Class 10 Science: Control and Coordination important questions

Control and Coordination is a chapter of Class 10 Science for the CBSE. These 10 questions are marked Very Important, Important or Practice, and each answer has been checked by our team. Use them to revise, not as a prediction of what will come in the exam.

1. Practice · 1 marks

   1. Receptors are usually located in sense organs. Gustatory receptors are present in a) tongue b) nose c) eye d) ear

   a) tongue

2. Practice · 1 marks

   2. Height of a plant is regulated by: a) DNA which is directly influenced by growth hormone. b) Genes which regulate the proteins directly. c) Growth hormones under the influence of the enzymes coded by a gene. d) Growth hormones directly under the influence a gene.

   c) Growth hormones under the influence of the enzymes coded by a gene.

3. Important · 3 marks

   3. We are advised to take iodised salt in our diet by doctors. Justify it's importance in our body.

   - Iodine is essential for the synthesis of thyroxin hormone. - Thyroxin regulates carbohydrate, protein and fat metabolism in the body. - Thyroxin provide best balance for growth in the body.

4. Practice · 1 marks

   4. There was a cerebellar dysfunction in a patient. Which of the following activities will get disturbed in this patient as a result of this? A. Salivation B. Hunger control C. Posture and balance D. Regulation of blood pressure

   C. Posture and balance.

5. Very Important · 4 marks

   5. During a field trip, Mohan and Rohit observed that shoots of sunflower plants bend towards the sunlight. Whereas, leaves of ‘Touch me not’ plant begin to fold and droop soon after touching even during the day. They were curious to know how these movements occur in plants. A. What causes the bending of shoots in the sunflower plants towards sunlight? OR B. What causes the folding of the leaves in ‘Touch me not’ plants when touched by hand? C. Compare the movement of growth of the pollen tube towards ovule with the bending of shoots of sunflower plant towards sunlight. D. Compare the movement in folding of leaves of ‘Touch me not’ plants with the movement of body parts in the animals.

   A. ● Bending of shoots of plants is a response to the stimulus and a directional, growth-related movement. ● When growing plants detect sunlight, a hormone called auxin, synthesized at shoot tip helps the cells to grow longer. ● When light is coming from one side of the plant, auxin diffuses to the shady side of the shoot. ● This concentration of auxin stimulates the cells of the shoot to grow longer on the side of the shoot which is away from the light. Thus, plant appears to bend towards light. (0.5 x 4 =2) OR B. ● Leaves of ‘Touch me not’ plant respond to the stimulus by showing growth independent movement. ● These plants use electrical–chemical means to convey the information from cell to cell. ● Movement happens at a point different from the point of touch. ● Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking, and therefore in changing shape. (0.5 x 4 =2) C. Growth of pollen tubes towards the ovule is an example of chemotropism whereas bending of shoots towards sunlight is an example of phototropism. D. i) Although both plants and animals show electrical–chemical means to convey the information from cell to cell but unlike nerve cells in animals there is no specialized tissue in plants for conduction of information. ii) In animal cells, change in shape occurs because of the specialized proteins found in muscle cells; plant cells change shape by changing the amount of water in them.

6. Practice · 1 marks

   6. Which of the following is a correct combination of function and part of the brain? A. Posture and balance: Cerebrum B. Salivation: Medulla in midbrain C. Hunger: Pons in hindbrain D. Blood pressure: Medulla in hindbrain

   D. Blood pressure: Medulla in hindbrain

7. Practice · 1 marks

   7. The blood glucose level in a patient was very high. It may be due to inadequate secretion of: A. growth hormone from pituitary gland B. oestrogen from ovary C. insulin from pituitary gland D. insulin from pancreas

   D. insulin from pancreas

8. Important · 3 marks

   8. Draw and explain how the nerve cells help in transmission of impulses?

   - All information from our environment is detected by the specialised tips of some nerve cells. The information acquired at the end of the dendritic tip of a nerve cell (Fig. a), sets off a chemical reaction that creates an electrical impulse. - This impulse travels from the dendrite to the cell body, and then along the axon to its end. At the end of the axon, the electrical impulse sets off the release of some chemicals. - These chemicals cross the gap, or synapse, and start a similar electrical impulse in a dendrite of the next neuron. This is how nervous impulses travel in the body. (Fig b).

9. Important · 2 marks

   9. A. Which parts of the brain perform certain actions for which we do not have any thinking control? What are such actions called, give two examples. OR B. How is the information of touch in the ‘sensitive plant' controlled and coordinated?

   The actions on which we do not have any thinking control are controlled by the mid-brain and hind-brain. These are called involuntary actions. Examples (any two) blood pressure, salivation and vomiting OR The information of touch is communicated by electrical-chemical means from cell to cell. Plant cells change shape by changing the amount of water in them, resulting in swelling or shrinking, thus changing shapes and causing movement.

10. Important · 3 marks

    10. How do muscles move at the cellular level and respond when processed messages are received from the brain?

    - When a nerve impulse reaches the muscle, the muscle cells will move by changing their shape so that they shorten. - Muscle cells have special proteins that change both their shape and their arrangement in the cell in response to nervous electrical impulses. - When this happens, new arrangements of these proteins give the muscle cells a shorter form.