ciliary muscles contract, they relax the tension on the suspensory ligaments attached to the lens, allowing the lens to become more convex and focus on nearby objects.
D: Relaxation of ciliary muscles:
- Relaxation of the ciliary muscles would cause the tension on the suspensory ligaments to increase, making the lens less convex.
- This would result in the lens focusing on distant objects rather than nearby objects.
Therefore, the correct answer is option C: Contraction of ciliary muscles.
Test: Biology - 11 - Question 32
In mammals, the organs of Corti is found in
Detailed Solution for Test: Biology - 11 - Question 32
Organs of Corti in Mammals
The organs of Corti are specialized structures found in the cochlea of the mammalian inner ear. These organs play a crucial role in hearing and are responsible for converting sound vibrations into electrical signals that can be interpreted by the brain.
Location of the Organs of Corti
The organs of Corti are specifically located within the cochlear duct, also known as the scala media. The scala media is one of the three chambers or canals that make up the cochlea, which is responsible for transmitting sound signals from the outer ear to the brain.
Structure of the Organs of Corti
The organs of Corti consist of sensory hair cells and supporting cells that are arranged in a highly organized manner. These hair cells are responsible for detecting sound vibrations and converting them into electrical signals.
Function of the Organs of Corti
The organs of Corti play a crucial role in the process of hearing. When sound waves enter the ear, they cause vibrations in the fluid-filled cochlea. These vibrations are then detected by the sensory hair cells of the organs of Corti. The hair cells convert these mechanical vibrations into electrical signals, which are then transmitted to the brain through the auditory nerve.
Conclusion
In summary, the organs of Corti, which are responsible for converting sound vibrations into electrical signals, are found in the scala media, one of the chambers of the cochlea in mammals.
Test: Biology - 11 - Question 33
Opacity of eye lens leads to
Detailed Solution for Test: Biology - 11 - Question 33
Opacity of eye lens leads to Cataract.
Explanation:
Cataract is a condition where the lens of the eye becomes cloudy or opaque, leading to a decrease in vision. This opacity of the lens can be caused by various factors such as age, genetics, trauma, or certain medical conditions.
Here is a detailed explanation of why opacity of the eye lens leads to cataract:
1. Anatomy of the eye: The lens is a clear, flexible structure located behind the iris (colored part of the eye). It helps focus light onto the retina, which sends visual signals to the brain.
2. Normal lens function: In a healthy eye, the lens is transparent and allows light to pass through it without obstruction. This enables clear vision at different distances.
3. Opacity of the lens: When the lens becomes cloudy or opaque, it interferes with the passage of light through the eye. This causes blurry or hazy vision, similar to looking through a foggy window.
4. Cause of cataract: The opacity of the lens occurs due to changes in the protein structure within the lens fibers. These changes can be a result of aging, injury, exposure to ultraviolet radiation, or certain medical conditions like diabetes.
5. Types of cataract: There are different types of cataracts, including age-related cataracts, congenital cataracts (present at birth), traumatic cataracts (caused by injury), and secondary cataracts (resulting from other eye conditions or medication use).
6. Effects on vision: As the cataract progresses, it can lead to a gradual decline in vision. Common symptoms include blurred vision, difficulty seeing in dim light, sensitivity to glare, and the perception of halos around lights.
7. Treatment: The only effective treatment for cataract is surgical removal of the opaque lens and replacement with an artificial intraocular lens. Cataract surgery is a common and safe procedure that can restore clear vision.
In conclusion, the opacity of the eye lens leads to cataract, a condition characterized by a cloudy or opaque lens that impairs vision. Prompt diagnosis and surgical intervention can help restore clear vision and improve the quality of life for individuals with cataracts.
Test: Biology - 11 - Question 34
Cornea transplatation is successful as cornea
Detailed Solution for Test: Biology - 11 - Question 34
Cornea Transplantation: Successful Factors
B: Without blood supply
- One of the main reasons why cornea transplantation is successful is because the cornea does not have any blood supply.
- The cornea receives its nutrients and oxygen from the tears and aqueous humor in the front part of the eye.
- This lack of blood supply reduces the risk of rejection and improves the chances of a successful transplant.
Easily Available
- Corneas are readily available for transplantation.
- There is a constant supply of corneas from deceased individuals who have donated their organs.
- The availability of corneas ensures that patients in need can receive timely transplants.
Easily Preserved
- The cornea can be easily preserved for transplantation.
- It can be stored in a special solution at low temperatures, which helps to maintain its viability and integrity.
- This allows for corneas to be transported over long distances and stored until they are needed for transplantation.
Easily Stitched
- The cornea is a highly adaptable tissue that can be easily stitched.
- Surgeons can suture the transplanted cornea onto the recipient's eye using fine sutures.
- The cornea has a unique structure that allows for precise and secure stitching, ensuring a successful transplantation.
In conclusion, cornea transplantation is successful due to several factors, including the cornea's lack of blood supply, its easy availability, ability to be preserved, and the ease of stitching it onto the recipient's eye. These factors contribute to the high success rates of cornea transplants and the restoration of vision for many patients in need.
Test: Biology - 11 - Question 35

Four healthy people in their twenties got involved in injuries resulting in damage and death of a few cells.Which of the following cells are least likely to be replaced by new cells

Detailed Solution for Test: Biology - 11 - Question 35

Introduction:
Injuries can result in damage and death of cells in the body. However, the body has mechanisms to replace damaged cells with new ones. This process of cell replacement is known as cell regeneration.
Explanation:
Among the given options, neurons are least likely to be replaced by new cells. Here's why:
1. Liver cells:
- Liver cells have a high regenerative capacity.
- The liver can regenerate and replace damaged cells, allowing it to recover from injuries.
2. Malpighian layer of skin:
- The Malpighian layer of skin is the innermost layer of the epidermis.
- Skin cells have a relatively high turnover rate and can be replaced through cell division.
- The skin has the ability to heal and regenerate itself, replacing damaged cells.
3. Osteocytes:
- Osteocytes are cells found in bone tissue.
- While bone regeneration is a slower process compared to other tissues, osteocytes can be replaced over time.
- The body has mechanisms to repair and remodel bone tissue, allowing for the replacement of damaged osteocytes.
4. Neurons:
- Neurons are specialized cells that transmit electrical signals in the nervous system.
- Unlike other cells, neurons have a limited ability to regenerate.
- In the central nervous system, including the brain and spinal cord, neuron regeneration is minimal or absent.
- In the peripheral nervous system, some neurons can regenerate to a certain extent, but the process is slow and often incomplete.
Conclusion:
In summary, among the given options, neurons are the least likely to be replaced by new cells. While the liver, skin, and bone have regenerative capacities to varying degrees, the regeneration of neurons is limited, especially in the central nervous system.
Test: Biology - 11 - Question 36
If after cutting through dorsal root of a spinal nerve of a mammals, the associated receptor in skin was simulated the animal would
Detailed Solution for Test: Biology - 11 - Question 36
Explanation:
When the dorsal root of a spinal nerve is cut, it disrupts the communication between the sensory receptor in the skin and the spinal cord. As a result, the animal would show no response to the stimulation. Here's a detailed explanation:
1. Dorsal Root of Spinal Nerve:
- The dorsal root of a spinal nerve contains sensory fibers that transmit signals from the sensory receptors in the skin to the spinal cord.
2. Cutting the Dorsal Root:
- When the dorsal root is cut, it severs the connection between the sensory receptor and the spinal cord.
3. Disruption of Signal Transmission:
- After cutting the dorsal root, the signals from the receptor in the skin cannot reach the spinal cord.
4. Lack of Sensory Input:
- Without the transmission of signals, the animal would not be able to perceive or feel the stimulation on the skin.
5. No Response:
- As a result, the animal would show no response to the simulated stimulation.
Therefore, the correct answer is B: Show no response.
Test: Biology - 11 - Question 37
Preganglionic sympathetic fibres are
Detailed Solution for Test: Biology - 11 - Question 37
Explanation:
- Preganglionic sympathetic fibers refer to the nerve fibers that originate in the intermediolateral cell column of the spinal cord and synapse with postganglionic sympathetic neurons in the autonomic ganglia.
- These fibers release a neurotransmitter called acetylcholine, which makes them cholinergic.
- The release of acetylcholine from preganglionic fibers activates nicotinic receptors on the postganglionic neurons.
- This activation leads to the release of another neurotransmitter, norepinephrine, from the postganglionic sympathetic fibers, which are adrenergic.
- Adrenergic fibers release norepinephrine at their target organs, where it binds to adrenergic receptors to initiate the physiological response.
- Therefore, the correct answer is B: Cholinergic.
Test: Biology - 11 - Question 38
Parasymphatic nervous system in not involved in
Detailed Solution for Test: Biology - 11 - Question 38
Parasympathetic Nervous System and Its Functions
The parasympathetic nervous system is a division of the autonomic nervous system that generally functions to conserve and restore energy. It is often referred to as the "rest and digest" system because it promotes activities that occur when the body is at rest or in a relaxed state. Here is a detailed explanation of why the parasympathetic nervous system is not involved in the dilation of the pupil:
Peristalsis:
- Peristalsis refers to the coordinated contractions of smooth muscles in the digestive system that propel food through the gastrointestinal tract.
- The parasympathetic nervous system is responsible for stimulating peristalsis and promoting digestion.
- Therefore, it is involved in peristalsis.
Secretion of Saliva:
- The parasympathetic nervous system plays a vital role in stimulating the secretion of saliva.
- It activates salivary glands, leading to an increased production of saliva.
- Hence, it is involved in the secretion of saliva.
Dilation of Pupil:
- The dilation of the pupil is controlled by the sympathetic nervous system, not the parasympathetic nervous system.
- The sympathetic nervous system is responsible for the fight or flight response, which includes the dilation of the pupil to enhance vision in response to potential threats or arousal.
- The parasympathetic nervous system, on the other hand, constricts the pupil in normal resting conditions.
- Therefore, the parasympathetic nervous system is not involved in the dilation of the pupil.
Excitation of Reproductive Organs:
- The parasympathetic nervous system is responsible for promoting sexual arousal and initiating the physiological responses involved in sexual activity.
- It stimulates the release of nitric oxide, leading to the dilation of blood vessels and increased blood flow to the reproductive organs.
- Thus, it is involved in the excitation of reproductive organs.
In conclusion, the parasympathetic nervous system is not involved in the dilation of the pupil (option C) but is involved in peristalsis, secretion of saliva, and excitation of reproductive organs.
Test: Biology - 11 - Question 39

