NCERT Solutions Class 10 for Science Chapter 7 Control and Co-Ordination

NCERT Solutions Class 10 for Science Chapter 7 Control and Co-Ordination : In this post, we will share with you all the detailed NCERT Solutions of Class 10 Science Chapter 7 Control and Co-Ordination. This will contain both in-text and back-exercise questions for Science and Social Science, and all exercise questions for Mathematics. For all school and board level examinations, doing all the NCERT Questions is a must.

Why are NCERT Questions Important?

NCERT Questions and Answers not only help you get hold of concepts firmly and enhance your understanding, but also form the base of all types of questions asked in exams. Questions asked in exam are more or less the same type as mentioned in NCERT. Moreover, sometimes the questions in NCERT are directly asked in exams, as it is, without any changes.

Hence, it’s very important to understand NCERT Questions and Answers.

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Class 10 Science Chapter 7 Control and Co-Ordination

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In-Text Questions (Page 119)

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

Answer 1:
Reflex action are the involuntary actions that occur in response to stimuli. They occur without involvement of conscious areas of brain. All the reflex actions are unconscious actions. Reflex action occurs brain and spinal cord of central nervous systems.
On the other hand voluntary actions are those which occur under the control of cerebellum of the brain Walking is learnt as we grow. Walking is controlled by brain as is used when required.

Question 2:
What happens at the synapse between two neurons?

Answer 2:
Between the synapse between two neurons electric signals are converted into chemicals that can easily cross over the gap and pass on the chemical messenger to next neuron where it is converted back to electrical signal.

Question 3:
Which part of the brain maintains posture and equilibrium of the body

Answer 3:
Posture and equilibrium of the body are controlled by cerebellum

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

Answer 4:
The smell of agarbatti (incense stick) diffuses in the air. It is detected by olfactory receptors present in the nose. This information is sent to olfactory lobe by sensory nerves located in the forebrain. It responds to the information.

Question 5:
What is the role of the brain in reflex action ?

Answer 5:
Reflex actions are formed instantaneously in response to the stimulus that has no time to think. For instance the sensory nerves that detect the heat are connected to the nerves that move the muscles of the hand. Such a connection of detecting the signal from the nerves (input) and responding to it quickly (output) is known as reflex arc.
Reflex action are generated in spinal cord and the information also reaches brain. This helps the brain to record this event and remember it for future use. Brain helps the person to get awareness of the stimulus and prevent himself from that situation again.

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In-Text Questions (Page 122)

Question 1:
What are plant hormones ?

Answer 1:
Plant hormones are also called phytohormones. Plant hormones are the chemical substances which help in controlling growth, flowering, height, development of plants and their response to the environment.
Different types of phytohormones are – auxins, gibberllins, cytokinins, abscisic acid and ethylene.

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

Answer 2:

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

Answer 3:
Auxins and Gibberlins are the hormone responsible for the growth of plant.
Auxins are responsible for the cell elongation in shoot and also regulates growth.
Gibberlin is responsible for stem elongation and germination.

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

Answer 4:
Auxins are the plant hormones produces at the tip of a shoot and root. Auxins are present at the tip of tendrils. When tendrils are attached around any support their growth is slowed down as auxins are sensitive to touch. This make them move to the other side of the tip to get support this makes the other side grow faster than the side of tendril in contact with the support and the tendril bends towards the support.

Question 5:
Design an experiment to demonstrate hydrotropism

Answer 5:
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 few days.

Observation :
iv. On examining the roots 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. As hydrotropism is a plant growth response in which the direction of growth is determined by a stimulus of gradient in water concentration.

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In-Text Questions (Page 125)

Question 1:
How does chemical coordination take place in animals?

Answer 1:
Chemical coordination in animals takes place through the hormones secreted by the endocrine glands. Coordination in animals takes place through hormone system as well as nervous system which is called endocrine system. Endocrine glands secrete animal hormones directly into the blood that reach to the specific cells. Special type of molecules are present on the surface of cells to detect these hormones. These cells act according to the information that a particular hormone carries.

Question 2:
Why is the use of iodised salt advisable ?

