Biology: Topic-wise Test- 7 - NEET MCQ

The bioactive agent Cyclosporin-A, which is commonly used as an immunosuppressive drug, is produced by the fungus Trichoderma polysporum. Here is a detailed explanation:
1. Cyclosporin-A:
- Cyclosporin-A is a potent immunosuppressive drug that is widely used in organ transplantation to prevent rejection.
- It is also used to treat autoimmune diseases such as rheumatoid arthritis and psoriasis.
2. Production by Fungus:
- Cyclosporin-A is produced by a specific strain of the fungus Trichoderma polysporum.
- This fungus is known for its ability to produce secondary metabolites with pharmaceutical importance.
3. Other Options:
- Monascus purpureus is a fungus used in the production of red yeast rice, which is used as a dietary supplement.
- Aspergillus niger is a common fungus used in the production of various enzymes and organic acids.
- Propionibacterium shermanii is a bacterium used in the production of propionic acid and Swiss cheese.
4. Conclusion:
- Among the given options, Trichoderma polysporum is the fungus that produces Cyclosporin-A.
- Its immunosuppressive properties make it valuable in the field of medicine for preventing organ rejection and treating autoimmune diseases.

BOD (Biochemical Oxygen Demand) is a measure of:
- Rate of uptake of organic matter by microbes: BOD is a measure of the amount of oxygen required by microorganisms to decompose organic matter in water. Microbes utilize oxygen during the decomposition process, and the rate at which they consume oxygen can be quantified as BOD.
- Presence of organic matter: BOD is used as an indicator of the amount of organic pollutants present in water. Higher BOD values suggest a higher concentration of organic matter, indicating the presence of pollutants that can negatively impact water quality.
- Both 1 and 2: BOD is a measure that encompasses both the rate of uptake of organic matter by microbes and the presence of organic pollutants in water. It provides information about the biological activity and the pollution level in water bodies.
- Organic and industrial matter: BOD measurement primarily focuses on the decomposition of organic matter, including both natural and anthropogenic sources. Industrial waste can contribute to BOD levels in water bodies, making BOD a useful parameter for assessing the impact of industrial activities on water quality.
In conclusion, BOD is a measure that encompasses the rate of uptake of organic matter by microbes and indicates the presence of organic pollutants, including those from industrial sources. Therefore, the correct answer is C: both 1 and 2.

Labiatae are a family of flowering plants commonly known as the mint or deadnettle family. Many of the plants are aromatic in all parts and include widely used culinary herbs, such as basil, mint, rosemary, sage, savory, marjoram, oregano, hyssop, thyme, lavender, and perilla. Some species are shrubs, trees (such as teak), or, rarely, vines. Many members of the family are widely cultivated, not only for their aromatic qualities, but also their ease of cultivation, since they are readily propagated by stem cuttings.[citation needed] Besides those grown for their edible leaves, some are grown for decorative foliage, such as Coleus. Others are grown for seed, such as Salvia hispanica (chia), or for their edible tubers, such as Plectranthus edulis, Plectranthus esculentus, Plectranthus rotundifolius, and Stachys affinis (Chinese artichoke).
The family has a cosmopolitan distribution.The enlarged Lamiaceae contain about 236 genera[5] and have been stated to contain 6,900 to 7,200 species, but the World Checklist lists 7,534. The largest genera are Salvia (900), Scutellaria (360), Stachys (300), Plectranthus (300), Hyptis (280), Teucrium (250), Vitex (250), Thymus (220), and Nepeta (200).Clerodendrum was once a genus of over 400 species, but by 2010, it had been narrowed to about 150.
The family has traditionally been considered closely related to the Verbenaceae; in the 1990s, phylogenetic studies suggested that many genera classified in the Verbenaceae should be classified in the Lamiaceae or to other families in the order Lamiales

Adventive embryony in Angiosperms:
Adventive embryony is a phenomenon in which embryos develop from cells other than the fertilized egg. In angiosperms, adventive embryony can occur through various mechanisms. However, in this specific question, adventive embryony is specifically asked to develop from diploid nucellar cells asexually (option A).
Here is a detailed explanation of the answer:
1. Angiosperm embryogenesis:
Before understanding adventive embryony, it is important to understand the normal embryogenesis process in angiosperms:
- Embryogenesis in angiosperms typically starts with the fertilization of the egg cell by the pollen tube, resulting in the formation of a zygote.
- The zygote then undergoes several divisions to form an embryo, which is enclosed within the embryo sac.
- The embryo sac contains various cells, including the egg cell, synergids, antipodal cells, and central cell.
2. Adventive embryony:
Adventive embryony is a type of embryogenesis that occurs without fertilization of the egg cell. It involves the development of embryos from cells other than the zygote.
3. Development from diploid nucellar cells:
In angiosperms, one of the mechanisms of adventive embryony is the development of embryos from diploid nucellar cells asexually. Nucellar cells are the cells present in the nucellus, a part of the ovule.
- Nucellar cells are typically haploid, but in some cases, they can be diploid.
- When diploid nucellar cells undergo asexual development, they can give rise to adventive embryos without the need for fertilization.
4. Other mechanisms of adventive embryony:
Apart from the development from diploid nucellar cells, adventive embryony can also occur through other mechanisms:
- Development from haploid nucellar cells asexually.
- Development from any cell of the embryo sac asexually.
- Development from the megaspore mother cell (MMC) sexually.
5. Importance of adventive embryony:
Adventive embryony plays a significant role in angiosperms, as it provides a means of asexual reproduction and can contribute to the production of more offspring without the need for pollination and fertilization.
In conclusion, adventive embryony in angiosperms can develop from diploid nucellar cells asexually. This mechanism allows for the formation of embryos without fertilization, leading to asexual reproduction in certain angiosperm species.