Eye muscles are innervated by

Detailed Solution for Test: Biology - 11 - Question 39
The innervation of eye muscles is as follows:
Oculomotor nerve (cranial nerve III):
- Innervates the superior rectus muscle, which elevates the eye.
- Innervates the inferior rectus muscle, which depresses the eye.
- Innervates the medial rectus muscle, which adducts the eye.
- Innervates the inferior oblique muscle, which elevates and abducts the eye.
Trochlear nerve (cranial nerve IV):
- Innervates the superior oblique muscle, which depresses and abducts the eye.
Abducens nerve (cranial nerve VI):
- Innervates the lateral rectus muscle, which abducts the eye.
The correct answer is B:
- Oculomotor, trochlear, and abducens nerves are responsible for innervating the eye muscles.
Note:
- The vagus nerve (cranial nerve X) and facial nerve (cranial nerve VII) do not directly innervate the eye muscles.
Test: Biology - 11 - Question 40
The branched tree-like structure/ Tree of life present in the cerebellum is
Detailed Solution for Test: Biology - 11 - Question 40
The branched tree-like structure/ Tree of life present in the cerebellum is the Arbor vitae.
The cerebellum is a region of the brain that plays a crucial role in motor coordination, balance, and posture. It is located at the back of the brain, beneath the occipital lobes of the cerebral cortex.
Arbor vitae, which means "tree of life" in Latin, refers to the branched tree-like structure present in the cerebellum.
Here is a detailed explanation of the Arbor vitae in the cerebellum:
- Anatomical Structure: The cerebellum consists of two hemispheres connected by a central vermis. Within each hemisphere, there are three main deep cerebellar nuclei: the fastigial nucleus, the interposed nucleus (composed of the globose and emboliform nuclei), and the dentate nucleus. These nuclei are surrounded by the cerebellar cortex, which is highly folded and contains numerous folia (ridges) and sulci (grooves).
- White Matter: The Arbor vitae is composed of white matter tracts that resemble the branches of a tree. These tracts consist of myelinated axons that carry information between different regions of the cerebellum and connect it with other parts of the brain.
- Purpose: The Arbor vitae acts as a communication network within the cerebellum, allowing for the integration and coordination of motor signals. It receives input from various sources, including the cerebral cortex, spinal cord, and sensory organs, and sends output to the deep cerebellar nuclei. This intricate connectivity enables the cerebellum to fine-tune and modulate motor movements, ensuring their accuracy and precision.
- Function: The cerebellum, with the help of the Arbor vitae, plays a crucial role in motor control and coordination. It assists in maintaining balance, regulating muscle tone, and refining voluntary movements. Damage to the Arbor vitae or the cerebellum as a whole can lead to motor deficits, such as ataxia (uncoordinated movements), tremors, and difficulties with balance and posture.
In conclusion, the Arbor vitae is the branched tree-like structure present in the cerebellum. It serves as a communication network within the cerebellum, allowing for the integration and coordination of motor signals necessary for smooth and precise movements.
Test: Biology - 11 - Question 41

Route of reflex are is

Detailed Solution for Test: Biology - 11 - Question 41
Route of Reflex Arc:
The correct answer is option C: Receptors, sensory fibers, grey matter, motor fibers, and effectors.
Here is a detailed explanation of each component in the reflex arc and their sequence:
1. Receptors:
- Receptors are specialized sensory structures that detect changes in the environment or stimuli.
- They can be located in various parts of the body, such as the skin, muscles, tendons, and organs.
- Receptors convert the stimuli into electrical signals known as nerve impulses.
2. Sensory Fibers:
- Sensory fibers are nerve fibers that carry the nerve impulses from the receptors to the central nervous system (CNS).
- These fibers are a part of the peripheral nervous system (PNS).
- They transmit the sensory information towards the CNS for processing.
3. Grey Matter:
- Grey matter refers to the regions of the CNS where the cell bodies of neurons are concentrated.
- In the spinal cord, the grey matter is present in the inner region, while in the brain, it is found in specific areas.
- In the reflex arc, the sensory information reaches the grey matter for processing and integration.
4. Motor Fibers:
- Motor fibers are nerve fibers that carry the nerve impulses from the CNS to the effectors.
- Similar to sensory fibers, motor fibers are also a part of the PNS.
- These fibers transmit motor commands from the CNS to the effectors, resulting in a response.
5. Effectors:
- Effectors are the muscles or glands that respond to the motor commands initiated by the CNS.
- Muscles contract or relax, while glands secrete substances as a response to the stimuli.
- The effectors generate the final action or response to the initial stimulus.
Sequence of the Reflex Arc:
- The reflex arc follows a specific sequence from the initial stimulus to the final response.
- It can be summarized as: Receptors -> Sensory Fibers -> Grey Matter -> Motor Fibers -> Effectors.
- This sequential pathway allows for a quick and involuntary response to a stimulus without involving conscious thought.
Therefore, option C is the correct answer as it accurately represents the route of the reflex arc, starting from the receptors, passing through sensory fibers, grey matter, motor fibers, and ending at the effectors.
Test: Biology - 11 - Question 42

Given below are assertion and reason . Point out if both are true with reason being correct explanation(A), both true but reason is not correct explanation(B), assertion is true but reason is wrong (C), and both are wrong (D).
Assertion : In humans the gamette contributed by the male determines whether the child produced will be male or female
Reasson : Sex in hymans is polygenic trait dependent upon the cumulative effect of some genes on Xchromosome and some on Y-chromosome

Detailed Solution for Test: Biology - 11 - Question 42
Explanation:
The correct answer is option C, which states that the assertion is true but the reason is wrong.
Assertion: In humans, the gamete contributed by the male determines whether the child produced will be male or female.
Reason: Sex in humans is a polygenic trait dependent upon the cumulative effect of some genes on the X chromosome and some on the Y chromosome.
Let's break down the explanation further:
- The assertion is true that the gamete contributed by the male determines the sex of the child because males can contribute either an X or a Y chromosome in their sperm. If the sperm carries an X chromosome, the resulting child will be female, and if it carries a Y chromosome, the child will be male.
- However, the reason given is incorrect. Sex in humans is determined by the presence or absence of the Y chromosome. If the fertilizing sperm carries a Y chromosome, the resulting child will be male, regardless of the genes on the X or Y chromosome. The presence of the Y chromosome triggers the development of male characteristics.
- The polygenic trait mentioned in the reason refers to traits that are influenced by multiple genes. While there are many genes on both the X and Y chromosomes that influence various aspects of sexual development and secondary sexual characteristics, the determining factor for sex is the presence or absence of the Y chromosome.
Therefore, the assertion is true, but the reason is not a correct explanation. Hence, option C is the correct answer.
Test: Biology - 11 - Question 43

Given below are assertion and reason . Point out if both are true with reason being correct explanation(A), both true but reason is not correct explanation(B), assertion is true but reason is wrong (C), and both are wrong (D).
Assertion : Owls move freely during night
Reason : They have large number of rods on their retina

Detailed Solution for Test: Biology - 11 - Question 43
Assertion: Owls move freely during the night.
Reason: They have a large number of rods on their retina.

The correct answer is (A) both the assertion and reason are true, with the reason being the correct explanation. Here's why:
1. Assertion: Owls move freely during the night.
- Owls are nocturnal birds, which means they are adapted to be active during the night. They have specialized features that allow them to move effectively in low-light conditions.
- Owls possess excellent night vision, which helps them navigate and hunt in the dark. They can spot their prey, such as small rodents, even in dimly lit environments.
2. Reason: They have a large number of rods on their retina.
- Rods are photoreceptor cells in the retina that are responsible for vision in low-light conditions, such as during the night.
- Owls have a higher density of rods in their retinas compared to humans and many other animals. This allows them to gather more light and enhances their night vision capabilities.
Therefore, the reason given in the statement correctly explains why owls can move freely during the night. The large number of rods on their retina improves their ability to see in low-light conditions, enabling them to navigate and hunt effectively.
Test: Biology - 11 - Question 44

Given below are assertion and reason . Point out if both are true with reason being correct explanation(A), both true but reason is not correct explanation(B), assertion is true but reason is wrong (C), and both are wrong (D).
Assertion : Merozoites are the resultant stage of Erythrocytic cycle
Reasson : Schizogony occurs in Erythrocytes & Hepatocytes

Detailed Solution for Test: Biology - 11 - Question 44
Assertion: Merozoites are the resultant stage of Erythrocytic cycle.
Reason: Schizogony occurs in Erythrocytes & Hepatocytes.
The correct answer is A. Both the assertion and reason are true, and the reason is the correct explanation for the assertion. Here's why:
- Merozoites are indeed the resultant stage of the Erythrocytic cycle. In the life cycle of malaria parasites, the Erythrocytic cycle is the phase where the parasites multiply within the red blood cells (erythrocytes). During this cycle, the parasites undergo several stages of development, including the formation of merozoites.
- Schizogony refers to the asexual reproduction of the malaria parasite within the host's cells. It occurs in both erythrocytes (red blood cells) and hepatocytes (liver cells). During schizogony, the parasite undergoes multiple rounds of nuclear division (schizont stage) followed by the formation of multiple daughter cells (merozoites) within the host cell. Therefore, the reason stating that schizogony occurs in erythrocytes and hepatocytes is correct.
In conclusion, the merozoites are indeed the resultant stage of the Erythrocytic cycle, and the reason for this is the occurrence of schizogony in erythrocytes and hepatocytes.
Test: Biology - 11 - Question 45

Given below are assertion and reason . Point out if both are true with reason being correct explanation(A), both true but reason is not correct explanation(B), assertion is true but reason is wrong (C), and both are wrong (D).
Assertion : Promastigole stage is the enfective stage of Leishmania donovani
Reason : It cause Espundia disease

Detailed Solution for Test: Biology - 11 - Question 45
Assertion: Promastigole stage is the infective stage of Leishmania donovani.
Reason: It causes Espundia disease.
The correct answer is C (Assertion is true but reason is wrong).
Explanation:
- The promastigote stage is indeed the infective stage of Leishmania donovani, which is a protozoan parasite that causes the disease called visceral leishmaniasis or kala-azar.
- However, the reason given that it causes Espundia disease is incorrect. Espundia, also known as mucocutaneous leishmaniasis, is caused by a different species of Leishmania, specifically Leishmania braziliensis.
- Leishmania donovani is responsible for visceral leishmaniasis, which primarily affects the internal organs such as the spleen, liver, and bone marrow.
- Therefore, while the assertion is true, the reason provided is incorrect and does not explain the relationship between the promastigote stage and Espundia disease.
Test: Biology - 11 - Question 46
Hepatitis-B surface antigens are product of
Detailed Solution for Test: Biology - 11 - Question 46
Introduction: Hepatitis-B surface antigens are proteins present on the surface of the hepatitis B virus (HBV). They play a crucial role in the diagnosis and prevention of hepatitis B infection.
Answer: The correct answer is C: Saccharomyces cerevisiae.
Explanation:
Hepatitis-B surface antigens are produced using recombinant DNA technology, where specific genes are inserted into host organisms to produce the desired protein. In the case of hepatitis B surface antigens, the gene encoding the antigen is inserted into the DNA of a host organism.
Saccharomyces cerevisiae, commonly known as baker's yeast, is a commonly used host organism for the production of hepatitis B surface antigens. Here's why:
1. Safety: Saccharomyces cerevisiae is a non-pathogenic yeast commonly used in food and beverage production. It has a long history of safe use in various applications, making it a suitable choice for the production of antigens.
2. Protein production: Saccharomyces cerevisiae has the ability to produce large amounts of proteins. It provides a suitable environment for the expression and secretion of the hepatitis B surface antigens.
3. Post-translational modifications: Saccharomyces cerevisiae is capable of performing post-translational modifications on the proteins it produces. This is important for the correct folding and functional properties of the hepatitis B surface antigens.
4. Cost-effectiveness: Saccharomyces cerevisiae is relatively easy and cost-effective to cultivate and maintain in the laboratory. This makes it a practical choice for large-scale production of hepatitis B surface antigens.
In summary, Saccharomyces cerevisiae is a commonly used host organism for the production of hepatitis B surface antigens due to its safety, protein production capabilities, post-translational modification abilities, and cost-effectiveness.
Test: Biology - 11 - Question 47
“Crylac” gene commonly occurs in a type of
Detailed Solution for Test: Biology - 11 - Question 47
Bacteria from all four groups perform important services related to water dynamics, nutrient cycling, and disease suppression. Some bacteria affect water movement by producing substances that help bind soil particles into small aggregates (those with diameters of 1/10,000-1/100 of an inch or 2-200m). Stable aggregates improve water infiltration and the soil’s water-holding ability. In a diverse bacterial community, many organisms will compete with disease-causing organisms in roots and on aboveground surfaces of plants.
Test: Biology - 11 - Question 48
“Postal Transmission of spores of Bacteria possible during wars” which one Bacteria type applicable about above said statement among the following
Detailed Solution for Test: Biology - 11 - Question 48
The process of forming an endospore is complex. The model organism used to study endospore formation is Bacillus subtilis. Endospore development requires several hours to complete. Key morphological changes in the process have been used as markers to define stages of development.
Test: Biology - 11 - Question 49
BCG for Tuberculosis and Measles given as
Detailed Solution for Test: Biology - 11 - Question 49
BCG for Tuberculosis and Measles given as:
A: Intradermally
- BCG (Bacillus Calmette-Guérin) vaccine is administered intradermally, which means it is injected just below the surface of the skin.
- The BCG vaccine is primarily used for protection against tuberculosis (TB), although it has also been found to provide some protection against leprosy.
- Intradermal administration involves the injection of a small amount of the BCG vaccine into the top layers of the skin.
- This method allows the vaccine to stimulate an immune response and trigger the development of immunity against TB.
B: Extradermally
- There is no known method of extradermal administration for the BCG vaccine.
- Extradermal administration refers to the injection of a substance outside of the skin, which is not a recognized method for administering the BCG vaccine.
C: Both 1 and 2
- The correct answer is not C because there is no recognized extradermal administration for the BCG vaccine.
D: Intravenous
- The correct answer is not D because the BCG vaccine is not administered intravenously (directly into a vein).
- Intravenous administration is not suitable for the BCG vaccine as it requires a different method of delivery.
Therefore, the correct answer is A: Intradermally.
Test: Biology - 11 - Question 50
Test for Typhoid is
Detailed Solution for Test: Biology - 11 - Question 50
Test for Typhoid is:
There are several tests available for diagnosing typhoid fever. Among them, the most commonly used test is the Widal test. The Widal test is a serological test that detects antibodies against Salmonella typhi, the bacteria that causes typhoid fever. Here is a detailed explanation of the test:
Widal Test:
- The Widal test is an agglutination test that detects antibodies in the patient's blood that are specific to the S. typhi bacteria.
- It involves mixing the patient's serum (the liquid portion of blood) with a suspension of killed S. typhi bacteria in a test tube.
- If the patient has been infected with S. typhi, their serum will contain specific antibodies that will cause agglutination (clumping) of the bacteria in the test tube.
- Agglutination is observed by the formation of visible clumps or a change in the appearance of the mixture.
- The test measures the presence and levels of antibodies to the S. typhi antigens O and H. A positive result indicates a recent or current infection with S. typhi.
Other tests for typhoid fever include:
Lepromin Test:
- The lepromin test is used to diagnose leprosy, not typhoid fever. It is a delayed-type hypersensitivity test that detects the immune response to Mycobacterium leprae, the bacteria that causes leprosy.
TLC and DLC:
- Total leukocyte count (TLC) and differential leukocyte count (DLC) are routine blood tests that assess the number and types of white blood cells in the blood.
- These tests are not specific for typhoid fever and do not directly detect the presence of S. typhi bacteria.
ELISA:
- Enzyme-linked immunosorbent assay (ELISA) is a laboratory technique used to detect and measure antibodies or antigens in a patient's blood sample.
- ELISA can be used to detect specific antibodies against S. typhi in the blood, but it is not as commonly used as the Widal test for diagnosing typhoid fever.
In conclusion, the correct test for typhoid fever is the Widal test, which detects specific antibodies against S. typhi bacteria. Other tests like the lepromin test, TLC, DLC, and ELISA are not specific for typhoid fever or are not commonly used for its diagnosis.
Test: Biology - 11 - Question 51
Kotch,s pastulate failed over
Detailed Solution for Test: Biology - 11 - Question 51
Kotch's Pastulate Failure:
The pastulate failure mentioned in the question refers to the failure of Kotch's postulate, which is a set of criteria used to determine whether a specific microorganism causes a particular disease. In this case, Kotch's pastulate failed to identify the causative agent of the disease.
Possible Causes of the Disease:
There are multiple options provided in the question as possible causes of the disease. Let's examine each one:
A: Viral Disease:
- Viral diseases are caused by viruses, which are microorganisms that require a host cell to replicate.
- Examples of viral diseases include influenza, measles, and HIV/AIDS.
- Kotch's postulate may have failed because the disease in question is caused by a virus, and the criteria used in the postulate are not applicable to viral infections.
B: Leprosy Disease:
- Leprosy, also known as Hansen's disease, is a chronic infectious disease caused by the bacterium Mycobacterium leprae.
- Kotch's postulate may have failed if the disease in question is indeed leprosy, as the postulate may not be suitable for identifying this specific bacterium.
C: Hansen Disease:
- Hansen's disease is another name for leprosy, as mentioned above.
- This option is essentially the same as option B, and the explanations provided there apply here as well.
D: All of These:
- This option suggests that all of the above options could be potential causes of the disease.
- Kotch's postulate may have failed because the disease is caused by multiple factors, such as a combination of viral and bacterial infections.
Conclusion:
Based on the information provided, it is difficult to determine the exact cause of the disease without further context or specific details. However, it can be concluded that Kotch's postulate failed to identify the causative agent, and the disease could potentially be caused by any of the options mentioned (viral disease, leprosy, or a combination of both).
Test: Biology - 11 - Question 52
Trichoderma used in the
Detailed Solution for Test: Biology - 11 - Question 52
Trichoderma is a genus of fungi that has been widely used in various agricultural practices. It is known for its beneficial effects on plant growth and protection against diseases. Trichoderma can be used in the biological control of diseases, as a biofertilizer in paddy fields, and also plays a role in the formation of basidiomycetes fruiting bodies.
Here is a detailed explanation of Trichoderma's uses:
A. Biological control of disease:
- Trichoderma has been extensively studied and utilized as a biocontrol agent against various plant pathogens.
- It has the ability to produce enzymes that can degrade the cell walls of pathogens, leading to their death.
- Trichoderma also competes with pathogens for nutrients and space, further suppressing their growth.
- It can be applied as a biocontrol agent to protect crops from diseases, reducing the need for chemical pesticides.
B. Paddy field as biofertilizer:
- Trichoderma has the ability to solubilize nutrients in the soil, making them more available to plants.
- It can enhance nutrient uptake by plants, leading to improved growth and yield.
- When applied to paddy fields, Trichoderma can improve soil fertility and nutrient cycling, resulting in increased productivity.
C. Basidiomycetes fruiting body formation:
- Trichoderma has been found to have an association with basidiomycetes, a group of fungi that produce fruiting bodies.
- It has been observed that Trichoderma can induce the formation of basidiomycetes fruiting bodies.
- This interaction between Trichoderma and basidiomycetes can play a role in the ecology and diversity of fungal communities.
D. All of these:
- Trichoderma's uses in biological control, biofertilizer, and basidiomycetes fruiting body formation are not mutually exclusive.
- It can be employed in all of these applications, depending on the specific needs and goals of agricultural practices.
In conclusion, Trichoderma is a versatile fungus that can be used in the biological control of diseases, as a biofertilizer in paddy fields, and has an association with basidiomycetes fruiting body formation. Its diverse applications make it a valuable tool in agriculture for promoting plant growth and protecting crops from diseases.
Test: Biology - 11 - Question 53