Answer 2:
It is advised to use iodised salt because thyroid gland needs iodine to produce thyroxin hormone. Thyroxin hormone controls all the metabolic activities of our body like metabolism of carbohydrates, fats and protein etc. Due to the deficiency of thyroxin a disease called goitre is caused.

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

Answer 3:
Adrenaline is a hormone secreted when a person is frightened or mentally disturbed. When Adrenaline reaches heart, heartbeat will increase to increase blood supply to our muscles. Adrenaline also increases the breathing rate because of contraction of diaphragm and the rib muscles. Adrenaline rush also increases blood pressure and allows entry of more glucose into blood. These altogether occurs when our body respond to secretion of adrenaline into our blood.

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

Answer 4:
Diabetes is a condition where insulin hormone is produced less or stopped by pancreatic cells of a person. Insulin regulates blood glucose by converting extra glucose to glycogen. When insulin is not produced adequately person blood glucose level which leads to adverse effects. In order to maintain the insulin and blood glucose level diabetes patients are treated with injections of insulin.

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Exercise Questions (Page 126)

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

Answer 1:
Answer is d) cytokinin.
Cytokinin is a plant hormone whereas Insulin, Thyroxin, Oestrogen are the hormones produced by animals.

Question 2:
The gap between two neurons is called a
(a) dendrite
(b) synapse
(c) axon
(d) impulse

Answer 2:
Answer is (b) Synapse
Dendrite is a short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body.
An axon or nerve fiber is a long, slender projection of a nerve cell or neuron in vertebrates that typically conducts electrical impulses known as action potentials away from the nerve cell body. The function of the axon is to transmit information to different neurons, muscles, and glands.

Question 3:
The brain is responsible for
(a) thinking
(b) regulating the heart beat
(c) balancing the body
(d) all of the above

Answer 3:
Answer is (d) all the above
Brain is responsible for thinking, brain regulates the heartbeat, and it balance the body.

Question 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?

Answer 4:
Receptors are present throughout our body mainly sense organs. Receptors collect the information about changes that happen around us and send the signal to information to brain which render effector mechanism against the change. When receptors do not work properly, the environmental stimuli are not able to create nerve impulses and body does not respond.

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

Answer 5:
Nerve cell or neuron is the functional unit of nervous system. A nerve cell has three parts-
(i) cell body
(ii) dendrite
(iii) axon

Function : The function of nerve cells is to carry information in the form of electrical signals which are called nerve impulses. Cells receive stimulus to send it to spinal cord and brain and carry the message from brain to the target organ.

Question 6:
How does phototropism occur in plants ?

Answer 6:
The movement in any part of a plant due to light is called phototropism. The shoot of plant shows positive phototropism and roots show negative phototropism.
Phototropism in plants 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 appears to bend towards light.

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

Answer 7:
In case of a spinal cord injury, signals coming from the nerves as well as the signals coming to the receptors will be disrupted. Both these signals meet in a bundle in the spinal cord. Hence, both these signals get disrupted.

Question 8:
How does chemical coordination occur in plants?

Answer 8:
Chemical coordination in plants takes place with the help of plant hormones. In most of the regions where division takes place (meristematic regions) stimuli cells secrete chemical compounds (hormone). These substances identify the information by stimulating the other nearby cells and communicating the information.

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

Answer 9:
There are various organs in an organism. These organs must be carefully controlled and coordinated for the survival of an organisms. In the body of an organism various fluids are secreted from the glands of the endocrine system. These hormones are responsible for the overall growth and development of an organism. All others daily decision that includes voluntary and involuntary action are controlled by central nervous system (CNS).

Coordination is needed for all human activities we perform. Our nervous system receives information from surroundings which is processed and response is ilicited. The endocrine system (hormonal system) helps in integrating various metabolic activities like reproduction, development, and all reflex actions (cope up with various give up situations).

The hormonal system in plants helps in process of photosynthesis; they need carbon dioxide, water and sunlight. The stomatal opening in leaves opens up to allow in carbon dioxide gas, the roots bend towards water and the stem grows towards sunlight, the tendrils in climbing pants are supported by the hormonal system of the plant body.
Thus, we need of control and coordination system in an organisms.

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

Answer 10: