NCERT Solutions Class 10 Science Chapter 7 Control and Coordination
NCERT Solutions Class 10 Science Chapter 7 Control and Coordination: National Council of Educational Research and Training Class 10 Science Chapter 7 Solutions – Control and Coordination. NCERT Solutions Class 10 Science Chapter 7 PDF Download.
NCERT Solutions Class 10 Science Chapter 7: Overview
Board |
NCERT |
Class |
10 |
Subject |
Science |
Chapter |
7 |
Chapter Name |
Control and Coordination |
Topic |
Exercise Solutions |
NCERT Solutions Class 10 Science Chapter 7 – Control and Coordination
Questions within in the boxes:
Page 119
1.) What is the difference between a reflex action and walking?
Ans.
Refelx action | Walking |
Is a spontaneous or rapid involuntary action | Is a voluntary action and its performance depends on the will of a person |
Is occured through the spinal cord | It is controlled by the brain |
It cannot be controlled | Walking can be changed or its speed can be modified |
Occurs during the emergency situation | It occurs during normal situation. |
2.) What happens at the synapse between two neurons?
Ans. The synapse is the an empty space which is present between the two different nerve cells. At the synapse, a chemical substance is produced at the end of axon of one of the neurons and this chemical substance reaches to the other neurons with the help of the dendrite present on it. Therefore, the information signal or the impulse is got transmitted through one neuron to other neurons through the synapse.
3.) Which part of the brain maintains posture and equilibrium of the body?
Ans. Cerebellum of the brain maintains posture and equilibrium of the body.
4.) How do we detect the smell of an agarbatti (incense stick)?
Ans. The smell of an agarbatti can be detected with the help of special types of nerve cells called olfactory receptors present in our nose which sends electrical signal from nose to our brain.
5.) What is the role of the brain in reflex action?
Ans. There is no role of the brain in a reflex action as the reflex actions are directly controlled by the spinal cord.
Page 122
1.) What are plant hormones?
Ans. Plant hormones are the chemicals synthesized within the plant body that help to coordinate growth, development and responses to the environment. Ex- auxin, ethylene, etc.
2.) How is the movement of leaves of the sensitive plant different from the Movement of a shoot towards light?
Ans. Movement of leaves of the sensitive plant is different from the
Movement of a shoot towards light as the movement of leaves of the sensitive plant is known as a nastic movement, which is not dependent on the direction of the stimuli. Whereas, the movement of shoot towards light is known is a tropic movement as this movement is depending on the direction of sunlightlight.
3.) Give an example of a plant hormone that promotes growth.
Ans. Auxin is a plant hormone that promotes growth.
4.) How do auxins promote the growth of a tendril around a support?
Ans. Auxins are the plant hormone/ phytohormones which are synthesized at the shoot tip of the plant body. Auxin helps the cells to grow at the shoot tips.
When a tendril comes in contact with a support, phytohormone auxin stimulates faster growth of the cells on the opposite side of the tendril, as a result of the unbalanced growth on two sides of the tendril, tendrils cells coil around the support.
5.) Design an experiment to demonstrate hydrotropism.
Ans.
Page 125
1.) How does chemical coordination take place in animals?
Ans. Chemical coordination in animals takes place with the help of hormones which are the chemical compounds secreted by the endocrine glands of the endocrine system. Hormones controls and regulates the overall growth of the body and the development of animals.
2.) Why is the use of iodised salt advisable?
Ans. Thyroid glands need iodine as a raw material to produce the hormone thyroxine which, controls the basal metabolic rate of the body and activities carried out in our body such as metabolism of carbohydrates, fats and protein etc. Also, due to lack of iodine causes a disease called goitre which makes the thyroid gland to swell.
3.) How does our body respond when adrenaline is secreted into the blood?
Ans. The adrenal gland secretes adrenaline directly into the blood. During the event of stress or emergency, adrenaline is released into the blood in larger quantities. Our body shows reaction when it is secreted into the blood which are as follows:
- Heart beat of the person increases.
- It also raises the pressure of the blood.
- Increased heart beat causes more oxygen supply towards the muscles.
- Breathing rate also get increase.