Bordaeux mixture consist of

Detailed Solution for Test: Biology - 11 - Question 53
Bordaeux mixture consists of:
- A: Copper sulfate (CuSO4)
- B: Calcium hydroxide (Ca(OH)2)
- C: Water
Detailed
The Bordaeux mixture is a fungicide and bactericide solution that is commonly used in agriculture to control various plant diseases. It is a mixture of copper sulfate (CuSO4), calcium hydroxide (Ca(OH)2), and water. Each component plays a specific role in the effectiveness of the mixture:
- Copper sulfate (CuSO4): Copper sulfate is a highly effective fungicide and bactericide. It acts by inhibiting the growth and reproduction of fungi and bacteria. It is particularly effective against diseases such as downy mildew, black spot, and bacterial blight.
- Calcium hydroxide (Ca(OH)2): Calcium hydroxide, also known as slaked lime, is added to the mixture to neutralize the acidity of copper sulfate. This helps to prevent phytotoxicity or damage to the plants.
- Water: Water is added to the mixture to dilute the copper sulfate and calcium hydroxide. It acts as a carrier for the active ingredients and allows for better coverage and penetration of the plant surfaces.
Conclusion:
In conclusion, the Bordaeux mixture consists of copper sulfate, calcium hydroxide, and water. These components work together to effectively control plant diseases and promote healthy plant growth.
Test: Biology - 11 - Question 54
Parasexuality discovered in a
Detailed Solution for Test: Biology - 11 - Question 54
The Parasexual Cycle is defined as a cycle in which plasmogamy, karyogamy and meiosis (haploidisation) take place but not at a specified time or at specified points in the life-cycle of an organism.Generally parasexual cycle occurs in those fungi in which true sexual cycle does not take place. The members of class Deuteromycetes (Deuteromycotina) in which sexual cycle does not occur, exhibit parasexual cycle generally.Parasexual cycle was first discovered by Pontecarvo and Roper of University of Glasgow in 1952 in Aspergillus nidulans, the imperfect stage of Emericella nidulans. Since then parasexual cycle has been discovered not only in several members of Deuteromycetes but also in fungi belonging to Ascomycetes and Basidiomycetes.
CORRECT OPTION IS (A).
Test: Biology - 11 - Question 55
Heterothallism prevent
Detailed Solution for Test: Biology - 11 - Question 55
According to Blakeslee (1904) Heterothallic condition is “essentially similar to that in dioecious plants and animals and although in this case the two complimentary individuals which are needed for sexual reproduction are in general not so conspicuously differentiated morphologically as in higher forms, such a morphological difference is often distinctly visible.”So the answer would be interbreeding.
Test: Biology - 11 - Question 56
Related to
Test: Biology - 11 - Question 57
Predator fungi belong to class of
Detailed Solution for Test: Biology - 11 - Question 57
Predator fungi belong to class of
There are several classes of fungi, but predator fungi specifically belong to the class Fungi imperfectii, also known as Deuteromycetes. Here's a detailed explanation:
1. Fungi imperfectii:
- Predator fungi are a type of fungi that do not have a known sexual reproductive stage or have not been observed to reproduce sexually.
- They are often referred to as imperfect fungi because they lack the sexual reproductive structures found in other classes of fungi.
- Fungi imperfectii include a diverse range of fungi, including those that prey on other organisms such as nematodes, insects, and other fungi.
2. Other classes of fungi:
- Gill fungi (class Basidiomycetes) are characterized by the presence of gills on the underside of their fruiting bodies, which produce and release spores.
- Sac fungi (class Ascomycetes) are characterized by the production of spores within sac-like structures called asci.
- Algal fungi (class Oomycetes) are not true fungi but are often referred to as fungi due to their similar appearance and ecological roles. They include water molds and downy mildews.
3. Characteristics of predator fungi:
- Predator fungi have evolved mechanisms to capture and consume other organisms.
- They often produce specialized structures such as adhesive traps or constricting rings to capture their prey.
- Some predator fungi are also capable of actively penetrating and infecting their prey organisms, releasing enzymes to break them down and absorb the nutrients.
4. Importance of predator fungi:
- Predator fungi play a crucial role in regulating populations of other organisms in ecosystems.
- They help control populations of pests and disease-causing organisms, making them valuable in agricultural and ecological contexts.
- Predator fungi also contribute to nutrient recycling by decomposing organic matter and releasing nutrients back into the environment.
Therefore, predator fungi belong to the class Fungi imperfectii, which is characterized by their lack of a known sexual reproductive stage.
Test: Biology - 11 - Question 58