Most common type of Tetrad in Angiosperms are:
Tetra hedral Tetrads
- Tetra hedral tetrads are the most common type of tetrad found in angiosperms.
- These tetrads consist of four microspores or megaspores arranged in a tetrahedral shape.
- The tetrahedral arrangement gives rise to a 3-dimensional structure.
- This type of tetrad is characteristic of angiosperms, which are flowering plants.
- The tetrahedral arrangement is thought to provide mechanical support and protection to the developing spores.
- It also allows for efficient packing of spores within the anther or ovule.
- Tetra hedral tetrads are found in both male (microspores) and female (megaspores) reproductive structures of angiosperms.
- This type of tetrad is important for the successful development and dispersal of spores in angiosperms.
In conclusion, the most common type of tetrad in angiosperms is the tetra hedral tetrad, which consists of four microspores or megaspores arranged in a tetrahedral shape. This tetrad arrangement is characteristic of angiosperms and plays a crucial role in the development and dispersal of spores.

Pollen embryo sacs are also called Nemec Phenamenon, as Nemec discovered them for the first time. According to Nemec, pollen embryo sacs are produced by the repeated divisions of vegetative nucleus while the generative nucleus degenerates.

Metaxenia Related to
Metaxenia is a phenomenon in which the characteristics of the male parent influence the characteristics of the seed coat of a plant. It refers to the effect of the male gamete on the seed coat development. Let's explore the relationship between metaxenia and the given options:
Option A: Micropropagation
- Micropropagation refers to the process of growing plants from small plant parts, such as tissue culture or meristem culture.
- There is no direct relationship between metaxenia and micropropagation. Metaxenia is not specifically related to the propagation method used.
Option B: Agamospermy
- Agamospermy is a form of asexual reproduction in plants where seeds are formed without fertilization.
- Metaxenia can occur in both sexual and asexual reproduction, so there is no direct relationship between metaxenia and agamospermy.
Option C: Effect of male gamete over seed coat of plant
- This option accurately describes the relationship between metaxenia and the effect of the male gamete on the seed coat development.
- Metaxenia occurs when the characteristics of the male parent influence the seed coat of the plant.
Option D: Sporophytic Budding
- Sporophytic budding refers to a type of asexual reproduction where a new individual grows from a bud on the parent plant.
- There is no direct relationship between metaxenia and sporophytic budding. Metaxenia is not specifically related to the method of asexual reproduction.
Therefore, the correct answer is option C: Effect of male gamete over seed coat of plant. Metaxenia is related to the influence of the male gamete on the development of the seed coat in plants.

In Pinus generally leaf and roots are diploid ...so 2n=24....so the endosperm that is n will be..n=12...that is half of the diploid cell.

Formation of Free Nuclear Division:
Free nuclear division refers to the division of the nucleus without the corresponding division of the cytoplasm. It occurs in certain plant tissues during specific developmental stages.
Options:
A: Gametes
B: Endosperms
C: Flower
D: Embryo
Explanation:
Free nuclear division occurs during the formation of endosperms. Endosperm is a tissue found in the seeds of flowering plants. It provides nourishment to the developing embryo and is formed by the fusion of a sperm cell with two polar nuclei in a process called double fertilization.
During endosperm development, the nucleus undergoes multiple rounds of division without the formation of cell walls. This results in the formation of a multinucleate mass of cytoplasm, which eventually becomes the endosperm tissue. The free nuclear divisions in the endosperm are crucial for the proper development and nutrient storage in the seed.
Conclusion:
The correct answer is B: Endosperms. Free nuclear division occurs during the formation of endosperms in plants.

Yes, polygonum type of embryo sac is 8 nucleate. it has 3 nuclei of antipodal cells, 2 nuclei of synergids, 1 nucleus of the egg cell and the rest are the 2 polar nuclei.

Explanation:
To determine which part might have given rise to diploid plants after culturing the anther of a plant, we need to understand the process of anther culture and the role of different parts of the anther.
Anther culture involves isolating and culturing the anther, which contains pollen grains. During this process, different parts of the anther can give rise to different types of plants. Let's analyze the options given:
A: Vegetative cell of pollen
- The vegetative cell of pollen is responsible for producing the pollen tube during fertilization.
- It does not contribute to the formation of diploid plants in anther culture.
B: Cells of anther wall
- The cells of the anther wall are somatic cells that surround the developing pollen grains.
- These cells have the potential to undergo dedifferentiation and redifferentiation, allowing them to give rise to diploid plants.
- Therefore, the cells of the anther wall have the ability to produce diploid plants in anther culture.
C: Generative cell of pollen
- The generative cell of pollen is responsible for giving rise to the sperm cells (male gametes) during fertilization.
- It does not directly contribute to the formation of diploid plants in anther culture.
D: Intine of pollen wall
- The intine of the pollen wall is the inner layer of the pollen grain wall.
- It provides protection and support to the developing pollen grain but does not have the ability to give rise to diploid plants.
Conclusion:
Based on the above analysis, the cells of the anther wall (option B) are the most likely to give rise to diploid plants after culturing the anther of a plant.

Nucellar embryo is:
- Apomictic diploid.
Detailed explanation:
- The term "nucellar embryo" refers to an embryo that develops from the nucellus, a tissue found in the ovule of certain plants.
- Nucellar embryos are formed through a type of reproduction called apomixis.
- Apomixis is a form of asexual reproduction in plants where seeds are produced without fertilization.
- In apomixis, the embryo develops from the diploid cells of the nucellus, instead of being formed through the fusion of gametes.
- As a result, nucellar embryos are genetically identical to the parent plant and are therefore diploid.
- The term "amphimictic" refers to sexual reproduction, where the embryo is formed through the fusion of gametes.
- The term "haploid" refers to having a single set of chromosomes, while "diploid" refers to having two sets of chromosomes.
- Since nucellar embryos are formed through apomixis and are diploid, the correct answer is apomictic diploid (B).

Synthesis of Sporopollenin
Sporopollenin, a complex biopolymer, is an important component of the outer layer (exine) of pollen grains and spores. The synthesis of sporopollenin occurs in two locations: the tapetum and the cytoplasm of the young spores. It is derived from oxidative polymerization of carotenoids.
Explanation:
The synthesis of sporopollenin involves the following steps:
1. Formation of primexine: In the tapetum, a layer of cells surrounding the developing pollen grains or spores, carotenoids are oxidatively polymerized to form primexine. Primexine serves as a template for the subsequent deposition of sporopollenin.
2. Deposition of sporopollenin: The primexine template is then transported to the cytoplasm of the young spores. Inside the cytoplasm, sporopollenin precursors are synthesized and deposited onto the primexine template. The deposition process involves the gradual accumulation of sporopollenin layers, leading to the formation of the mature exine.
3. Mature exine formation: As sporopollenin layers continue to accumulate, the exine becomes thicker and more resistant to environmental stresses. The mature exine provides protection to the developing pollen grains or spores during their dispersal and germination.
Conclusion:
In summary, sporopollenin is synthesized through the oxidative polymerization of carotenoids. This process occurs in both the tapetum and the cytoplasm of the young spores. Sporopollenin plays a crucial role in the development of pollen grains and spores, providing them with structural integrity and protection.

Propagation of cultivated varieties of Musa mainly involves the use of suckers. Here is a detailed explanation:
Propagation of cultivated varieties of Musa:
- Musa is a genus of flowering plants that includes banana and plantain species.
- Propagation refers to the process of reproducing plants from existing ones, ensuring the continuation of desired traits.
- Cultivated varieties of Musa are propagated using various methods, but the most common one is through suckers.
Explanation:
- Suckers: Suckers are small shoots or shoots that arise from the base of the banana plant, near the underground rhizome.
- Suckers are genetically identical to the parent plant, preserving the desired traits of the cultivated variety.
- They can be detached from the parent plant and replanted to establish new plants.
- Suckers provide a quicker and more reliable method of propagation compared to other options.
- They also ensure the uniformity and consistency of the cultivated variety.
Other options:
- Corrm: Corrm is not a recognized term in the context of Musa propagation. It is not relevant to cultivated varieties of Musa.
- Seed: While some wild species of Musa can produce seeds, cultivated varieties rarely produce viable seeds. If seeds are obtained, they do not guarantee the replication of desired traits.
- Stem cuttings: Stem cuttings can be used for Musa propagation, but they are less commonly used compared to suckers. Cuttings taken from the stem of a mature plant can be rooted and grown into new plants. However, this method may not always produce plants with the desired traits.

