MODEL PAPER – III (E/M)
GENERAL SCIENCE – II (Biological Science)
CLASS: X
PART: A & B
MAX. MARKS: 40
TIME: 1.35 Hours
PART A (30 MARKS)
SECTION – I (3 x 2 = 6 MARKS)
1. What is Photosynthesis? Mention the equation.
Answer:
Photosynthesis is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll. The process occurs mainly in the chloroplasts of plant cells.
Photosynthesis equation:6CO2+6H2O+light energy→C6H12O6+6O26CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_26CO2+6H2O+light energy→C6H12O6+6O2
This shows that carbon dioxide and water are converted into glucose and oxygen using light energy.
2. On whom does sexual determination in humans depend? Why?
Answer:
Sexual determination in humans depends on the sex chromosomes inherited from the parents.
- Females have two X chromosomes (XX), and males have one X and one Y chromosome (XY).
- The sex of the offspring is determined by the sperm from the male, which can carry either an X or a Y chromosome.
- If the sperm carries an X chromosome, the offspring will be female (XX), and if the sperm carries a Y chromosome, the offspring will be male (XY).
3. What is Tissue culture? Write its uses.
Answer:
Tissue culture is a technique in which cells or tissues from a plant or animal are cultured in a nutrient-rich medium under controlled conditions.
Uses of Tissue Culture:
- Plant breeding: Used to grow new plants from a small piece of plant tissue.
- Genetic modification: Helps in the production of genetically modified plants.
- Conservation of endangered species: Helps in the conservation of rare plant species.
- Medical applications: In growing tissues for medical purposes such as skin grafts or growing organs for transplantation.
SECTION – II (3 x 4 = 12 MARKS)
4. Pain in muscles during exercise. What is the relation between muscle pain and breathing?
Answer:
When muscles undergo strenuous exercise, they may experience pain due to the buildup of lactic acid. This happens because, during intense physical activity, muscles do not get enough oxygen to perform aerobic respiration. Instead, they perform anaerobic respiration, which produces lactic acid as a byproduct.
Relation to breathing:
The pain in muscles is connected to the lack of oxygen during exercise. Heavy breathing helps to supply more oxygen to the muscles, allowing them to clear the lactic acid buildup and return to normal functioning.
5. Name the various hormones present in plants and write their uses.
Answer:
The major plant hormones are:
- Auxins: Promote cell elongation, root development, and fruit development.
- Cytokinins: Promote cell division and shoot formation.
- Gibberellins: Stimulate growth, seed germination, and flowering.
- Ethylene: A gas that promotes fruit ripening and flower wilting.
- Abscisic acid: Inhibits growth and helps in seed dormancy.
Uses: These hormones are used in agriculture to control growth patterns, enhance fruit production, and improve crop yield.
6. Analyze the table and answer the questions given below.
| Sl. No. | Hormone name | Name of the Endocrine glands | Its duties |
|---|---|---|---|
| 1. | Somatotropin | Pituitary gland | Bone growth |
| 2. | Vasopressin | Pituitary gland | Regulates water absorption in kidney vessels |
| 3. | Thyroxin | Thyroid | Growth, Metabolic rate |
| 4. | Insulin | Pancreas | Reduces the glucose level in blood |
| 5. | Glucagon | Pancreas | Increases the glucose level in blood |
Q1. What is the hormone secreted by the Langerhans islets?
Answer:
The hormone secreted by the Langerhans islets in the pancreas is insulin and glucagon. Insulin reduces blood glucose levels, while glucagon increases it.
Q2. What are the functions of the thyroxin hormone?
Answer:
Thyroxin, secreted by the thyroid gland, is responsible for regulating metabolism in the body. It helps in the growth and development of the body and maintains the metabolic rate.
Q3. What happens if somatotropin is not secreted?
Answer:
If somatotropin (growth hormone) is not secreted, it can lead to dwarfism in children, characterized by stunted growth and underdevelopment of the bones.
Q4. What is the main function of hormones?
Answer:
The main function of hormones is to regulate various physiological processes in the body. They act as chemical messengers that influence growth, metabolism, immune function, reproduction, and other vital processes.
SECTION – III (2 x 6 = 12 MARKS)
7. What kind of experiment would you do to say that a green plant releases oxygen when exposed to sunlight?
Answer:
An experiment to demonstrate that plants release oxygen during photosynthesis is the “Elodea in water” experiment.
Procedure:
- Take a test tube with water and place a piece of green plant (e.g., Elodea) inside.
- Place the test tube under sunlight.
- After some time, oxygen bubbles will start to form on the plant’s surface, indicating oxygen production.
- Collect the gas in an inverted test tube or container.
