Biology Mock Test- 5 - Class 10 MCQ

Artificial Ripening of Fruits

• Ethylene: Ethylene is a plant hormone that plays a crucial role in the ripening of fruits. It is commonly used in the artificial ripening process to accelerate the ripening of fruits such as bananas, tomatoes, and mangoes.


• Mechanism: Ethylene works by triggering a series of biochemical reactions in fruits that lead to the softening, color changes, and development of characteristic flavors associated with ripening.


• Application: Fruits can be exposed to ethylene gas in controlled environments to speed up the ripening process. This method is commonly used in commercial settings to ensure fruits reach optimal ripeness before being sold to consumers.


• Regulation: The use of ethylene for artificial ripening is regulated to ensure the safety of consumers. The concentration of ethylene gas, exposure time, and temperature conditions are carefully monitored to prevent over-ripening or spoilage of fruits.


• Benefits: Artificial ripening using ethylene allows for better control over the ripening process, ensuring that fruits are available to consumers at the desired stage of ripeness. It also helps to reduce food wastage by extending the shelf life of fruits.

Explanation:

• Location of control: The involuntary actions in the body are primarily controlled by the medulla in the hindbrain.


• Functions of the medulla: The medulla is responsible for controlling vital functions such as breathing, heart rate, and blood pressure.


• Connection to the spinal cord: The medulla connects the brain to the spinal cord and serves as a pathway for signals between the brain and the rest of the body.


• Autonomic nervous system: The medulla plays a key role in regulating the autonomic nervous system, which controls involuntary actions in the body.


• Overall importance: The medulla is essential for maintaining homeostasis and ensuring the body functions properly without conscious effort.

The information coded in DNA (genes) is for only polypeptides (proteins). Insulin hormone is peptide and all enzyme are also proteins.

Explanation:

• X and Y Chromosomes: The maleness of a child is determined by the presence of a Y chromosome in the zygote. The sperm carries either an X or a Y chromosome, while the egg always carries an X chromosome. If the sperm carrying a Y chromosome fertilizes the egg, the resulting zygote will have XY chromosomes, making the child male. If the sperm carrying an X chromosome fertilizes the egg, the resulting zygote will have XX chromosomes, making the child female.


• Cytoplasm of Germ Cell: While the presence of the Y chromosome is the primary determinant of maleness, it is important to note that other factors in the cytoplasm of the germ cell can also influence the sex of the child. However, these factors play a secondary role compared to the presence or absence of the Y chromosome.


• Sex Determination: The sex of a child is not determined by chance. It is a result of the specific combination of chromosomes present in the zygote at the time of fertilization. While there is an element of randomness in the process of fertilization, the presence of the Y chromosome in the zygote is what ultimately determines maleness.

The given information states that different animals excrete different nitrogenous wastes. Let's analyze the options and determine the correct answer.
A: There is no uniform pattern of removal of nitrogen wastes.
This option is not correct because there is a pattern observed in the excretion of nitrogenous wastes among different animals.
B: Aquatic and land animals excrete urea.
This option is not correct because although some land animals excrete urea, not all aquatic animals excrete urea. For example, birds and insects excrete uric acid, which is not urea.
C: Animals that fly excrete uric acid.
This option is not correct because although birds, which are animals that fly, excrete uric acid, not all animals that fly excrete uric acid. For example, lizards and snakes also excrete uric acid, but they do not fly.
D: Nitrogen waste excretion is closely related to the availability of water in the environment.
This option is correct because the given information mentions that animals like crocodiles and alligators, which excrete ammonia, are aquatic animals. Ammonia is highly toxic and requires a lot of water for dilution and excretion. Therefore, the excretion of nitrogenous waste is closely related to the availability of water in the environment.
Hence, the correct answer is option D: Nitrogen waste excretion is closely related to the availability of water in the environment.

The white matter in a bird's dropping is uric acid. Here's a detailed explanation:
Definition of Bird Dropping:
Bird droppings, also known as bird poop or bird guano, are the excrement or feces of birds. They consist of various components, including uric acid.
Composition of Bird Droppings:
Bird droppings are composed of three main components:
1. Feces: The solid waste material produced by the bird's digestive system.
2. Uric Acid: A white, paste-like substance that is the waste product of protein metabolism in birds. It is insoluble in water, which allows birds to conserve water by excreting it in a concentrated form.
3. Urates: These are salts of uric acid and are also present in bird droppings.
Identification of the White Matter:
The white matter in a bird's dropping refers to the uric acid component. It is the main reason for the characteristic white color of bird droppings. The uric acid is excreted by the bird's kidneys and mixed with other waste materials before being expelled from the body.
Functions of Uric Acid:
Uric acid serves several functions in birds:
- It helps birds conserve water by excreting nitrogenous waste in a highly concentrated form.
- It plays a role in maintaining the bird's acid-base balance.
- It helps to regulate the bird's body temperature by reducing water loss through evaporation.
Therefore, the white matter in a bird's dropping is uric acid, which is responsible for the white color and characteristic appearance of bird droppings.

Where does fertilisation take place?

• Uterus: Fertilisation does not occur in the uterus. The uterus is where a fertilised egg implants and grows into a fetus during pregnancy.


