INTEXT QUESTIONS AND ANSWERS of NCERT Class 10 Science Chapter 7 Control and Coordination
PAGE – 119
- What is the difference between a reflex action and walking?
Ans : Reflex action is a spontaneous involuntary or automatic nerve mediated response to a stimulus produced at the unconscious level. But walking is a voluntary action , which requires our thinking and is within our control .
2. What happens at the synapse between two neurons ?
Ans : A synapse is a gap between the two neurons . At the synapse , the electrical signals are converted into chemicals that can easily cross over the gap and pass on to the next neurons where it is again converted into an electrical signal.
NCERT Class 10 Science Chapter 7 Control and Coordination
3. Which part of the brain maintains posture and equilibrium of body ?
Ans : Cerebellum .
This is the back of the brain . It co ordinates voluntary muscle movements and helps to maintain posture , balance and equilibrium .
4. How do we detect the smell of an agarbatti ( incense sticks ) ?
Ans : Smell of an incense stick is detected by the olfactory receptors present in the nose . The information is transmitted to olfactory lobe located in the fore brain which interprets the information .
5. What is the role of brain in reflex action ?
Ans : in a reflex action , the brain plays no part . The spinal cord , which reacts without thinking about how to respond to stimuli , is in charge of these automatic actions . They receive information from all parts of the body and integrate it.
NCERT Class 10 Science Chapter 7 Control and Coordination
PAGE – 122
- What are plant hormones ?
Ans : Plant hormones are chemical compounds present in very low concentration in plants . Plant hormones help to co – ordinate growth , development and responses to the environment .
2. How is the movement of leaves of sensitive plant is different from movement of a short towards light ?
Ans: The type of movement of leaves of the sensitive plant is known as a nastic movement . But the movement of shoot is diectional towards light.
This type of movement does not depend on the direction of stimuli. The movement of the shoot towards light is due to growth controlled by growth hormone .
3. Give an example of plant hormone that promotes growth .
Ans : Auxin.
Auxin is a plant hormone that promotes growth .
NCERT Class 10 Science Chapter 7 Control and Coordination
4. How do auxin promote growth of a tendril around a support ?
Ans : Some plants like the pea plant climb up other plants or support by means of tendrils. These tendrils are sensitive to touch . When a tendril comes in contact with a support, auxin stimulates faster growth of the cells on the opposite side that’s why the tendril forms a coil around the support . This causes the tendril to circle around the object and thus cling to it . It is due to accumulation of auxin .
NCERT Class 10 Science Chapter 7 Control and Coordination
5. Design an experiment to demonstrate hydrotropism .
Ans : Growth movements in response to the stimulus of moisture are termed as hydrotropic movements.
place some ready to germinate seeds of pea in moist sawdust in a shallow box whose bottom has been replace by a wire gauze .
Keep the apparatus undisturbed for 2-3 days. Keep the sawdust moist. After some time radicles will pass through the sieves . Then the radicles curve upwards again to enter into the moist sawdust ,the roots are positively hydrotropic and the curvature is more than that due to entropic effect .
NCERT Class 10 Science Chapter 7 Control and Coordination
PAGE – 125
1. How does chemical co ordination take place in animals ?
Ans : Chemical co ordination takes place in animals with the help of chemical messengers called as hormones . They are secreted by endocrine glands. The hormones are carried by the blood to the site of action . The hormones are consumed during their action . Hormones regulate the growth , development and homeostasis of the animals .
2. Why is the use of iodized salt advisable ?
Ans : Iodine is essential for the thyroid gland to produce thyroxin hormone. Thyroxin regulates carbohydrate , protein and fat metabolism in the body so as to provide the best balance for growth . Iodine is essential for the synthesis of thyroxin . In case iodine is deficient in our diet,there is a possibility that we might suffer from goitre. This deficiency disease is known as goitre . Therefore iodized salt is advised.
3. How does our body respond when adrenaline is secreted into the blood ?
Ans : When secreted in large amounts it speeds up the heartbeat and hence supplies more oxygen to the muscles. The breathing rate also increases due to contractions of diaphragm and rib muscles . It also increases the blood pressure. All these responses enable the body to deal with any stress or emergency .
4. What are some patient of diabetes treated by giving injections of insulin ?
Ans : Insulin is a hormone which is produced by the pancreas and helps in regulating blood sugar levels . If it is not secreted in proper amounts the sugar level in the blood rises causing many harmful effects .
NCERT Class 10 Science Chapter 7 Control and Coordination
EXERCISES
- Which of the following is a plant hormone ?
