Sunday, June 19, 2022

Class 10 Science | Chapter-end Exercise & Answers | Chapter 7 | Control and Coordination

1.   Which of the following is a plant hormone?

(a) Insulin                  

(b) Thyroxin

(c) Oestrogen            

(d) Cytokinin


(d) Cytokinin

2.   The gap between two neurons is called a

(a) dendrite               

(b) synapse

(c) axon                      

(d) impulse


(b) Synapse

3.   The brain is responsible for

(a) thinking                

(b) regulating the heartbeat

(c) balancing the body           

(d) all of the above


(b) All of the above

4.   What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise? 


The function of receptors is to detect information from the environment. E.g., photoreceptors in eye detect light.

If receptors do not work properly, the information obtained from the environment will not reach the CNS. As a result, the body cannot respond to the environmental stimuli. It affects our abilities such as vision, hearing, smell, taste, touch etc.

5.   Draw the structure of a neuron and explain its function.


Function: Neurons carry information (electrical signals called impulses) to and from the CNS.

6.   How does phototropism occur in plants?

Phototropism is the movement of a plant part due to light. The shoot shows positive phototropism and roots show negative phototropism.

Phototropism occurs due to the hormone auxin. When light falls on one side of a plant, the secretion of auxin hormone is more in the part away from the light. Hence, auxin causes growth in length of the cells in shady part. So, the plant bends towards light.

7.   Which signals will get disrupted in case of a spinal cord injury?


·    All the involuntary actions will be disrupted.

·    Reflex actions will be disrupted.

·    Signals to and from the brain will be disrupted.

8.   How does chemical coordination occur in plants?


Chemical coordination in plants occurs with the help of plant hormones. In meristematic regions, cells secrete hormones such as auxins. These substances identify the information by stimulating the nearby cells and communicate the information.

9.   What is the need for a system of control and coordination in an organism?


·    To save the body of the organisms from the harmful changes in the environment.

·    To respond to external and internal stimuli.

·    To control voluntary and involuntary actions.

10. How are involuntary actions and reflex actions different from each other?


Involuntary action: It is a set of muscle movements that do not require thinking. It is controlled by the brain. E.g., heartbeat.

Reflex action: It is a rapid and spontaneous response to a stimulus. It is controlled by spinal cord. E.g., sudden withdrawal of hand when we touch a hot object.

11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.


Nervous Mechanism

Hormonal Mechanism

It involves neurons (nerve cells).

It involves endocrine glands.

Signals are transferred in the form of electrical impulses.

Signals are transferred in the form of chemicals (hormones).

Impulses travel quickly.

Hormones travel slowly.

Quick response.

Slow response.

Signals travel along the neurons.

Signals are transmitted through blood.

The effects are short-lived.

The effects are prolonged.

12. What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?


Movement in a sensitive plant

Movement in our legs

Leaves respond to touch (nastic movement).

Leg muscles respond to nerve impulses.

It is not controlled by any part of the plant.

It is controlled by brain and spinal cord.

Here, cells change their shape on changing the amount of water in them.

Water has no effect on the muscle movement.

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