• Vagina: Fertilisation does not occur in the vagina. The vagina is the passage that leads to the cervix.


• Fallopian tube: Fertilisation takes place in the fallopian tube. After ovulation, the egg travels through the fallopian tube where it can be fertilised by sperm if present.


• Cervix: Fertilisation does not occur in the cervix. The cervix is the lower part of the uterus that connects to the vagina.

Therefore, the correct answer is C: Fallopian tube.

Reduction division occurs during meiosis. Budding is seen in yeast and hydra while amoeba reproduces asexually by binary fission.

Menarche

• Definition: Menarche is the first occurrence of menstruation in a woman's life, signaling the beginning of her reproductive years.


• Age: Menarche typically occurs between the ages of 11 and 14, although it can vary widely among individuals.


• Significance: Menarche marks the onset of ovulation and the potential for pregnancy, as the woman's body is now capable of releasing eggs for fertilization.


• Hormonal Changes: Menarche is triggered by hormonal changes in the body, specifically an increase in estrogen levels that initiate the menstrual cycle.


• Physical Changes: Menarche is often accompanied by other physical changes such as breast development and body hair growth, indicating the transition to adulthood.


• Reproductive Health: It is important for women to understand the significance of menarche in relation to their reproductive health and to seek appropriate medical care and guidance as they navigate their reproductive years.

The correct answer is option C: Dichloro diphenyl trichloroethane.
Here is a detailed explanation of the answer:
1. Understanding the question:
The question asks about the pesticide DDT and its chemical name.
2. Analyzing the options:
Let's analyze each option to determine the correct answer:
- Option A: Diphenyl dichlero trichleroethyne
- Option B: Dichlero diphenyl trichleroethyne
- Option C: Dichloro diphenyl trichloroethane
- Option D: Diphenyl dichlero trichleroethane
3. Identifying the correct option:
To determine the correct option, we need to know the chemical formula and name of DDT.
4. DDT's chemical formula and name:
DDT stands for Dichloro diphenyl trichloroethane.
- "Di" indicates the presence of two chlorine atoms.
- "Chloro" indicates a chlorine atom.
- "Diphenyl" refers to two benzene rings connected together.
- "Trichloroethane" indicates the presence of three chlorine atoms in an ethane molecule.
5. Comparing the options:
Now, let's compare the chemical name of DDT with each option:
- Option A: Diphenyl dichlero trichleroethyne - This option is incorrect because it does not match the correct chemical name of DDT.
- Option B: Dichlero diphenyl trichleroethyne - This option is incorrect because it does not match the correct chemical name of DDT.
- Option C: Dichloro diphenyl trichloroethane - This option is correct as it matches the correct chemical name of DDT.
- Option D: Diphenyl dichlero trichleroethane - This option is incorrect because it does not match the correct chemical name of DDT.
6. Conclusion:
Based on the analysis, we can conclude that the correct answer is option C: Dichloro diphenyl trichloroethane.

Greenhouse gases are:
- Gases used in house for cooking: This option is incorrect as greenhouse gases are not related to gases used for cooking in houses.
- Green in colour: This option is incorrect as the term "greenhouse" in greenhouse gases does not refer to the color, but rather to the concept of trapping heat.
- Traps solar radiations and increase temperature: This option is correct. Greenhouse gases are gases that absorb and emit infrared radiation within the thermal infrared range. They trap solar radiation in the Earth's atmosphere, which leads to an increase in temperature, known as the greenhouse effect.
- None of these: This option is incorrect as option C is the correct answer.
In summary, greenhouse gases are gases that trap solar radiation and increase the temperature of the Earth's atmosphere. They are not related to gases used for cooking in houses or their color.

Insects and some other invertebrates exchange oxygen and carbon dioxide between their tissues and the air by a system of air-filled tubes called tracheae. Tracheae open to the outside through small holes called spiracles. Spiracles open into large tracheal tubes. These, in turn, lead to ever-finer branches. The branches penetrate to every part of the body. At their extreme ends, called tracheoles, they may be less than 1 m in diameter and are probably filled with liquid. Every cell in the insect's body is adjacent to, or very close to, the end of a tracheole.

Bronchiole is a fine respiratory tube in the lungs of reptiles, birds and mammals. It is formed by the subdivision of a bronchus. 

A child respires around 26 times per minute. Norman man respires 14-18 times per minute. If the CO₂ concentration in blood increases, the rate of breathing also increases. When CO₂ is dissolved in the blood, then blood becomes slightly acidic. The brain picks up the change and adjusts the breathing to get rid of CO₂ from the blood. Thus, option B is correct.

Archaeopteryx is an iconic fossil, often thought of as the 'missing-link' between dinosaurs and birds. It was first described in 1861 by the German palaeontology Hermann von Meyer (1801-1869). Since then Archaeopteryx has been the focus of controversy surrounding the origin of birds and their links with dinosaurs.

When the electrical impulse reaches the axon ending at synapse chemicals are released which on reaching the dendrite of next neuron again give rise to electrical impulse.

Which endocrine gland is also known as 'master gland'?