- Insulin
- Thyroxin
- Oestrogen
- Cytokinin
Ans : d. Cytokinin
2. The gap between two neurons is called a
- Dendrite
- Synapse
- Axon
- Impuls
Ans : b. Synapse
3. The brain is responsible for
- Thinking
- Regulating the heart beat
- balancing the body
- All of the above
Ans: d. All of the above
NCERT Class 10 Science Chapter 7 Control and Coordination
4.What is the function of receptors in our body ? Think of a situation where receptors do not work properly . What problems are likely to arise ?
Ans: Receptors are present in all parts of the body for example in the ski , eyes , nose, tongue, etc.
The function of receptors is to detect information from the environment.
If receptors do not detect the information there will not be any co – ordination. It may lead to accidents. Body response will not be there .
5. Draw a structure of a neuron and explain its function .
Ans : Structure of neuron :
NCERT Class 10 Science Chapter 7 Control and Coordination
Function :
- Dendrites of a neuron collect information from the receptor.
- Axon conducts information as electrical impulse.
- Terminal arborization pass the information as chemical stimulus at synapse for onward transmission.
NCERT Class 10 Science Chapter 7 Control and Coordination
6. How does phototropism occur in plants ?
Ans : Phototropism is the directional response of a plant that allows the plant to grow towards or some cases away from the light. These directional or tropic movements can be either towards the stimulus or away from it , so, in two different kind of phototropic movement, shoots respond by bending towards light while roots respond by bending away from it.
7. Which signals will get disrupted in case of a spinal cord injury ?
Ans: Reflex action will be disturbed because reflex arcs are located in the spinal cord . so, the quick responses needed to safe guard the body will not take place . The delayed responses may cause harm to the body.
As both of these signals meet in a bundle in the spinal cord , so, if there is any spinal cord injury then botyh of these signals will be disrupted.
NCERT Class 10 Science Chapter 7 Control and Coordination
8. How does chemical co ordination occur in plants ?
Ans : Chemical co ordination occurs in plants with the help of phytohormones or plant hormones secreted by plants. Auxin, cytokinin, gibberellin , abscisic acid are plant hormones. These hormones regulate the growth and development of the plants. They also regulates various metabolic activities in the plants. All growth processes are regulated by one or more phytohormones acting synergistically or antagonistically.
NCERT Class 10 Science Chapter 7 Control and Coordination
9. What is the need for a system of control and co ordination in an organism ?
Ans : An organism needs control and co ordination system for the following functions :
- To save the body of the organisms from the harmful changes in the environment.
- To control the speed of voluntary and involuntary actions .
- To have the capability to think and learn for responding to any stimuli.
10. How are involuntary actions and reflex actions different from each other ?
Ans : Reflex actions are the spontaneous responses by voluntary organs but involuntary actions are by the involuntary organs.
The difference between involuntary actions and reflex actions are :
| Involuntary actions | Reflex actions |
| i. Involuntary actions are the actions which are not controlled by our will. | i. Reflex actions are the sudden action in response to something. |
| ii. They do not need any kind of stimulus to work. | ii. They required stimulus for its action |
| iii. These actions are regulated by the brain. | iii. These actions are regulated by the spinal cord. |
| iv. They do not involve skeletal muscle. | iv. They do involve skeletal muscle. |
| v. these actions are performed throughout one’s life. | v. These actions are produced in response to an event of an emergency. |
| vi. This action may be quick or slow. | vi. Reflex actions are always quick. |
| vii. For example : The beating of the heart is an involuntary action . salivating when food is put in the mouth. | vii. For example : Immediate withdrawl of hands upon touching a hot cup of tea. closing the eyes , when bright light is focused. |
NCERT Class 10 Science Chapter 7 Control and Coordination
NCERT Class 10 Science Chapter 7 Control and Coordination
11. Compare and contrast the nervous and hormonal mechanism for control and co ordination in animals .
Ans:
| Nervous System | Hormonal System |
| i. It consists of the central nervous system (CNS) and peripheral nervous system(PNS) | i. It consists of endocrine glands. |
| ii. Nervous system has a network of nerves spread through out the body. | ii. Hormonal system does not has such a network. |
| iii. Neural responses are quick and short lived. | iii. Hormonal effects are slow but are long term. |
12. What is the difference between the manner in which movement takes place in a sensitive plant and the first movement in our legs ?
Ans : The movement in the sensitive plant is involuntary action , but the change in our legs is a voluntary action.
Plants have some specialized protein for the movement in sensitive plants. But animals have some concentrated protein . This protein helps the muscles to move.
There are two types of tissues helps to transfer the information in the animal cell, but there is no cell is available in a plant cell.
Our legs are provided with nerves which have connection with muscles. To lift the leg, the brain passes information to nerves.
NCERT Class 10 Science Chapter 7 Control and Coordination
NCERT Class 10 Science Chapter 7 Control and Coordination
NCERT Class 10 Science Chapter 7 Control and Coordination
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NCERT Class 10 Science Chapter 7 Control and Coordination
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