Lichens are the major pollution indicators of

Detailed Solution for Test: Biology - 11 - Question 58
Lichens as Pollution Indicators:
Lichens are unique organisms that consist of a symbiotic relationship between a fungus and an alga or a cyanobacterium. Due to their sensitivity to environmental changes, lichens are widely used as bioindicators to assess pollution levels. In particular, lichens can indicate the presence of certain pollutants, including:
1. SO2 (Sulfur Dioxide):
Lichens are highly sensitive to sulfur dioxide, a common air pollutant released from burning fossil fuels. They can accumulate sulfur dioxide in their tissues, leading to visible changes and damage in their morphology and physiology.
2. NO2 (Nitrogen Dioxide):
Lichens can also provide information about nitrogen dioxide pollution. They are particularly sensitive to this gas, which is released from combustion processes, vehicle emissions, and industrial activities. High levels of nitrogen dioxide can lead to lichen bleaching and decline.
3. Mercury:
While lichens cannot directly indicate the presence of mercury, they can indirectly reflect its levels in the environment. Mercury can be absorbed by lichens through atmospheric deposition, and their health and vitality can be affected by the presence of this heavy metal.
4. CO (Carbon Monoxide):
Lichens are not commonly used to indicate carbon monoxide pollution. Unlike sulfur dioxide and nitrogen dioxide, carbon monoxide does not directly affect lichens' growth and vitality.
In conclusion, lichens are most commonly used as pollution indicators for sulfur dioxide (SO2) and nitrogen dioxide (NO2). They can provide valuable insights into the levels of these pollutants in the environment and help assess air quality and pollution impacts.
Test: Biology - 11 - Question 59
Rock flower is
Detailed Solution for Test: Biology - 11 - Question 59
Rock flower is
There are several different types of rock flowers, but in this case, the correct answer is B: Parmelia.
Explanation:
Parmelia is a genus of lichenized fungi in the family Parmeliaceae. Lichens are a symbiotic relationship between a fungus and an alga or cyanobacterium. They are often found growing on rocks, trees, or soil surfaces.
Here are some key points to support the answer:
- Parmelia is a common type of rock flower found in many different habitats, including forests, deserts, and tundras.
- It is characterized by its leaf-like structure and can range in color from gray to green to yellow.
- Parmelia lichens are often used in traditional medicine for their antimicrobial and anti-inflammatory properties.
- They can also be used as indicators of air pollution, as they are sensitive to changes in the environment.
- Other types of rock flowers, such as Peltigera, Usnea, and Leucanora, may also be found in different regions but are not specifically referred to as rock flowers in the question.
Therefore, the correct answer is B: Parmelia.
Test: Biology - 11 - Question 60
Small molecular weight compound synthesized in plant tissue and accumulate in response to microbial challange or other type of strees known as
Detailed Solution for Test: Biology - 11 - Question 60
Phytoalexins are small molecular weight compounds synthesized in plant tissue in response to microbial challenge or other types of stress. These compounds play an important role in the plant's defense mechanism against pathogens. Here is a detailed explanation of phytoalexins:
Definition:
- Phytoalexins are low molecular weight compounds that are synthesized by plants in response to microbial infection or other forms of stress.
- They are typically produced in the site of infection or injury in order to protect the plant from further damage.
Role of Phytoalexins:
- Phytoalexins act as antimicrobial agents, inhibiting the growth and spread of pathogens.
- They also help to limit the damage caused by microbial infection by promoting the production of other defense compounds.
- Phytoalexins can also have signaling functions, alerting neighboring cells and tissues of the presence of pathogens and triggering additional defense responses.
Synthesis of Phytoalexins:
- Phytoalexins are synthesized through a complex series of biochemical reactions within plant cells.
- The synthesis is usually induced by the activation of specific genes in response to microbial challenge or stress signals.
- The precursors for phytoalexin synthesis are often stored in plant cells and are rapidly converted into active compounds upon stimulation.
Accumulation of Phytoalexins:
- Phytoalexins accumulate at the site of infection or injury, forming a localized defense barrier.
- The accumulation of phytoalexins is often accompanied by visible changes in the plant tissue, such as browning or necrosis.
- The level of accumulation may vary depending on the severity of the stress and the plant species.
Examples of Phytoalexins:
- There are many different types of phytoalexins, and their chemical structures can vary greatly.
- Some common examples include resveratrol in grapes, pisatin in pea plants, and capsidiol in peppers.
- These compounds have been found to have antimicrobial properties and play a role in plant defense against pathogens.
In conclusion, phytoalexins are small molecular weight compounds synthesized in plant tissue in response to microbial challenge or other types of stress. They act as antimicrobial agents, limit the damage caused by pathogens, and can have signaling functions. The synthesis and accumulation of phytoalexins are highly regulated processes that contribute to the plant's defense mechanism.
Test: Biology - 11 - Question 61
When microorganism cannot grow an a minimal media unless additional nutrient are supplied to the growth medium known as
Detailed Solution for Test: Biology - 11 - Question 61
Explanation:
When microorganisms cannot grow in a minimal media unless additional nutrients are supplied, they are known as auxotrophs. Here is a detailed explanation:
Auxotrophs:
1. Auxotrophs are microorganisms that have lost the ability to synthesize certain essential nutrients required for growth.
2. They are unable to grow on minimal media, which is a basic growth medium that contains only the essential nutrients required for growth.
3. These microorganisms require additional nutrients to be supplied in the growth medium in order to support their growth.
4. The additional nutrients can be specific amino acids, vitamins, or other essential compounds that the auxotrophs cannot produce on their own.
5. Without the supplementation of these nutrients, the auxotrophs cannot synthesize the necessary components for growth and therefore cannot grow in minimal media.
Other Options:
1. Prototrophs: These are microorganisms that can grow on minimal media without the need for additional nutrients. They have the ability to synthesize all the essential nutrients required for growth.
2. Wild type: This refers to the normal or natural phenotype of a microorganism, which may or may not be able to grow on minimal media without additional nutrients.
3. Biotrophs: These are microorganisms that obtain nutrients from living host organisms.
Therefore, the correct answer is B: Auxotrophs.
Test: Biology - 11 - Question 62
Which one is immunogenic in bacteria
Detailed Solution for Test: Biology - 11 - Question 62
Glycocalyx is immunogenic in bacteria
Explanation:
The immunogenicity of different components in bacteria can vary. In this case, the immunogenic component is glycocalyx. Here is a detailed explanation:
Glycocalyx:
- Glycocalyx is a gelatinous layer that surrounds the cell wall of bacteria.
- It is composed of polysaccharides, polypeptides, or both.
- Glycocalyx can be either capsule or slime layer.
- Capsule is a well-organized layer firmly attached to the cell wall, while slime layer is loosely attached.
- It serves various functions, including protection against phagocytosis, desiccation, and immune response.
- The polysaccharide composition of glycocalyx can induce an immune response in the host.
Other options:
While glycocalyx is the correct answer in this case, let's also briefly explain the other options:
Cell wall:
- Cell wall is present in most bacteria and provides structural support.
- While it can trigger an immune response, it is not specifically known for its immunogenicity.
Teichoic acid:
- Teichoic acids are specific to certain types of bacteria, such as Gram-positive bacteria.
- They are involved in cell wall maintenance and regulation of cell division.
- Teichoic acids can stimulate the immune system and induce an immune response.
Porin protein:
- Porin proteins are present in the outer membrane of Gram-negative bacteria.
- They form channels that allow the passage of molecules.
- While they can interact with the immune system, their immunogenicity is not as well-documented as glycocalyx.
Therefore, in summary, glycocalyx is the immunogenic component in bacteria.
Test: Biology - 11 - Question 63

‘Ciprofloxacin’ inhibit the bacterial growth by

Detailed Solution for Test: Biology - 11 - Question 63
Explanation:
Ciprofloxacin is an antibiotic that belongs to the fluoroquinolone class. It inhibits the growth of bacteria by targeting their DNA replication process. Here is a detailed explanation of how ciprofloxacin works:
Inhibition of DNA replication:
- Ciprofloxacin specifically targets bacterial DNA gyrase and topoisomerase IV enzymes, which are essential for DNA replication.
- These enzymes play a crucial role in unwinding and separating the DNA strands during replication.
- Ciprofloxacin binds to these enzymes and prevents them from carrying out their normal function, thereby inhibiting DNA replication.
Effect on bacterial growth:
- By inhibiting DNA replication, ciprofloxacin disrupts the bacteria's ability to replicate and multiply.
- This leads to a halt in bacterial growth and eventually results in the death of the bacteria.
- Ciprofloxacin is effective against a wide range of bacteria, including both Gram-positive and Gram-negative bacteria.
Additional Mechanisms:
- Ciprofloxacin may also have additional mechanisms of action that contribute to its antibacterial activity.
- It has been suggested that ciprofloxacin can interfere with bacterial protein synthesis by targeting the ribosomes.
- This could potentially lead to the inhibition of translation, which is the process by which proteins are synthesized in bacteria.
- However, the primary mechanism of ciprofloxacin's antibacterial activity is the inhibition of DNA replication.
In conclusion, ciprofloxacin inhibits bacterial growth primarily by targeting the enzymes involved in DNA replication. This disruption of DNA replication leads to the cessation of bacterial multiplication and eventually causes the death of the bacteria.
Test: Biology - 11 - Question 64