In summary, the most commonly used method for propagating cultivated varieties of Musa is through suckers. Suckers ensure genetic uniformity, preserve desired traits, and provide a reliable and efficient means of propagation.

The Role of Secretory Tapetum in the Deposition of Sporopollenin Granules (Ubisch Bodies or Orbicules)
Introduction:
Tapetum is a layer of cells found in the anther of flowering plants. It plays a crucial role in pollen development and serves as a nutrient source for pollen grains. Tapetum can be classified into two main types: amoeboid tapetum and secretory tapetum.
Answer:
The type of tapetum that plays a role in the deposition of sporopollenin granules, known as Ubisch bodies or orbicules, is secretory tapetum (B).
Explanation:
Here is a detailed explanation of why secretory tapetum is involved in the deposition of Ubisch bodies or orbicules:
1. Secretory Tapetum: Secretory tapetum is characterized by the production and secretion of various substances, including lipids, proteins, and sporopollenin. It is responsible for providing essential nutrients and materials required for the development of pollen grains.
2. Sporopollenin Granules: Sporopollenin is a complex biopolymer found in the outer layer of pollen grains and spores. It is highly resistant to environmental factors and provides protection to pollen grains during their development and dispersal.
3. Deposition of Ubisch Bodies or Orbicules: Ubisch bodies or orbicules are specialized sporopollenin granules found in the tapetum. They are synthesized and deposited in the tapetum cells before being transferred to the pollen grain exine (outer wall).
4. Role of Secretory Tapetum: Secretory tapetum plays a crucial role in the deposition of Ubisch bodies or orbicules by:
- Synthesizing sporopollenin granules within its cells.
- Accumulating and storing the sporopollenin granules.
- Secretion of the sporopollenin granules into the anther locule, where they come in contact with developing pollen grains.
- Facilitating the transfer of sporopollenin granules from the tapetum to the pollen grain exine.
5. Function of Ubisch Bodies or Orbicules: Ubisch bodies or orbicules have various functions, such as:
- Providing structural integrity to the pollen grain exine.
- Acting as a physical barrier against desiccation and environmental stress.
- Enhancing pollen grain viability and fertility.
In conclusion, secretory tapetum plays a vital role in the deposition of sporopollenin granules, including Ubisch bodies or orbicules. These specialized structures contribute to the development and protection of pollen grains during their maturation and dispersal.

Sowing is done by the seed which is the reproductive part of plant not the vegetative part.

Explanation:

During grafting, rootstock is generally derived from a plant. This means that the rootstock, which is the lower part of the graft, is taken from a different plant and joined to the scion, which is the upper part of the graft. The rootstock is chosen based on specific characteristics and traits that are desirable in the resulting grafted plant.

Reasons for selecting rootstock:

• Efficient in water and mineral absorption: The rootstock is selected for its ability to efficiently absorb water and minerals from the soil. This ensures that the grafted plant has a strong and healthy root system.


• Resistance to diseases: The rootstock is often chosen for its resistance to specific diseases or pests. This helps protect the grafted plant from potential infections and improves its overall health and productivity.


• Growth of strong and healthy branches: The rootstock can also influence the growth and development of the branches of the grafted plant. By selecting a rootstock that promotes strong and healthy branch growth, the overall structure and vigor of the grafted plant can be enhanced.

Therefore, the correct answer is D: all of these. The rootstock selection plays a crucial role in the success and performance of the grafted plant.

Apospory:
Formation of embryo from egg of an embryo sac developed directly from a cell of nucellus.
Apospory refers to the development of an embryo directly from a cell of the nucellus, bypassing the normal process of embryo sac formation. It is a type of asexual reproduction in plants.
Explanation:
Apospory is a form of apomixis, which is the production of seeds without fertilization. In apospory, the embryo sac develops directly from a cell of the nucellus, rather than from the megaspore mother cell.
Here is the detailed explanation of each option:
A. Formation of embryo from egg of an embryo sac developed directly from megaspore mother cell: This option does not accurately describe apospory because apospory involves the development of an embryo sac from a cell of the nucellus, not the megaspore mother cell.
B. Formation of embryo from egg of an embryo sac developed directly from a cell of nucellus: This option accurately describes apospory. The embryo sac is formed directly from a cell of the nucellus, and the embryo develops from the egg within this embryo sac.
C. Formation of embryo from nucellus: This option does not accurately describe apospory because apospory involves the development of an embryo sac from a cell of the nucellus, not the direct formation of an embryo from the nucellus itself.
D. Formation of embryo from integument: This option does not accurately describe apospory because apospory involves the development of an embryo sac from a cell of the nucellus, not the integument.
Therefore, the correct answer is B: Formation of embryo from egg of an embryo sac developed directly from a cell of nucellus.