4.) Why are some patients of diabetes treated by giving injections of insulin?
Ans. Insulin hormone regulates the level of sugar present in the blood which is secreted by pancrease. If it is not secreted in proper quantity, then the sugar level rises in our blood, causing many harmful effects on our health as it occurs in diabetic persons. Hence, in order to keep the insulin level in the blood at normal level, some patients of diabetes are treated by giving injections of insulin.
Exercise:
1.) Which of the following is a plant hormone?
(a) Insulin
(b) Thyroxin
(c) Oestrogen
(d) Cytokinin.
Ans. (d) Cytokinin
Hint: Insulin, Thyroxin and Oestrogen are hormones released in the animal systems. Whereas, Auxin, Cytokinins, Giberellin, Ehylene are the plant hormones. Alternative d is the correct answer.
2.) The gap between two neurons is called a
(a) dendrite.
(b) synapse.
(c) axon.
(d) impulse.
Ans. (b) synapse
Hint: synapse is the gap between two neurons whereas dendrite and axon are the part of neuron cells. Impulse is a message that can be transmitted through neuron.
3.) The brain is responsible for
(a) thinking.
(b) regulating the heart beat.
(c) balancing the body.
(d) all of the above.
Ans. (d) all of the above
Ans. thinking, regulating the heart beat and balancing the body all are the functions of brain.
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?
Ans. Receptors help us to detect the signals and then they send it to the brain in the form of electrical signals. If receptors do not work properly, they will not detect any input, leading to harm for our body in a dangerous situation.
Alternative Answer –
The information from environment, is detected by our receptors, which are located in all-over the parts in the form of sens organs like skin,nose,eye,ear, tongue. In that taste will be detected by gustatory receptors and smell will be detected by olfactory receptor. The fore-brain is main part for thinking in brain when the sensory impulses are received from the receptor which are present in different parts of the body to fore-brain in the form of electrical signals. In case these receptors will damaged then there is no sensory impulses are received from particular body part to fore-brain this might be cause serious problem for body.
5.) Draw the structure of a neuron and explain its function.
Ans. The function of neuron is to pass the information and send appropriate signals to the rest parts of the body from the brain.
Alternative Answer –
When the information are detected from receptors to our nerve cells, it send input for fore-brain through neurones,in other words we can say neuron is a network of nerve cells and it is a structural and functional unit of nervous system. The neuron contains three major parts which is cells body, dendrites and axons. When anyone receptor receive an information the neurones will receive the information in that neuron send electric signal to dendrite and the signal will pass through dendrite to cell body and cell-body send the signal to axon and finally axon will send the electric signal to next receiving neuron.
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6.) How does phototropism occur in plants?
Ans. Phototropism is the directional movement of a plant in response to light. The shoot of plant body responds by bending towards light and its roots respond by bending away from the light.
The phototropism occurs as follows:
- When sunlight falls on the plant body, the auxin hormone gets synthesised at the tip and it get spreads uniformly down the body and due to equal concentration of auxin, stem grows straight.
- When sunlight fells on only one side of the plant body and other side remains unexposed to sunlight, the auxin diffuses towards the shady side of shoot. The concentration of auxin is not uniform and it stimulates the cells to grow longer. And the stem appears to bend towards the source of light.
Alternative Answer –
When the plant is grow, when its growing movement is towards the direction of light or sunlight then it is known as phototropism. In this process the plants steam growing movement is towards the direction of sunlight called positively phototropics and the plants roots growing movement is opposite direction of the sunlight called negative phototropics. And this positive and negative phototropics are totally depends on auxin which is the harmone of the plant. The data of auxin is when Sunlight is coming from one side of the plant, then the auxin stimulate the cells to grow the shoot on the side which is away from the sunlight, that’s way the plant appears to bend towards the sunlight.
7.) Which signals will get disrupted in case of a spinal cord injury?
Ans. Injury to spinal cord will disrupt the passing down of the somatic motor impulses through it to different parts of the body.
Alternative Answer –
When there is an injury in the spinal cord, when we are physically stimulated, the signals sent from the receptors to the effectors are interrupted and the spinal cord injury affects the reflex action. When the receptor and effector signals meet in the bundle of the spinal cord, the spinal cord interrupts both of those signals and interferes with the peripheral nervous system that exists the brain.
