Class 10th Science Chapter 6 – Control and Coordination – Exercises

Q1. Which of the following is a plant hormone?

(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin

Answer: (d) Cytokinin

Explanation:

• Insulin, thyroxin and oestrogen are human hormones.

• Cytokinin is a plant hormone that promotes cell division and growth.

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Q2. The gap between two neurons is called a

(a) dendrite
(b) synapse
(c) axon
(d) impulse

Answer: (b) synapse

Explanation:

A synapse is a microscopic gap between two neurons through which nerve impulses pass using chemical neurotransmitters.

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Q3. The brain is responsible for

(a) thinking
(b) regulating the heartbeat
(c) balancing the body
(d) all of the above

Answer: (d) all of the above

Explanation:

• Thinking is controlled by cerebrum

• Heartbeat is regulated by medulla

• Balance and posture are controlled by cerebellum
  Therefore, the brain performs all of these functions.

Q4. What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?

Answer:

Receptors are special cells present in our sense organs that receive stimuli such as light, sound, smell, taste, pressure, pain, and temperature.
They send this information to the brain through nerve impulses for interpretation and response.

If receptors do not work properly:

• We may not feel pain or danger signals (e.g., touching a hot object)

• We may lose senses such as hearing, vision, smell, taste, or touch

• The body may fail to respond correctly to the environment, causing accidents or injuries

Example:

A person whose pain receptors are damaged may touch fire without realising and get burnt.

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Q5. Draw the structure of a neuron and explain its function.

Answer:

Diagram of a Neuron (rough sketch format for exam)

Function:

A neuron is the structural and functional unit of the nervous system.
Its function is to receive and transmit nerve impulses from one part of the body to another.

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Q6. How does phototropism occur in plants?

Answer:

Phototropism is the growth movement of plants in response to light.

How it occurs:

• When light falls on one side of the plant shoot, the auxin hormone moves to the shaded side.

• Cells on the shaded side elongate more than cells on the lighted side.

• This causes the shoot to bend towards the light.

Example:

Bending of a plant stem towards sunlight.

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Q7. Which signals will get disrupted in case of a spinal cord injury?

Answer:

If the spinal cord is damaged, the following signals will be disrupted:

• Reflex actions

• Communication between brain and body

• Movement and muscle control

• Sensory signals from body parts

• Control of organs below the injury

Result:

Paralysis, loss of sensation, and inability to coordinate body movements.

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Q8. How does chemical coordination occur in plants?

Answer:

Chemical coordination in plants occurs through plant hormones.
These hormones are produced in one part of the plant and transported to other parts where they regulate growth and responses.

Important plant hormones:

Q9. What is the need for a system of control and coordination in an organism?

Answer:

An organism needs a system of control and coordination to:

• Receive information from the surroundings

• Process and respond to stimuli correctly

• Coordinate functions of different organs

• Maintain balance and homeostasis

• Ensure survival in changing environments

Explanation:

Control and coordination help different body parts work together smoothly, for example:

• Running away from danger

• Adjusting body temperature

• Regulating heartbeat and breathing

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Q10. How are involuntary actions and reflex actions different from each other?

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Q11. Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

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Q12. What is the difference between the manner in which movement takes place in a sensitive plant and movement in our legs?