• Pancreas: The pancreas is responsible for producing insulin and glucagon to regulate blood sugar levels, but it is not known as the 'master gland'.



• Adrenal: The adrenal glands produce hormones like adrenaline and cortisol, but they are not referred to as the 'master gland'.



• Pituitary: The pituitary gland is often called the 'master gland' because it controls the functions of many other endocrine glands in the body. It secretes hormones that regulate growth, metabolism, and reproduction.



• Hypothalamus: The hypothalamus plays a key role in regulating the pituitary gland, but it is not typically referred to as the 'master gland' itself.

Therefore, the correct answer is Pituitary gland when it comes to being known as the 'master gland' due to its control over various other endocrine glands in the body.

Cerebellum is responsible for maintenance of body balance and posture.

Events if the ova does not fertilize:

• Menstruation: If the egg is not fertilized, the thickened lining of the uterus breaks down and sheds, resulting in menstruation.

Menstruation is a part of the menstrual cycle in which the endometrium (lining of the uterus) is shed, leading to the expulsion of blood and tissue from the vagina. This process allows the uterus to prepare for a potential pregnancy in the next cycle. If fertilization does not occur, the uterus eliminates the unneeded tissue and prepares for a new cycle.

Pollen tube passes from surface of stigma to the lowest part of pistil the ovary where ovules are located.

Reasons for Dialysis:

• Both kidneys are damaged: Dialysis is carried out when both kidneys are damaged and unable to perform their function of filtering waste and excess fluids from the blood.

When both kidneys are not functioning properly, waste products, toxins, and excess fluids can build up in the body, leading to serious health complications. Dialysis helps to artificially perform the function of the kidneys by removing these waste products and excess fluids from the blood.

Amoeba has a contractile vacuole as an excretory organ that gathers the excretory wastes delivered inside the cell.These waste materials are discharged out by the procedure of dispersion through the general body surface. In the single adaptable cell, contractile vacuoles additionally assume some part in the expulsion of waste materials.

Plant gets rid of excess water by transpiration.

• Definition: Transpiration is the process by which plants release water vapor through their leaves.


• Function: It helps in the regulation of water content and temperature in plants.


• Process: Transpiration occurs through small openings on the surface of leaves called stomata. These stomata open and close to control the release of water vapor.


• Factors affecting transpiration:
  
  
  
  • Temperature: Higher temperatures increase the rate of transpiration.
  
  
  • Humidity: Lower humidity levels promote faster transpiration.
  
  
  • Wind: Increased air movement increases the rate of transpiration.
  
  
  • Light: Intense light stimulates stomatal opening and increases transpiration.
  
  
  
  


• Importance:
  
  
  
  • Water transport: Transpiration helps in the upward movement of water from the roots to the leaves.
  
  
  • Nutrient absorption: It facilitates the absorption of minerals and nutrients from the soil.
  
  
  • Cooling effect: Transpiration cools down the plant and prevents overheating.
  
  
  • Turgor pressure: It maintains turgor pressure in plant cells, which is essential for support and structure.
  
  
  
  


• Difference from respiration and photosynthesis:
  
  
  
  • Respiration: Respiration is the process by which plants and animals convert glucose into energy. It occurs in all living cells.
  
  
  • Photosynthesis: Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose and oxygen. It occurs in the chloroplasts of plant cells.
  
  
  
  

Therefore, the correct answer is C: Transpiration.

Binary fission is a kind of asexual reproduction. In binary fission, the fully grown parent cell splits into two halves, producing two pools.

Since the reproduction is asexual, the newly created organism is a clone and is genetically identical to the parent organism. Organisms such as hydrause regenerative cells for reproduction in the process of budding. In hydra, a bud develops as an outgrowth due to repeated cell division at one specific site.

Amoeba reproduces by binary fission in any plane.

The fertilization of the human egg by the sperm takes place in the oviduct, specifically in the ampulla region of the fallopian tube.

Explanation:
To determine the correct evolutionary chain involving animals A, B, and C, we need to analyze the information provided in the passage.
1. Animal A can fly, while animal B can only run on ground or walls. This suggests that animal A developed the ability to fly, while animal B did not.
2. The forelimbs of animal A and B have the same basic design but are used for different purposes. This indicates that the forelimbs evolved differently in animal A and B to serve their respective functions.
3. Animal C, which is extinct, has features similar to both animal A and B. This suggests that animal C shares common ancestry with both animals A and B and can be considered a connecting link in their evolutionary chain.
Based on this information, the correct evolutionary chain involving animals A, B, and C is:
B: B → C → A
Animal B is the ancestor of animal C, and animal C is the ancestor of animal A. This chain implies that animal B, which can only run on ground or walls, evolved into animal C, which had features similar to both animal A and B. Animal C then further evolved into animal A, which developed the ability to fly.
Therefore, the correct answer is B: B → C → A.

Hormones synthesized at places away from where they act. Growth is seedling germination. Chemotropic is the growth of pollen tubes towards ovules. Root is positively geotrophic. Shoot is positively phototropic.

Auxin, cytokinin and gibberellins are growth promoting plant hormones while Abscisic acid is the growth inhibitior plant hormone.