Question Bank — Control and Coordination

Section A — MCQs (10 questions, 1 mark each)

1. The gap between the axon terminal of one neuron and the dendrite of the next neuron is called:
   (a) receptor (b) synapse (c) impulse (d) hormone

2. Which part of the brain controls involuntary actions such as blood pressure and salivation?
   (a) Cerebrum (b) Cerebellum (c) Medulla (d) Fore-brain

3. In plants, the movement of leaves of the sensitive plant (Mimosa) in response to touch is:
   (a) growth-dependent and slow (b) growth-independent and rapid (c) caused by auxin (d) due to electrical impulses only

4. Iodine is required for the synthesis of which hormone?
   (a) Adrenaline (b) Thyroxin (c) Insulin (d) Growth hormone

5. Assertion (A): Reflex arcs are formed in the spinal cord.
   Reason (R): The brain is not fast enough to produce quick responses in dangerous situations.
   (a) Both A and R are true and R is the correct explanation of A.
   (b) Both A and R are true but R is not the correct explanation of A.
   (c) A is true but R is false.
   (d) A is false but R is true.

6. Assertion (A): Auxin helps the shoot to bend towards light.
   Reason (R): Auxin diffuses towards the shady side and stimulates cell elongation there.
   (a) Both A and R are true and R is the correct explanation of A.
   (b) Both A and R are true but R is not the correct explanation of A.
   (c) A is true but R is false.
   (d) A is false but R is true.

7. Which hormone prepares the body for fight-or-flight by increasing heart rate and breathing rate?
   (a) Thyroxin (b) Insulin (c) Adrenaline (d) Oestrogen

8. The part of the neuron that acquires information from the environment is the:
   (a) axon (b) dendrite (c) cell body (d) synapse

9. Cytokinins are plant hormones that:
   (a) inhibit growth (b) promote cell division (c) cause wilting of leaves (d) help in stem elongation only

10. Feedback mechanism in hormone action ensures that:
    (a) hormones are secreted continuously (b) the amount and timing of hormone release is regulated (c) only electrical impulses are used (d) growth occurs in one direction only

Section B — Very Short Answer (6 questions, 2 marks each)

1. Differentiate between gustatory and olfactory receptors with one example of each.
2. State the function of the cerebellum.
3. How do plant cells change shape to bring about movement in the sensitive plant?
4. Name the hormone secreted by the pancreas and state its role in the body.
5. What is the role of abscisic acid in plants?
6. Why is the brain protected inside a bony box filled with fluid?

Section C — Short Answer (5 questions, 3 marks each)

1. Describe the path of a nerve impulse from the dendritic tip to the axon terminal of a neuron.
2. Explain how the reflex arc allows a quicker response than a response involving the brain. Draw a simple flow diagram of the reflex arc.
3. How does auxin cause phototropic movement in plants? Explain with the help of an example.
4. List three differences between voluntary actions and reflex actions.
5. Why is iodised salt recommended in our diet? What happens in its absence?

Section D — Long Answer (3 questions, 5 marks each)

1. Draw a neat labelled diagram of a neuron. Describe the function of each part and explain how an electrical impulse is converted into a chemical signal at the synapse.
2. Describe the structure and functions of the three major parts of the human brain (fore-brain, mid-brain and hind-brain). Give one example of an action controlled by each part.
3. Explain the role of adrenaline in preparing the body to deal with a scary situation. How does this chemical coordination differ from nervous coordination in terms of speed and reach?

Section E — Case/Source-Based (2 questions, 4 marks each)

Case 1

Riya touches a hot pan accidentally. She immediately withdraws her hand before she feels the pain. Later she realises that the information also reached her brain.

(a) Name the type of action shown by Riya.
(b) Where is the connection between the sensory and motor neurons made in this action?
(c) Why does the brain receive the information even though the action is completed quickly?
(d) What would happen if this connection were made only in the brain instead of the spinal cord?

Case 2

A student keeps a potted plant inside a cardboard box with a small opening on one side facing a window. After a few days, the shoot bends towards the opening while the roots grow in the opposite direction.

(a) Name the type of movement shown by the shoot and the root.
(b) Which hormone is responsible for the bending of the shoot? Where is it synthesised?
(c) Explain why the shoot bends towards light while the root grows away from it.
(d) If the plant is rotated so that the shoot now faces away from light, what change will be observed in new growth after a few days?

Section F — HOTS and Application (4 questions, 3 marks each)

1. Predict-and-justify: What would happen if the secretion of growth hormone from the pituitary gland became very low during childhood? Justify your answer.
2. Analyse an anomalous observation: In an experiment, a plant kept in a dark room for three days is exposed to light from one side only. After two days the shoot bends towards light, but one leaf on the shady side shows no bending. Give a possible scientific reason based on the chapter.
3. Apply to an unfamiliar situation: A person suffering from diabetes is advised to take insulin injections. Explain how this treatment restores coordination in the body and why it must be given externally.
4. Compare two situations: In a touch-me-not plant, leaves fold rapidly on touching. In a pea plant, tendrils coil slowly around a support. Compare the two movements and justify why the mechanisms and speeds differ.