Rocky mountain spotted fever caused by Rickttsias which transmission towards Human being can not possible with out

Detailed Solution for Test: Biology - 11 - Question 64
Explanation:
Rocky Mountain spotted fever is a bacterial infection caused by the bacterium Rickettsia rickettsii. The transmission of this disease to humans is primarily through arthropod vectors. Here is a detailed explanation of each option and why C is the correct answer:
A. Air: Rocky Mountain spotted fever cannot be transmitted through the air. It is not an airborne disease and does not spread through respiratory droplets.
B. Contaminated food and water: This disease is not transmitted through contaminated food and water. It is not a waterborne or foodborne illness.
C. Arthropods vectors: The primary mode of transmission for Rocky Mountain spotted fever is through arthropod vectors, particularly ticks. Ticks infected with Rickettsia rickettsii can transmit the bacteria to humans when they bite and feed on their blood.
D. Blood: While it is true that the bacteria Rickettsia rickettsii can be found in the blood of infected individuals, direct transmission of Rocky Mountain spotted fever through blood is rare. The main mode of transmission is through the bite of infected ticks.
In conclusion, the correct answer is C. Arthropods vectors, specifically ticks, are the main mode of transmission for Rocky Mountain spotted fever. It is important to take preventive measures when in tick-infested areas to reduce the risk of infection.
Test: Biology - 11 - Question 65

Low conjugation and high recomobination found in the crossing of a bacteria with

Detailed Solution for Test: Biology - 11 - Question 65
Explanation:
To determine which combination of bacteria would result in low conjugation and high recombination, we need to understand the characteristics of each strain and how they interact during the process of genetic transfer.
Conjugation is the transfer of genetic material from one bacterial cell to another through direct cell-to-cell contact. Recombination, on the other hand, is the process by which genetic material from two different sources is combined to form new combinations of genes.
Let's analyze each option and its implications for conjugation and recombination:
A: F+ x F- strain
- In this case, the F+ strain has a fertility factor (F factor) which allows it to donate genetic material during conjugation.
- The F- strain lacks the F factor and can only receive genetic material.
- Conjugation is likely to occur, resulting in the transfer of genetic material from the F+ strain to the F- strain.
- However, recombination is less likely to occur since the F- strain can only receive genetic material and not exchange it with the F+ strain.
- This combination does not fit the criteria of low conjugation and high recombination.
B: F- x F- strain
- In this case, both strains lack the F factor and cannot donate genetic material during conjugation.
- Conjugation is unlikely to occur since neither strain can act as a donor.
- Recombination is also unlikely since there is no exchange of genetic material between the two strains.
- This combination does not fit the criteria of low conjugation and high recombination.
C: Hfr x F- strain
- In this case, the Hfr (high frequency of recombination) strain has the F factor integrated into its genome.
- The F- strain lacks the F factor and can only receive genetic material.
- Conjugation is likely to occur, with the Hfr strain acting as the donor and transferring its entire genome to the F- strain.
- Since the Hfr strain has the F factor integrated into its genome, the transferred genetic material can include genes from different regions of the bacterial chromosome.
- This increases the likelihood of recombination, as the transferred genes can recombine with the recipient strain's genome.
- This combination fits the criteria of low conjugation and high recombination.
D: F+ x F+ strain
- In this case, both strains have the F factor and can act as donors during conjugation.
- Conjugation is likely to occur, with both strains exchanging genetic material.
- Recombination can occur since both strains can donate and receive genetic material, allowing for the exchange and combination of genes.
- However, the presence of the F factor in both strains may limit the diversity of the transferred genetic material, resulting in lower recombination compared to the Hfr x F- strain.
- This combination does not fit the criteria of low conjugation and high recombination.
Therefore, the correct answer is C: Hfr x F- strain, which would result in low conjugation and high recombination.
Test: Biology - 11 - Question 66
Nitrogen fixation carried out by
Detailed Solution for Test: Biology - 11 - Question 66
Nitrogen fixation carried out by:
There are several microorganisms that are involved in nitrogen fixation, which is the process of converting atmospheric nitrogen (N2) into a form that plants can use.
Option A: Azotobacter and Frankia
- Azotobacter: A genus of bacteria that can fix nitrogen aerobically. They are free-living organisms found in soil and water.
- Frankia: A genus of bacteria that can fix nitrogen symbiotically with certain plants, such as alders and some woody plants.
Option B: BGA (Blue-Green Algae) and Rhizobium
- BGA: Also known as cyanobacteria, they are photosynthetic bacteria that can fix nitrogen. They are commonly found in aquatic environments.
- Rhizobium: A genus of bacteria that forms a symbiotic relationship with leguminous plants, such as peas and beans, to fix nitrogen.
Option C: Nitrosomonas and Nitrobacteria
- Nitrosomonas: A genus of bacteria that carries out the first step of nitrification, converting ammonia (NH3) into nitrite (NO2-).
- Nitrobacteria: A genus of bacteria that carries out the second step of nitrification, converting nitrite (NO2-) into nitrate (NO3-).
Option D: All of these
- Nitrogen fixation is carried out by all of the microorganisms mentioned above. Each group of microorganisms plays a specific role in the nitrogen cycle, either by fixing nitrogen directly or by facilitating the conversion of nitrogen compounds.
In conclusion, nitrogen fixation is carried out by Azotobacter, Frankia, BGA, Rhizobium, Nitrosomonas, and Nitrobacteria. These microorganisms play a crucial role in the nitrogen cycle, ensuring the availability of nitrogen for plant growth and ecosystem functioning.
Test: Biology - 11 - Question 67
Pure culture of single microrganism growing in a medium free from other living organism known as
Detailed Solution for Test: Biology - 11 - Question 67
Pure culture of single microorganism growing in a medium free from other living organisms known as:
Answer: B. Axenic culture
Explanation:
An axenic culture refers to a pure culture of a single microorganism that is grown in a medium completely free from other living organisms. This type of culture is essential for conducting various experiments and studies in microbiology and other related fields. Here are some key points to understand about axenic culture:
1. Definition: Axenic culture is a term used to describe a culture in which only one type of microorganism is present, with no contamination or interference from other organisms.
2. Importance: Axenic cultures are crucial for studying the characteristics, growth requirements, and behavior of specific microorganisms. They allow researchers to isolate and identify individual strains, study their growth patterns, and conduct various experiments under controlled conditions.
3. Techniques for obtaining axenic cultures: There are several techniques utilized to obtain axenic cultures, including:
- Sterilization: Ensuring that the growth medium, equipment, and containers used for culturing are free from any contaminants.
- Serial dilution: Diluting the original sample to such an extent that only a single microorganism remains in each subculture.
- Isolation techniques: Employing techniques such as streak plate method or pour plate method to isolate single colonies of the desired microorganism.
4. Application areas: Axenic cultures find applications in diverse fields such as medicine, agriculture, biotechnology, and environmental sciences. They are used in research, vaccine production, pharmaceutical development, and the study of microorganism-host interactions.
In conclusion, axenic culture is the term used to describe a pure culture of a single microorganism grown in a medium free from other living organisms. It is an essential tool in microbiology research and allows for the detailed study of individual microorganisms and their characteristics.
Test: Biology - 11 - Question 68
After Clamp-connection resulting mycelium with
Detailed Solution for Test: Biology - 11 - Question 68
Clamp-connection resulting mycelium with A: n n condition
The clamp-connection is a specialized structure formed during cell division in certain fungi. It helps maintain the genetic stability of the mycelium by ensuring that each daughter cell receives a complete set of chromosomes. When a clamp-connection is formed, there are several possible conditions that can arise:
1. n n condition:
- In this condition, the clamp-connection is formed between two haploid cells.
- Each cell contains a single set of chromosomes (n).
- The clamp-connection ensures that each daughter cell receives a complete set of chromosomes during cell division, maintaining the haploid condition.
2. 2n condition:
- In this condition, the clamp-connection is formed between two diploid cells.
- Each cell contains two sets of chromosomes (2n).
- The clamp-connection helps in the proper distribution of chromosomes during cell division, maintaining the diploid condition.
3. n condition:
- In this condition, the clamp-connection is formed between a haploid and a diploid cell.
- The haploid cell contributes one set of chromosomes (n), while the diploid cell contributes two sets of chromosomes (2n).
- The clamp-connection ensures the proper distribution of chromosomes, maintaining a balanced genetic composition.
4. Coenocytic condition:
- In this condition, the clamp-connection is not formed, resulting in a multinucleate mycelium.
- The mycelium contains multiple nuclei within a shared cytoplasmic network.
- Without the clamp-connection, the distribution of chromosomes during cell division may be irregular, leading to a coenocytic condition.
Answer:
Based on the given options, the clamp-connection resulting mycelium is described by condition A: n n condition. This means that the clamp-connection is formed between two haploid cells, each containing a single set of chromosomes. The clamp-connection ensures the proper distribution of chromosomes during cell division, maintaining the haploid condition.
Test: Biology - 11 - Question 69