- The presence of oxygen can be confirmed by using a glowing splint, which will reignite when exposed to the gas.
8. Draw the picture of Dhatura flower, identify the parts, and briefly explain each part.
Answer:
(Drawing not available in text form, but here is the explanation)
The Dhatura flower (also known as Datura) is a large, funnel-shaped flower with trumpet-like petals. The parts of the flower are:
- Sepals: Protect the developing flower bud.
- Petals: The colorful part that attracts pollinators.
- Stigma: The female reproductive part that receives pollen.
- Anthers: Male reproductive part that produces pollen.
- Filament: Stalk supporting the anther.
- Ovary: The base of the pistil, containing ovules that will develop into seeds.
9. Write about the basic principles (4R) required for environmental protection.
Answer:
The basic principles for environmental protection are known as the 4Rs:
- Reduce: Minimize waste generation by consuming fewer resources.
- Reuse: Use products and materials more than once instead of discarding them.
- Recycle: Process waste materials to create new products and reduce the need for raw materials.
- Recover: Retrieve useful materials from waste, such as energy recovery from waste products.
PART B (10 x 1 = 10 MARKS)
Choose the correct answer and explain.
1. Which hormone is released when appetite is suppressed?
- A. Leptin
- B. Greelin
- C. Tyalin
- D. Which is not
Answer: A. Leptin
Leptin is the hormone that helps regulate appetite. It is secreted by fat cells and signals the brain to reduce hunger when the body has enough energy stored.
2. The hormone that stimulates the ripening of fruits.
- A. Auxins
- B. Cytokinins
- C. Ethylene
- D. Gibberellin
Answer: C. Ethylene
Ethylene is a gas that acts as a plant hormone to regulate the ripening of fruits. It accelerates the ripening process, making fruits ready for harvest.
3. Acid released in the digestive system.
- A. NaOH
- B. HCl
- C. HNO3
- D. H2SO4
Answer: B. HCl
Hydrochloric acid (HCl) is secreted in the stomach to help break down food and kill harmful microorganisms.
4. Example of open-type circulation system.
- A. Frog
- B. Man
- C. Earthworm
- D. Butterfly
Answer: C. Earthworm
An earthworm has an open circulatory system, where the blood flows freely in the body cavity without being confined to vessels.
5. What is the center point of mental abilities?
- A. Diencephalon
- B. Cerebrum
- C. Cerebellum
- D. Medulla oblongata
Answer: B. Cerebrum
The cerebrum is responsible for higher brain functions, including thinking, memory, and voluntary movements.
6. Which vitamin has been identified as essential for the body due to Corona conditions?
- A. A
- B. D
- C. B
- D. E
Answer: B. D
Vitamin D is essential for immune function and has been highlighted as important during the COVID-19 pandemic.
7. There is no excretory organ in the following.
- A. Birds
- B. Reptiles
- C. Amoeba
- D. A & B
Answer: C. Amoeba
Amoeba does not have a specialized excretory organ. It uses diffusion to remove waste products.
8. Identify the herbivores in the ecosystem.
- A. Producers
- B. Primary consumers
- C. Secondary consumers
- D. Tertiary consumers
Answer: B. Primary consumers
Herbivores are primary consumers that feed on producers (plants) in an ecosystem.
9. What is the Centre point of mental abilities?
- A. Diencephalon
- B. Cerebrum
- C. Cerebellum
- D. Medulla oblongata
Answer:
B. Cerebrum
Explanation:
The cerebrum is the largest part of the brain and is responsible for higher mental functions such as thinking, memory, decision-making, and voluntary movements. It is divided into two hemispheres and controls the intellectual, sensory, and motor functions. The cerebrum is the center of mental abilities like learning, thought processes, reasoning, and emotions.
- Diencephalon: Involved in sensory and motor signal relay and regulation of sleep.
- Cerebellum: Coordinates voluntary movements and balance.
- Medulla Oblongata: Controls involuntary functions like breathing, heartbeat, and blood circulation.
10. Which vitamin has been identified as essential for the body due to Corona conditions?
- A. Vitamin A
- B. Vitamin D
- C. Vitamin B
- D. Vitamin E
Answer:
B. Vitamin D
Explanation:
Vitamin D plays a significant role in maintaining the immune system and is important for overall health, especially during the COVID-19 pandemic. Research suggests that adequate levels of Vitamin D may help reduce the risk of respiratory infections and improve immune function. It helps the body absorb calcium and supports bone health, and there is evidence to suggest it may assist in fighting infections like COVID-19.
- Vitamin A: Important for vision and immune function.
- Vitamin B: Vital for energy production and the functioning of the nervous system.
- Vitamin E: Acts as an antioxidant and supports immune function.