SCP Term Related to a Yeast:
- SCP-1780: SCP-1780 is a Euclid-class SCP that refers to a colony of anomalous yeast organisms. These yeast organisms can rapidly multiply and consume any organic matter they come into contact with, including living organisms. They have the ability to break down complex substances into simpler forms, leading to their classification as a self-sustaining biological SCP.
- SCP-1861: SCP-1861 is a Keter-class SCP that involves a fungal infection caused by an anomalous strain of yeast. This infection affects humans and other living organisms, leading to various physical and psychological effects. It is highly contagious and poses a significant threat to containment.
- SCP-2354: SCP-2354 is a Safe-class SCP that refers to a strain of yeast capable of producing a substance known as "SCP-2354-A." This substance has potent antimicrobial properties and can be used to treat various infectious diseases. However, it also has the potential for misuse and must be carefully controlled.
SCP Term Related to a Prion:
- SCP-008: SCP-008 is a Euclid-class SCP that is a highly infectious prion. It causes a disease known as "SCP-008-1," which leads to rapid zombification in infected individuals. The prion can be transmitted through bodily fluids and poses a significant risk to containment.
- SCP-019: SCP-019 is a Safe-class SCP that involves a prion-infected sculpture. When exposed to living organisms, the prions within the sculpture can cause rapid degeneration and death. It is essential to handle SCP-019 with extreme caution to prevent any accidental infection.
SCP Term Related to a Big Plant:
- SCP-789-J: SCP-789-J is a Euclid-class SCP that refers to a giant sentient cactus. It possesses anomalous properties, including the ability to communicate with Foundation personnel and exhibit a playful personality. The cactus requires regular watering and sunlight to maintain its health.
- SCP-317: SCP-317 is a Safe-class SCP that involves a species of large carnivorous plants. These plants have the ability to attract and capture prey using their unique scent and appearance. They are kept in a controlled environment to prevent accidental harm to personnel.
- SCP-328: SCP-328 is a Euclid-class SCP that resembles a large, parasitic tree. It has the ability to drain the life force of nearby living organisms, causing them to wither and die. The tree requires constant monitoring to prevent it from spreading and causing harm.

Small Proteins produced by vertebrate cells naturally and in response to viral infections inhibiting viral multiplication are known as Interferon.
Interferons are a group of signaling proteins that are released by host cells in response to the presence of viruses. They play a crucial role in the innate immune response by inhibiting viral replication and modulating the immune system. Here is a detailed explanation of Interferons:
1. Definition:
- Interferons are small proteins that are naturally produced by vertebrate cells and are part of the body's defense mechanism against viral infections.
2. Function:
- They interfere with viral replication by inhibiting the synthesis of viral proteins and preventing the virus from spreading to neighboring cells.
- Interferons also activate immune cells, such as natural killer cells and macrophages, which help in the destruction of infected cells.
- They enhance the expression of major histocompatibility complex (MHC) molecules on the surface of cells, which aids in the recognition and elimination of infected cells by cytotoxic T cells.
3. Types of Interferons:
- There are three main types of interferons: alpha, beta, and gamma.
- Interferon-alpha and interferon-beta are produced by most cells in response to viral infections, while interferon-gamma is mainly produced by immune cells.
4. Mechanism of Action:
- Interferons bind to specific receptors on the surface of neighboring cells, triggering a signaling cascade that activates antiviral genes.
- This leads to the production of various proteins that inhibit viral replication and enhance the immune response.
5. Therapeutic Applications:
- Interferons have been used therapeutically to treat viral infections, such as hepatitis B and C, and certain types of cancer.
- They are also being investigated for their potential role in the treatment of COVID-19.
In conclusion, Interferons are small proteins produced by vertebrate cells in response to viral infections. They play a vital role in inhibiting viral multiplication and modulating the immune response.

Bt cotton is a genetically modified variety of cotton that has been widely cultivated. The prefix "Bt" stands for Bacillus thuringiensis, which is a type of bacteria that produces a toxin harmful to certain pests. Here's a detailed explanation of the meaning of the Bt prefix:
Bacillus thuringiensis:
- Bacillus thuringiensis is a naturally occurring soil bacterium that produces proteins toxic to certain insects.
- This bacterium has been used for many years as a biological pesticide in agriculture to control pests.
Endotoxin gene:
- The Bt cotton variety is genetically modified to carry a specific gene from Bacillus thuringiensis.
- This gene allows the cotton plants to produce a protein that is toxic to specific pests, such as the bollworm and pink bollworm.
- The protein is only toxic to these pests and does not harm other organisms, including humans.
Biotechnology:
- Bt cotton is produced using biotechnology techniques, which involve the manipulation of an organism's genetic material.
- Restriction enzymes and ligases are used to cut and join DNA segments, allowing the insertion of the endotoxin gene into the cotton plant's genome.
- This genetic modification enables the cotton plants to produce the toxin and protect themselves against insect pests.
Advantages of Bt cotton:
- Bt cotton has been widely adopted by farmers due to its effectiveness in controlling pests.
- It reduces the need for chemical insecticides, leading to a decrease in environmental pollution and potential harm to farmers' health.
- Bt cotton also increases crop yields by minimizing the damage caused by insect pests.
- The cultivation of Bt cotton has contributed to the reduction in pesticide use and increased profitability for farmers in many regions.
In conclusion, the prefix Bt in Bt cotton refers to the genetic modification of the cotton plant to carry an endotoxin gene from Bacillus thuringiensis. This modification allows the plant to produce a protein toxic to specific pests, providing effective pest control and reducing the reliance on chemical insecticides. The cultivation of Bt cotton has brought numerous benefits to farmers and the environment.