Study of structure, function, uses, effects and Biological importance of microorganism including protozoons, Algae, fungi,bacteria etc. known as

Detailed Solution for Test: Biology - 11 - Question 69
Study of structure, function, uses, effects, and Biological importance of microorganisms including protozoa, Algae, fungi, bacteria, etc. is known as Microbiology.
Microbiology is a branch of science that focuses on the study of microorganisms, including bacteria, fungi, protozoa, algae, and viruses. It involves the examination of their structure, function, uses, effects, and biological importance. Here is a detailed explanation of each component:
1. Structure: Microbiology involves the study of the physical characteristics and structures of microorganisms, including their size, shape, and cellular components. This includes understanding the different cell structures and organelles present in bacteria, fungi, protozoa, algae, and viruses.
2. Function: Microbiology explores the physiological processes and functions of microorganisms. This includes understanding their metabolic pathways, reproduction, growth, and adaptations to different environments. It also involves studying the interactions between microorganisms and their hosts or the environment.
3. Uses: Microorganisms have various uses in different fields. Microbiology helps in understanding and utilizing these uses. Some examples include the production of antibiotics, vaccines, enzymes, and other biotechnological products. Microorganisms are also used in agriculture, food industry, waste management, and environmental monitoring.
4. Effects: Microorganisms can have both positive and negative effects on living organisms and the environment. Microbiology investigates the harmful effects of pathogenic microorganisms that cause diseases in humans, animals, and plants. It also examines the beneficial effects of microorganisms, such as their role in nutrient cycling, decomposition, and symbiotic relationships.
5. Biological Importance: Microorganisms play a crucial role in various biological processes and ecosystems. Microbiology helps in understanding their importance in maintaining ecological balance, biogeochemical cycling, and the functioning of ecosystems. Microorganisms also contribute to the health and well-being of humans, animals, and plants through their involvement in digestion, immunity, and nutrient availability.
In conclusion, Microbiology is the study of microorganisms and their structure, function, uses, effects, and biological importance. It encompasses various aspects of microorganisms, including bacteria, fungi, protozoa, algae, and viruses, and their interactions with living organisms and the environment.
Test: Biology - 11 - Question 70

Replica plate experiment on E.coli bacteria was performed by

Detailed Solution for Test: Biology - 11 - Question 70
Replica Plate Experiment on E.coli Bacteria:
The replica plate experiment on E.coli bacteria was performed by Joshua Lederberg and Esther Lederberg. This experiment was a crucial step in understanding bacterial genetics and the phenomenon of genetic recombination. Here is a detailed explanation of the experiment:
Experimental Setup:
1. Two petri dishes were prepared, each containing agar medium.
2. The first petri dish was inoculated with a wild-type E.coli strain and allowed to grow.
3. After the bacteria formed colonies, a sterile velvet cloth was pressed onto the plate, transferring some of the bacterial cells onto the cloth.
Replica Plating:
1. The velvet cloth with the bacterial cells was then pressed onto the second petri dish, creating an exact replica of the bacterial colonies.
2. The second plate was supplemented with specific nutrients or antibiotics, creating different selective conditions.
Observations and Results:
1. The replica plate experiment allowed for the identification of mutants that were unable to grow under certain selective conditions.
2. These mutants were then analyzed further to understand the genetic changes that led to their inability to grow in specific environments.
3. By comparing the colonies on the two plates, the researchers could identify which mutants arose due to genetic recombination events.
Significance of the Experiment:
1. The replica plate experiment provided evidence for the occurrence of genetic recombination in bacteria.
2. It demonstrated that bacteria could acquire new genetic traits through horizontal gene transfer.
3. This experiment laid the foundation for further research in bacterial genetics and had significant implications in fields such as medicine and biotechnology.
Therefore, the replica plate experiment on E.coli bacteria was performed by Joshua Lederberg and Esther Lederberg.
Test: Biology - 11 - Question 71
Largest Bacteria is
Detailed Solution for Test: Biology - 11 - Question 71
Largest Bacteria is Epulopscium.
Explanation:
Definition:
- Bacteria are single-celled microorganisms that can be found in various environments.
- They come in different shapes and sizes, with some bacteria being larger than others.
Types of Bacteria:
1. Spirochetes:
- Spirochetes are a type of bacteria with a spiral shape.
- While they can be quite long, they are not considered the largest bacteria.
2. Epulopscium:
- Epulopscium is a large bacteria that can be found in the intestines of certain herbivorous animals, such as cows and sheep.
- These bacteria can reach lengths of up to 0.5 mm, making them one of the largest known bacteria.
3. Oscillatoria:
- Oscillatoria is a filamentous bacteria that forms long chains of cells.
- While they can be relatively large in terms of length, they are not considered the largest bacteria.
4. Acetabularia:
- Acetabularia is a single-celled green alga that can grow up to several centimeters in size.
- While it is a large microorganism, it is not classified as a bacteria.
Conclusion:
- Among the given options, Epulopscium is the largest bacteria, with lengths of up to 0.5 mm.
Test: Biology - 11 - Question 72
“Adenovirus” are polyhedral virus which can cause
Detailed Solution for Test: Biology - 11 - Question 72
Adenovirus: Causes and Characteristics
Adenovirus is a type of polyhedral virus that can cause various infections in humans. It is important to note that adenovirus does not cause AIDS, mad cow disease, or SARS. However, it is known to cause respiratory infections. Here's a detailed explanation:
1. Adenovirus:
- Adenoviruses are a group of viruses that infect the respiratory tract, eyes, gastrointestinal tract, and other parts of the body.
- They are non-enveloped viruses and have a polyhedral shape, meaning they have multiple sides or facets.
- There are different serotypes of adenovirus, each with its own characteristics and ability to cause disease.
2. Respiratory Infection:
- One of the most common illnesses caused by adenovirus is respiratory infection.
- Adenovirus respiratory infections can present as the common cold, bronchitis, or pneumonia.
- Symptoms may include fever, sore throat, cough, nasal congestion, and malaise.
- These infections are more common in children, but can also affect adults.
3. Other Infections:
- In addition to respiratory infections, adenovirus can also cause other types of infections.
- Adenoviral conjunctivitis is an infection of the eye that can cause redness, irritation, and discharge.
- Gastroenteritis caused by adenovirus can result in diarrhea, vomiting, abdominal pain, and fever.
- Adenovirus can also lead to urinary tract infections, meningitis, and other less common infections.
4. Transmission:
- Adenovirus is highly contagious and can spread through respiratory droplets, close personal contact, or contact with contaminated surfaces.
- Outbreaks of adenovirus infections can occur in crowded places, such as schools, military barracks, or daycare centers.
- Good hygiene practices, such as handwashing and covering the mouth and nose when coughing or sneezing, can help prevent the spread of adenovirus.
In conclusion, adenovirus is a polyhedral virus that can cause respiratory infections, among other types of infections. It is important to be aware of the symptoms and transmission of adenovirus to take appropriate preventive measures and seek medical attention when needed.
Test: Biology - 11 - Question 73

“LAB” can help in

Detailed Solution for Test: Biology - 11 - Question 73
Explanation:
The term "LAB" stands for Lactic Acid Bacteria, which is a type of bacteria commonly used in the food industry for various purposes. Here, we will discuss how LAB can help in the process of making Roquefort cheese.
Roquefort cheese making:
- LAB plays a crucial role in the production of Roquefort cheese, a famous blue cheese from France.
- Roquefort cheese is made from sheep's milk and it undergoes a unique fermentation process.
- The LAB present in the milk helps in the acidification process, which is necessary for cheese production.
- The LAB convert lactose (a sugar present in milk) into lactic acid, which lowers the pH of the milk and creates an acidic environment.
- This acidic environment is essential for the growth of Penicillium roqueforti, a mold that gives Roquefort cheese its distinct flavor and blue veins.
- LAB also contribute to the development of flavor and aroma compounds during the ripening of the cheese.
Therefore, LAB is an important component in the production of Roquefort cheese, helping in the acidification process and contributing to the development of flavor.
Test: Biology - 11 - Question 74

Which of the following organisms show single circulation?

Detailed Solution for Test: Biology - 11 - Question 74

In fishes, the heart pumps out deoxygenated blood which is oxygenated by the gills and is supplied to the body parts where deoxygenated blood is returned to the heart. This type of circulation is known as single circulation.