8.) How does chemical coordination occur in plants?
Ans. Chemical coordination occurs in plants with the help of plant hormones/phytohormones that are secreted by plants.
Alternative Answer –
The process in which plants are grow with the help of its hormones then its called chemical coordination. The auxin, gibberellins, Cytokinins, abscisic acid are some hormones which are present in the plant. In which the auxin hormone is help to grow the plant. Plants also need a signal which stop its growing then an hormone called abscisic acid which hormone duty is when a specific part of the plant is grow completely this hormone is send the signal to stop the growing, for example when leaf is completely grow then it stop its growth due to abscisic acid. And an hormone like auxins called gibberellins, this hormone duty is to grow the steam of the plant and Cytokinins is also a hormone of the plant which promotes the cell division of the plant.
9.) What is the need for a system of control and coordination in an organism?
Ans. An organism needs control and coordination system for the following reasons :
to carry on normal functioning of all the systems in an organism.
- to get all the impulses from the surrounding environment and act accordingly.
- To carry out voluntary and involuntary actions precisely.
- To think on various situations and take decisions.
Alternative Answer –
In body nerves and muscular tissues are provides the control and coordination system. In our body there are billions of nerves cells and trillion of cells are present. When some activity is done in environment arround our body the activity is detected by nerve cells. The receptor which are present in all over the body like skin, and others are receive the signal and send the signal to fore-brain, and fore-brain which is main part for thinking is control the control and coordination system and it respond to the corresponding action. Generally we can say that control and coordination system is very important to listen and respond to the action going on arround us.
10.) How are involuntary actions and reflex actions different from each other?
Ans. Involuntary actions are the actions over which we do not have any control or will. Such type of actions are controlled directly by our brain. for example- beating of heart etc.
Reflex actions: Occur unkowingly, produced in response to the stimulus. it is controlled by the our spinal cord and brain have no direct role in their control.
for example, removal of hand when touched to an hot object.
Alternative Answer –
In our body without our control some movements are done by our muscular parts then the actions called involuntary action. And the action is controlled by medulla oblongata which is the part present inside the brain, for example vomiting, vomiting is an process in which there is no conscious control of our body therefore it is an involuntary action. Where as in our body there are sudden and spontaneous action are done by our stimula then the actions are called reflex action. For example coughing, coughing is a defensive reflex action done by suddenly and spontaneously therefore it is an reflex action.
11.) Compare and contrast nervous and hormonal mechanisms for control and Coordination in animals.
Ans.
Nervous control | Hormonal control |
Occurs with the help of neurons. | Occurs with the help of endocrine glands. |
Response is quick and sudden. | Response is slow but long lasting |
Control takes place by electrical impulses | Chemical signals are used for communication |
Signals travels through neurons | Signals travels through blood |
Alternative Answer –
Nervous system |
Hormonal system |
1. The information signals are send through neurones. | The information signals are send through blood cells. |
2. Sensory receptors are included in the nervous system | Sensory receptors are not included in the hormonal system |
3. The information sending speed is very fast. | The information sending speed is slow. |
4. The action of the nervous system is voluntary or involuntary action. | The action of the hormonal system is involuntary action |
5. The response power of the nervous system is very fast. | The response power of the hormonal system is slow. |
12.) What is the difference between the manner in which movement takes place in a Sensitive plant and the movement in our legs?
Ans.
Movement in sensitive plant | Movement in legs |
Occurs as a response to touch | Is a voluntary action |
Special type of tissue is not required for the transfer of information | Transfer of information occurs through CNS and PNS |
Special type of proteins are absent in the plant cells. | Special types of proteins do help in contraction of muscles which relax after completion of the work |
Alternative Answer –
Movement in sensitive plant |
Movement in our legs |
1. When we touch sensitive plant we can notice its movement. | The movement of our leg is can be controlled in voluntary action. |
2. Plant hormones are controls the movement of the plant. | The cerebellum which is present in our hind-brain is control the movement of our legs. |
3. There is no protein present in plant for movement. | There are special protein are present in animals body for the movement of muscles of the animals. |
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