Viability Testing of Seeds
There are various methods to test the viability of seeds, including the use of chemicals. In this case, the chemical that can be used to test the viability of the seed is "T T C." Let's discuss this in detail:
1. Viability Testing:
- Viability testing is performed to determine whether a seed is capable of germination and producing a viable plant.
- It is particularly important for studying the longevity and dormancy of seeds.
2. Importance of Viability Testing:
- Viability testing helps in understanding the lifespan and dormancy period of seeds.
- It can provide insights into the survival strategies of plants under different conditions.
- Viability testing is crucial for conservation and restoration efforts, as it helps in selecting seeds with the highest chances of successful germination.
3. Chemical Test for Viability:
- One of the chemicals that can be used to test the viability of seeds is "T T C."
- T T C stands for 2,3,5-triphenyl tetrazolium chloride, which is a redox indicator commonly used to assess seed viability.
- This chemical is colorless and water-soluble but gets converted to a red formazan dye in the presence of dehydrogenase enzymes found in living cells.
- If the seed is viable and contains living cells, the T T C solution will turn red, indicating the presence of active enzymes and hence, viability.
4. Other Methods for Seed Viability Testing:
- Apart from chemical testing, there are other methods to test seed viability, including:
- Germination tests: Seeds are placed under favorable conditions to observe their ability to sprout and develop into seedlings.
- Tetrazolium chloride staining: Similar to T T C, this method uses tetrazolium chloride to stain viable tissues.
- Electrical conductivity tests: Measures the leakage of electrolytes from the seeds, which indicates their viability.
- DNA-based methods: Molecular techniques can be employed to assess the genetic material and viability of seeds.
In conclusion, the chemical "T T C" (2,3,5-triphenyl tetrazolium chloride) can be used to test the viability of seeds. Viability testing is crucial for understanding the longevity and dormancy of seeds and plays a significant role in conservation and restoration efforts.

Agave vegetative reproduction:
Agave plants are known for their ability to reproduce vegetatively, meaning they can generate new plants without the need for seeds or sexual reproduction. This process is carried out through bulbils.
What are bulbils?
Bulbils are small, bulb-like structures that form on the stem or in the leaf axils of the Agave plant. They serve as a means of asexual reproduction and are responsible for generating new offspring plants.
Process of vegetative reproduction:
The vegetative reproduction in Agave through bulbils involves the following steps:
1. Bulbil formation: Bulbils develop from the stem or in the leaf axils of the Agave plant. They are small and bulb-shaped structures that contain all the necessary genetic material for the formation of a new plant.
2. Maturation: As the bulbils mature, they develop roots and shoots, preparing themselves for detachment from the parent plant.
3. Detachment: Once mature, the bulbils detach from the parent plant either naturally or through external factors such as wind, rain, or animal movement.
4. Dispersal: The detached bulbils are then dispersed to new locations, where they have the potential to grow into new Agave plants. This allows Agave plants to colonize different areas and expand their population.
5. Growth and development: When the bulbils settle in suitable conditions, they establish roots and shoots, eventually growing into mature Agave plants.
Advantages of vegetative reproduction in Agave:
- Efficient reproduction: Vegetative reproduction allows Agave plants to produce offspring without the need for pollination or the production of seeds. This process is faster and more efficient than sexual reproduction.
- Genetic similarity: As bulbils are formed from the parent plant, they carry the exact genetic material, resulting in offspring that are genetically identical to the parent. This ensures the preservation of desirable traits.
- Adaptation to harsh environments: Agave plants are commonly found in arid and semiarid regions. Vegetative reproduction through bulbils allows them to colonize new areas and adapt to harsh environmental conditions more effectively.
- Increased population: By producing multiple bulbils, Agave plants can generate a higher number of offspring, leading to an increase in population size.
Conclusion:
Agave plants utilize bulbils for their vegetative reproduction, allowing them to efficiently produce offspring without the need for seeds or sexual reproduction. This process provides advantages such as genetic similarity, adaptation to harsh environments, and increased population size.

Explanation:
The term "LAB" refers to Lactic Acid Bacteria, which is a type of bacteria commonly used in various applications.
LAB can help in:
- Checking disease: LAB is commonly used in medical and diagnostic laboratories to identify and diagnose various diseases. It can be used to detect the presence of specific bacteria or viruses in a patient's sample, aiding in the diagnosis and treatment of diseases.
- Fermentation: LAB plays a crucial role in the fermentation process. It is used to convert sugars into lactic acid, which helps in preserving and flavoring various food products. LAB is commonly used in the production of yogurt, cheese, sauerkraut, pickles, and other fermented foods.
- Roquefort cheese making: LAB is specifically used in the production of Roquefort cheese. It helps in the development of the cheese's unique flavor and texture by contributing to the fermentation process.
- None of these: This option is incorrect as LAB can indeed help in checking disease, fermentation, and Roquefort cheese making.
Therefore, the correct answer is C. "Roquefort cheese making."

Pseudomonas putida: A Detailed Explanation
Pseudomonas putida is a species of bacteria that belongs to the Pseudomonas genus. It is a Gram-negative, rod-shaped bacterium that is commonly found in soil and freshwater environments. This bacterium has several unique characteristics and plays various roles in the ecosystem.
Key Points:
- Pseudomonas putida: A species of bacteria belonging to the Pseudomonas genus.
- Gram-negative: The bacterium has a cell wall structure that stains pink during the Gram staining procedure.
- Rod-shaped: Pseudomonas putida has a cylindrical shape.
- Environmental distribution: It is commonly found in soil and freshwater environments.
- Ecosystem role: Pseudomonas putida plays a crucial role in bioremediation, as it has the ability to degrade various pollutants and contaminants.
- Biodegradation capabilities: This bacterium can degrade a wide range of organic compounds, including aromatic hydrocarbons, pesticides, and toxic chemicals.
- Plant interactions: Pseudomonas putida can establish beneficial relationships with plants. It can promote plant growth, enhance nutrient uptake, and provide protection against pathogens.
- Industrial applications: Due to its biodegradation capabilities, Pseudomonas putida is used in various industries for the treatment of wastewater, the production of biofuels, and the removal of pollutants.
- Research interest: Scientists are studying Pseudomonas putida extensively to understand its genetic and metabolic capabilities, which can potentially be harnessed for various applications.
In conclusion, Pseudomonas putida is a versatile bacterium with significant environmental and industrial importance. Its ability to degrade pollutants and establish beneficial interactions with plants makes it a valuable asset in various fields. Ongoing research continues to explore its potential applications, making it an exciting area of study.

Plague is caused by:
- Yersinia pestis: Yersinia pestis is the bacterium responsible for causing plague. It is a Gram-negative, rod-shaped bacterium that primarily affects rodents and is transmitted to humans through fleas.


Explanation:
Plague, also known as the Black Death, is a severe infectious disease caused by the bacterium Yersinia pestis. It has been responsible for several major pandemics throughout history, including the Black Death in the 14th century, which decimated the population of Europe.
Here is a detailed explanation of each option and why Yersinia pestis is the correct answer:
- Trichinella pestis: Trichinella is a genus of parasitic roundworms that causes the disease trichinosis. Trichinosis is primarily acquired by consuming raw or undercooked meat infected with Trichinella larvae, not by fleas or rodents. Therefore, Trichinella pestis is not the correct answer for the cause of plague.
- Leishmania donovani: Leishmania donovani is a parasite that causes a tropical disease called visceral leishmaniasis or kala-azar. It is transmitted to humans through the bite of infected sandflies, not through fleas or rodents. Therefore, Leishmania donovani is not the correct answer for the cause of plague.
- Corynebacterium rependonicum: Corynebacterium rependonicum is a species of bacteria that is mainly associated with infections in horses and other animals. It does not cause plague in humans. Therefore, Corynebacterium rependonicum is not the correct answer for the cause of plague.
- Yersinia pestis: Yersinia pestis is the correct answer for the cause of plague. It is a bacterium that primarily affects rodents, especially rats, and is transmitted to humans through fleas that have bitten infected animals. Yersinia pestis can cause three forms of plague in humans: bubonic, septicemic, and pneumonic. Bubonic plague is the most common form and is characterized by swollen lymph nodes (buboes). Septicemic plague occurs when the bacteria spread to the bloodstream, and pneumonic plague affects the lungs and can be transmitted from person to person through respiratory droplets.
In conclusion, the correct answer for the cause of plague is Yersinia pestis, a bacterium transmitted to humans through fleas that have bitten infected rodents.