Test: Biology - 11 - Question 75

Brewers yeast is

Detailed Solution for Test: Biology - 11 - Question 75

The correct answer is A: Saccharomyces cerevisiae.
Saccharomyces cerevisiae, commonly known as brewer's yeast, is a type of yeast that is used in the brewing and baking industries. Here is a detailed explanation:
Definition:
- Brewer's yeast is a type of fungus belonging to the species Saccharomyces cerevisiae.
- It is a single-celled organism that is used in various industrial processes, including brewing and baking.
Key Points:
- Saccharomyces cerevisiae is the most commonly used species of yeast for brewing beer and making bread.
- It is a versatile yeast strain that can ferment sugars and produce alcohol and carbon dioxide.
- Brewer's yeast is known for its ability to convert sugar into alcohol during the fermentation process.
- It is responsible for the production of ethanol and carbon dioxide in beer and bread making.
- Brewer's yeast is rich in vitamins, minerals, and proteins, making it a popular nutritional supplement for humans and animals.
- It is often used as a dietary supplement to support digestion, boost the immune system, and promote overall health.
Conclusion:
Brewer's yeast is scientifically known as Saccharomyces cerevisiae. It is a versatile yeast strain used in brewing and baking industries and is also used as a nutritional supplement.
Test: Biology - 11 - Question 76
Full potential of “Penicillin” as an effective antibiotics was establish by
Detailed Solution for Test: Biology - 11 - Question 76
Full potential of “Penicillin” as an effective antibiotic was established by Ernest Chain.
Explanation:
Ernest Chain, along with Alexander Fleming and Howard Florey, played a significant role in the development and understanding of penicillin as an effective antibiotic. Here is a detailed explanation:
1. Discovery of Penicillin:
- Alexander Fleming discovered penicillin in 1928 while working at St. Mary's Hospital in London.
- He observed that a mold called Penicillium notatum had antibacterial properties that could inhibit the growth of certain bacteria.
2. Isolation and Initial Research:
- Fleming published his findings, but it was not until the 1940s that further research on penicillin was conducted.
- Howard Florey and his team at the University of Oxford, including Ernst Chain, focused on isolating and purifying penicillin to make it suitable for medical use.
3. Chain's Contributions:
- Ernest Chain, a biochemist, worked closely with Florey to develop methods for extracting and purifying penicillin.
- Chain's expertise in enzymology and chemistry played a crucial role in understanding the structure and properties of penicillin.
4. Mass Production:
- Chain and his colleagues successfully scaled up the production of penicillin using deep fermentation techniques.
- They collaborated with pharmaceutical companies to mass-produce penicillin during World War II, which greatly contributed to the treatment of bacterial infections.
5. Recognition and Nobel Prize:
- For their significant contributions to the development and mass production of penicillin, Fleming, Florey, and Chain jointly received the Nobel Prize in Physiology or Medicine in 1945.
6. Impact and Legacy:
- The discovery and development of penicillin revolutionized the field of medicine by introducing the era of antibiotics.
- Penicillin and subsequent antibiotics have saved countless lives and transformed the treatment of bacterial infections worldwide.
In conclusion, while Alexander Fleming discovered penicillin, it was the collaborative efforts of Fleming, Chain, and Florey that unlocked its full potential as an effective antibiotic. Ernest Chain's contributions to the isolation, purification, and production of penicillin were instrumental in establishing it as a game-changer in the field of medicine.
Test: Biology - 11 - Question 77

“Cycloporin-A” bioactive agent that is commonly used as immunosuppressive drug is the product by the fungus that is

Detailed Solution for Test: Biology - 11 - Question 77

The bioactive agent "Cycloporin-A" is commonly used as an immunosuppressive drug. It is produced by a specific fungus. Let's analyze the given options and find out which fungus produces Cycloporin-A:
A: Monascus purpureus:
- Monascus purpureus is a red mold fungus.
- It is known for its production of various bioactive compounds, including monacolins and pigments.
- However, there is no evidence to suggest that Monascus purpureus produces Cycloporin-A.
B: Trichoderma polysponum:
- Trichoderma polysponum is a species of fungi commonly found in soil and decaying wood.
- It has been reported to produce Cycloporin-A, which is a cyclic peptide with immunosuppressive properties.
- Therefore, Trichoderma polysponum is the correct answer.
C: Aspergillus niger:
- Aspergillus niger is a common fungus found in soil and decaying organic matter.
- It is known for producing various enzymes and organic acids but not Cycloporin-A.
D: Propioni bacterium sharmanii:
- Propionibacterium sharmanii is a bacterium, not a fungus.
- It is commonly used in the production of propionic acid and vitamin B12, but it does not produce Cycloporin-A.
Therefore, the correct answer is option B: Trichoderma polysponum.
Test: Biology - 11 - Question 78
Indirect gene transfer in plant biotechnology commonly carried out by
Detailed Solution for Test: Biology - 11 - Question 78
Indirect gene transfer in plant biotechnology commonly carried out by:
There are several methods used for indirect gene transfer in plant biotechnology, but the most common method is through natural genetic engineering of plants.
1. Natural genetic engineering of plants:
- This method involves using the natural mechanisms of gene transfer within plants.
- Plants have the ability to transfer genetic material between themselves through processes such as horizontal gene transfer and hybridization.
- By manipulating these natural processes, scientists can introduce desired genes into plants and achieve the desired traits.
2. Biological Scissors:
- Biological scissors, also known as molecular scissors or site-specific nucleases, are enzymes that can be used to cut DNA at specific locations.
- These scissors enable scientists to precisely target and edit genes in plants.
- By cutting the DNA at specific sites, scientists can introduce or remove specific genes to alter the characteristics of the plant.
3. Unicellular fungi:
- Unicellular fungi, such as Agrobacterium tumefaciens, can be used as a vector to transfer genes into plants.
- These fungi have the ability to infect plants and transfer their own genetic material into the plant's genome.
- By genetically modifying the fungi to carry desired genes, scientists can use them as a tool to transfer genes into plants.
4. Drosophila of plant kingdom:
- The term "Drosophila of the plant kingdom" refers to a small flowering plant called Arabidopsis thaliana.
- Arabidopsis thaliana is often used as a model organism in plant genetics research.
- Scientists can genetically modify Arabidopsis thaliana to study gene function and understand the genetic mechanisms in plants.
Conclusion:
- Indirect gene transfer in plant biotechnology is commonly carried out through natural genetic engineering of plants.
- This method takes advantage of the natural mechanisms of gene transfer within plants to introduce desired genes and achieve desired traits.
- Other methods, such as the use of biological scissors, unicellular fungi, and model organisms like Arabidopsis thaliana, can also be employed in specific cases.
Test: Biology - 11 - Question 79

B. thurigenesis effective against

Detailed Solution for Test: Biology - 11 - Question 79
B. thurigenesis effective against
The B. thurigenesis is a type of bacteria that is commonly used as a biological pesticide to control specific pests. In this case, we are looking for the pests that B. thurigenesis is effective against.
Here are the options and their corresponding pests:
A. Boll worm (Helicoperpa species)
- B. thurigenesis is effective against boll worms, which are pests that infest crops such as cotton and corn.
B. Ring worm (Tricophyton)
- B. thurigenesis is not effective against ring worms. Ring worms are actually a type of fungal infection that affects the skin, hair, and nails of humans and animals.
C. Silk worm (Bombax mori)
- B. thurigenesis is not effective against silk worms. Silk worms are actually the larval stage of the silk moth and are used in the production of silk.
D. Cotton (Gossypium species)
- B. thurigenesis is effective against pests that infest cotton crops, such as boll worms.
Answer: A. Boll worm (Helicoperpa species)
In summary, B. thurigenesis is effective against boll worms, which are pests that infest crops like cotton and corn. It is not effective against ring worms or silk worms.
Test: Biology - 11 - Question 80
ELISA based on the principle of
Detailed Solution for Test: Biology - 11 - Question 80
ELISA based on the principle of Antigen - Antibody Interaction
Explanation:
ELISA (Enzyme-Linked Immunosorbent Assay) is a commonly used laboratory technique for detecting and quantifying substances such as proteins, hormones, and antibodies. It is based on the principle of antigen-antibody interaction. Here is a detailed explanation of how ELISA works:
- Antigen: An antigen is a substance that can stimulate an immune response in the body. In ELISA, the antigen of interest is immobilized or attached to a solid surface, such as a microplate. This can be done by directly coating the antigen or by capturing it using specific antibodies.
- Antibody: Antibodies are proteins produced by the immune system in response to the presence of antigens. In ELISA, specific antibodies that recognize and bind to the antigen of interest are used. These antibodies are labeled with an enzyme, such as horseradish peroxidase (HRP), for detection purposes.
- Binding: During the ELISA process, the sample containing the antigen is added to the microplate coated with the specific antibody. If the antigen is present in the sample, it will bind to the immobilized antibody, forming an antigen-antibody complex.
- Washing: After a specific incubation period, the microplate is washed to remove any unbound substances and to reduce nonspecific binding.
- Enzyme Detection: A substrate solution containing a colorless substrate specific for the enzyme label (e.g., HRP) is added to the microplate. If the antigen-antibody complex is present, the enzyme label will catalyze a reaction with the substrate, resulting in the formation of a colored product.
- Quantification: The color intensity is measured using a spectrophotometer, and the amount of antigen present in the sample is determined by comparing the absorbance values to a standard curve generated using known concentrations of the antigen.
In summary, ELISA