Ch 6: Control and Coordination (NCERT Solutions)

NCERT Solutions for Class 10 Science Ch 6: Control and Coordination, is given below.

You will get solutions for;

• In-text questions as well as,
• Exercises questions.

So let’s dive into it!

In-text Questions Set-1

1) What is the difference between a reflex action and walking?

Solution:
Reflex actions are involuntary responses to stimuli that happen without involving the conscious parts of the brain. These actions are automatic and involve the brain and spinal cord of the central nervous system.

In contrast, voluntary actions are controlled by the cerebellum in the brain. For example, walking is a learned behavior that we consciously control whenever needed.

2) What happens at the synapse between two neurons?

Solution:
At the synapse between two neurons, electrical signals are converted into chemicals that cross the gap. These chemicals then pass the message to the next neuron, where it is converted back into an electrical signal.

3) Which part of the brain maintains the posture and equilibrium of the body?

Solution:
The cerebellum, a part of the brain, controls motor functions. It helps maintain the body’s posture and balance.

4) How do we detect the smell of an agarbatti (incense stick)?

Solution:
The nose detects the smell of an agarbatti (incense stick). The olfactory receptors in the nose send electrical signals to the forebrain, which then interprets these signals as the smell of the incense stick.

5) What is the role of the brain in reflex action?

Solution:
Reflex actions happen instantly in response to a stimulus, without time to think. For example, when sensory nerves detect heat, they quickly signal the nerves that move your hand away.

This quick connection between sensing a stimulus (input) and responding to it (output) is called a reflex arc.

Reflex actions are generated in the spinal cord, but the information also reaches the brain. This allows the brain to remember the event and help you be aware of similar dangers in the future.

In-text Questions Set-2

1) What are plant hormones?

Solution:
Plant hormones are natural substances made in specific parts of a plant and moved to other areas as needed. They help coordinate growth, development, and the plant’s response to the environment. Examples include auxins, gibberellins, cytokinins, abscisic acid, and ethylene.

3) Give an example of a plant hormone that promotes growth.

Solution:
Auxins and gibberellins are hormones that promote plant growth. Auxins help with cell elongation in the shoot and regulate overall growth. Gibberellins are responsible for stem elongation and seed germination.

4) How do auxins promote the growth of a tendril around a support?

Solution:
Auxins are plant hormones produced at the tips of shoots and roots. In tendrils, auxins are concentrated at the tips. When a tendril touches a support, the auxins move away from the contact point because they are sensitive to touch. This causes the side opposite the contact to grow faster, making the tendril bend towards the support.

In-text Questions Set-3

1) How does chemical coordination take place in animals?

Solution:
Chemical coordination in animals occurs through hormones, which are chemical messengers secreted by specific endocrine glands. These hormones regulate growth, development, and the body’s internal balance.

2) Why is the use of iodized salt advisable?

Solution:
Using iodized salt is recommended to prevent iodine deficiency. Without enough iodine, the thyroid gland produces less thyroxine, which can disrupt the metabolism of fats, carbohydrates, and proteins. This can lead to goiter, a condition caused by low iodine intake.

3) How does our body respond when adrenaline is secreted into the blood?

Solution:
Adrenaline is a hormone released when we are scared or stressed. It makes the heart beat faster to pump more blood to our muscles and increases our breathing rate by causing the diaphragm and rib muscles to contract.

Adrenaline also raises blood pressure and boosts glucose levels in the blood. These changes help the body react quickly to stress.

4) Why are some patients of diabetes treated by giving injections of insulin?

Solution:
Diabetes occurs when the pancreas stops producing enough insulin, a hormone that helps control blood glucose levels by turning excess glucose into glycogen.

Without enough insulin, blood glucose levels rise, leading to various health problems. To manage this, people with diabetes receive insulin injections to help regulate their glucose levels.

Exercise Questions

1) Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin

Solution:
(d) Cytokinin

2) The gap between two neurons is called a
(a) Dendrite.
(b) Synapse.
(c) Axon.
(d) Impulse.

Solution:
(b) Synapse

3) The brain is responsible for
(a) Thinking.
(b) Regulating the heartbeat.
(c) Balancing the body.
(d) all of the above.

Solution:
(d) 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?

Solution:
Receptors are found all over our body, especially in our sense organs. They gather information about changes around us and send signals to the brain, which then responds. If receptors don’t work correctly, they can’t send the necessary signals, and the body doesn’t respond to changes.

6) How does phototropism occur in plants?

Solution:
The movement and growth of plants toward light is called phototropism. It happens because there’s more auxin (a growth hormone) on the darker side of the plant and less on the side exposed to light. The extra auxin makes the dark side grow faster, causing the plant to bend toward the light.

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

Solution:
In a spinal cord injury, signals from the nerves and signals to the receptors are both disrupted because they all travel through the spinal cord.

8) How does chemical coordination occur in plants?

Solution:
Plant growth, development, and responses to the environment are controlled by special chemicals called hormones. These hormones are made in one part of the plant and travel to other parts where they are needed.

The five main types of plant hormones are auxins, gibberellins, cytokinins, abscisic acid, and ethylene. Auxins, gibberellins, cytokinins, and ethylene act as growth promoters, while abscisic acid serves as a growth inhibitor.

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

Solution:
Organisms have various organs that must be carefully controlled and coordinated for survival. In the body, glands of the endocrine system secrete hormones that regulate growth and development. The central nervous system (CNS) manages both voluntary and involuntary actions.

Coordination is essential for all human activities. Our nervous system processes information from our surroundings and triggers responses. The endocrine system integrates metabolic activities such as reproduction and development.

In plants, the hormonal system supports processes like photosynthesis. For example, stomata open to allow carbon dioxide, roots grow toward water, stems grow toward sunlight, and tendrils help climbing plants. Overall, a control and coordination system is crucial for the functioning of both animals and plants.