Terramycin is obtained from Streptomyces rimosus.
Explanation:
Terramycin is an antibiotic medication that is used to treat various bacterial infections. It belongs to the tetracycline group of antibiotics. The tetracyclines are produced by certain strains of soil bacteria called Streptomyces.
Key Points:
- Terramycin is obtained from Streptomyces rimosus, a species of bacteria.
- Streptomyces rimosus is known for its ability to produce the antibiotic Terramycin.
- Streptomyces rimosus is a Gram-positive bacteria that forms filamentous structures called mycelia.
- The mycelia of Streptomyces rimosus contain specialized structures called spores, which are responsible for the production of Terramycin.
- The spores of Streptomyces rimosus are harvested and processed to extract Terramycin, which is then purified and formulated into various dosage forms for medical use.
Conclusion:
Terramycin is obtained from the bacteria Streptomyces rimosus. The bacteria produce the antibiotic through the formation of spores, which are then processed to extract Terramycin.

Characteristics of Clostridium botulinum:
1. It inhabits soils around the world: This is a characteristic feature of Clostridium botulinum. The bacterium is commonly found in soil, sediments, and aquatic environments worldwide.
2. Its spores grow in nutrient-rich medium: Clostridium botulinum can form spores that are capable of surviving in harsh conditions, including nutrient-rich environments. This allows the bacterium to persist and potentially cause infection when conditions are favorable.
3. Vomiting, constipation, paralysis of eyes & throat are common symptoms of botulism: Botulism, caused by the toxin produced by Clostridium botulinum, is characterized by symptoms such as vomiting, constipation, blurred vision, drooping eyelids, difficulty swallowing, and muscle weakness. These symptoms are a result of the neurotoxin affecting the nervous system.
4. Bacterium cannot live without oxygen: This statement is not a characteristic feature of Clostridium botulinum. In fact, Clostridium botulinum is an anaerobic bacterium, meaning it can survive and grow in the absence of oxygen. It thrives in low-oxygen environments such as the soil and the gastrointestinal tract.
Therefore, the correct answer is A: It inhabits soils around the world.

Why Escherichia coli is extensively used in biological research:
1. Easy to handle: Escherichia coli, commonly known as E. coli, is a bacterium that is relatively easy to handle in the laboratory setting. It has simple growth requirements and can be easily manipulated for various experimental purposes.
2. Easily available: E. coli is a commonly found bacterium in the environment, especially in the intestines of humans and other animals. It can be easily obtained from various sources, such as fecal samples or commercially available strains.
3. Easily cultured in the laboratory: E. coli can be easily cultured in the laboratory using standard microbiological techniques. It grows quickly and can be maintained on simple nutrient agar or broth media. This allows researchers to obtain large quantities of the bacterium for experiments.
4. Genetic tractability: E. coli has a well-characterized and easily manipulated genome. It has been extensively studied and many genetic tools and techniques have been developed for its analysis. This makes it an ideal model organism for studying various biological processes, including gene expression, DNA replication, and protein synthesis.
5. Similarity to higher organisms: Despite being a bacterium, E. coli shares many similarities with higher organisms, including humans. It possesses many of the same fundamental cellular processes and molecular mechanisms. Studying E. coli can provide valuable insights into the functioning of more complex organisms.
In conclusion, Escherichia coli is extensively used in biological research because of its ease of handling, availability, ease of cultivation in the laboratory, genetic tractability, and its similarity to higher organisms. These characteristics make it a versatile and widely used model organism for various scientific studies.

Why is dissolved oxygen removed from boiler feed water?
There are several reasons why dissolved oxygen is removed from boiler feed water. These include:
1. Prevention of microorganism growth:
- Dissolved oxygen can promote the growth of microorganisms such as bacteria and algae in the boiler feed water.
- Microorganism growth can lead to biofouling and the formation of biofilms on heat transfer surfaces.
- This can reduce heat transfer efficiency, increase corrosion rates, and result in the formation of deposits.
2. Prevention of corrosion:
- Dissolved oxygen in the water can cause corrosion in the boiler and other metal components.
- Oxygen reacts with the metal surface to form iron oxide (rust), which weakens the metal and can lead to leaks or equipment failure.
- Removing dissolved oxygen helps to minimize the corrosive effects and extend the lifespan of the boiler system.
3. Prevention of bubble formation:
- Dissolved oxygen can also contribute to the formation of bubbles or foam in the boiler.
- These bubbles can interfere with the proper circulation of water and steam, leading to reduced heat transfer and potential damage to equipment.
4. Maintenance of boiler efficiency:
- The presence of dissolved oxygen in boiler feed water can reduce the efficiency of the boiler system.
- Oxygen can react with chemicals in the water, leading to the formation of scale and deposits on heat transfer surfaces.
- This reduces heat transfer efficiency, increases energy consumption, and decreases overall boiler performance.
In conclusion, the removal of dissolved oxygen from boiler feed water is essential to prevent microorganism growth, corrosion, bubble formation, and loss in boiler efficiency. By eliminating dissolved oxygen, the boiler system can operate more efficiently, reduce the risk of equipment damage, and prolong its lifespan.