NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination

Control and Coordination Topic 7.1 Animals Nervous System:

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

Answer:

The difference between a reflex action and walking-

Q.2 . What happens at the synapse between two neurons ?

Answer:

The synapse is the small empty space between the two nerve cells. At the synapse, a chemical substance is produced at the end of the axon of one of the neurons that reaches to the other neurons with the help of dendrite. Therefore, the information signal is transmitted through one neuron to other neurons by synapse.

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

Answer:

Cerebellum control and maintains the posture and equilibrium of the body.

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

Answer:

The smell of agarbatti (incense stick) mixed in the air. It is detected by the olfactory receptor of the nose. The sensory nerves of the forebrain sent this information to the olfactory lobe and respond to the information signal.

Q.5. What is the role of the brain in reflex action ?

Answer:

There is no role of the brain in a reflex action. These involuntary actions are controlled by the spinal cord, which reacts immediately without thinking of how to respond to a stimulus.

Solutions of NCERT for class 10 science chapter 7 control and coordination topic 7.2 Coordination in plants:

Q.1. What are plant hormones ?

Answer:

Plant hormones - These are also called phytohormones. Plant hormones are the chemical substance which helps in the growth of the plant(height), flowering and also the development of plants and their response to the environment.
For example; auxins, gibberellins and cytokinins are some phytohormones.

Q.2. How is the movement of leaves of the sensitive plant different from the movement of a shoot towards light ?

Answer:

Here is the difference:

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

Answer:

Auxins is phytohormones that promote the growth in plants.

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

Answer:

When the tip of tendril touches support, then auxin of that side of the tip is moving away from the side of the support. As we know, auxin promotes growth. So, due to the presence of more auxin in it, the side of tendril away from the support grow longer and faster than the support side. And due to this type of growth, it makes the tendrils bend around the support.

Q.5. Design an experiment to demonstrate hydrotropism

Answer:

The movement of the plant in the direction of the stimulus is called tropism.

AIM: To demonstrate hydrotropism in plants.

PROCEDURE :

i. Plant a seedling in a vessel containing soil.

ii. Adjacent to the seedling put a porous pot containing water.

iii. Leave the set up for a few days.

OBSERVATION :

iv. On examining the roots of seedlings it is observed that the roots bend towards the source of water and do not grow straight.

RESULT :

It confirms that plant shows hydrotropism as the roots bend towards the porous pot of water. Hydrotropism is a plant growth response in which the direction of growth is determined by a stimulus of the gradient in water concentration.

Control and Coordination Class 10 Topic 7.3 Harmones in Animals:

Q.1 . How does chemical coordination take place in animals ?

Answer:

In animals, chemical coordination takes place through the hormones secreted by the endocrine gland. It can also be done by the nervous system, which is called the endocrine system. Endocrine glands secrete hormone directly into the bloodstream that directly reaches to the specific cells. These cells act accordingly to the information that particular hormones carry.

Q.2. Why is the use of iodised salt advisable ?

Answer:

Thyroid glands need iodine to produce the thyroxine hormone which, controls the metabolic activities in our body such as metabolism of carbohydrates, fats and protein etc. Aso, due to lack of thyroxin a disease called goitre is caused.

That's why it advised using iodised salts.

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

Answer:

The rate of heartbeat becomes faster when adrenaline is secreted into the blood so that the supply of oxygen to our muscles is more. The amount of blood to the digestive system and skin is reduced because of the small arteries around the muscles of these organs contract.

As a result, it turns the direction of blood towards our skeletal muscles. The respiration function becomes faster due to the contraction of diaphragm and rib muscles.

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

Answer:

Insulin hormone regulates the level of sugars in the blood. If it is not adequately secreted, then the sugar level rises in our blood, causing many harmful effects. So, that is why diabetic patients are treated by giving injections of insulin.