RBSE Solutions for Class 10 Science Chapter 7 Control and Coordination

Rajasthan Board RBSE Solutions for Class 10 Science Chapter 7 Control and Coordination Textbook Exercise Questions and Answers.

RBSE Solutions for Class 10 Science Chapter 7 Control and Coordination

RBSE Class 10 Science Chapter 7 Control and Coordination InText Questions and Answers

Page 119.

Question 1.
What are the differences between reflex action and walking?
Answer:
Differences between reflex action and walking:

Reflex action	Walking
1.  It is an involuntary action.	1. It is an voluntary action.
2. In this spinal cord and brain, both takes part.	2. It is controlled by brain.
3. Intensity of reflex action cannot be changed.	3. Can changed.
4. It has protective and ’ life significance.	4. In addition to life and protective importance, it perform

Question 2.
What happens at the synapse between two neurons?
Answer:
At the end of the axon, the electrical inpulse sets off the release of same chemicals. These chemicals cross the gap, or synapse, and start a similar electrical impulse in a dentrite of the next neuron.

Question 3.
Which part of the brain maintains posture and equilibrium of the body?
Answer:
The cerebellum part of the brain maintains the posture of body and equilibrium.

Question 4.
How do we detect the smell of an agarbatti (incense stick)?
Answer:
We can detect the smell of agarbatti by olfactory receptors situated inside nose. The message develop by the stimules of nerve ends situated in our nose, reach to fore brain part of brain and detect the smell of agarbatti.

Question 5.
What is the role of the brain in reflex action?
Answer:
Usually body reflex actions controlled by spinal cord and mid brain control the reflex action of head, neck and upper part of head. Medulla oblangata of hind brain regulate the actions like heart beat, respiration rate, coughing, sneezing, salivation, vomiting, sweeting, etc.

Page 122.

Question 1.
What are plant hormones?
Answer:
Phytohormones:
Special types of chemical develop in plants, which control or regulate the plant growth, development and responses, called plant hormones. They are also called growth regulators. In plants chiefly five type of hormones are present Auxin, Gibberellin, Cytokinin, 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:
Difference in movement of leaves of sensitive plant and movement of a shoot towards light.

Movement of Leaves of Sensitive plant	Movement of Shoot towards light
1. Movement in leaves on touching the sensitive plant.	1. Movement in stem is due to light stimulus
2. This type of movement is called seismonasty.	2.It is called phototropism.
3. It does not depend on the direction of stimulation.	3. It depends on the direction of stimulation.
4. It is caused by sudden release of water from the cell	4. It arises from uneven growth on both sides of the shoot.
5. This is not a growth process.	5. This is a growth process
6. It occurs at a rapid pace.	6. It occurs at a slow pace

Question 3.
Give an example of a plant hormone that promotes growth.
Answer:
Auxin is a plant hormone which increase the growth

Question 4.
How do auxins promote the growth of a tendril around the support?
Answer:
Tendrils are sensedve of touch i.e., they show thigmotropism movement. Whenever they come in contact of a object, then the auxin present in it diffuse to the opposite side (side away from touch), and the cells of other side start to elongate and tendril band to opposite direction. In this way tendril makes coil around the support and grow.

Question 5.
Design an experiment to demonstrate hydrotropism.
Answer:
Hydrotropism:
Growth movements in response to external stimulus of water are termed as hydrotropism. Roots grow towards moisture, so they are positively hydrotropic.
Experiment:
Take a pot, put a cork in the hole present at bottom and keep the pot full of water. Now keep this pot in the centre of a large wooden box containing saw dust. Place some soaked seeds in the saw dust a few centimeters away from the water pot. We observe that through cork slowely water trickles in saw dust and seeds start to germinate. The germinated seed grow against the effect of gravitional towards the water source. So it is clear that root show hydrotropism.

Page 125.

Question 1.
How does chemical coordination take place in animals?
Answer:
In animals chemical coordination takes place through hormones secreted by endocrine glands. These hormones secreted by special glands and reach to target cells in form of chemical messengers and control and coordinate their functions.

Question 2.
Why is the use of iodised salts advisable?
Answer:
It is advisable that use the iodised salts because iodine is necessary for the thyroid gland to make thyroxine hormone. Thyroxine regulates carbohydrate, protein and fat metabolism in our body so as to provide the best equilibrium for growth. In case iodine is deficient in our diet, thyroxine will not be synthesised and there is a possibility that we might suffer from goitre. One of the symptoms in this disease is a swollen neck or bulging of eye balls. To protect from this disease and to remove the deficiency of iodine in body, it is advised to use iodised salts.

Question 3.
How does our body respond when adrenaline is secreted into blood?
Answer:
Adrenaline:
Hormone directly secreted into blood and sent to different organs of the body. Adrenaline work on special tissue or target organs including heart. As a result, the heart beats increases, resulting in supply of more oxygen to our muscles. The blood supply of the digestive system and skin is reduced due to contraction of muscles around small arteries of these organs. This diverts the blood to our skeletal muscles.

The breathing rate also increases because of the contractions of the diaphragm and the rib muscles. All these responses together enable the animal body to be ready to deal with the situation.

Question 4.
Why are some patients of diabetes treated by giving injections of insulin?
Answer:
Pancreas produce the insulin hormone. It helps to control the sugar level in blood. If it is not secreted in proper amounts, the sugar level in the blood rises causing many harmful effects.
So doctor’s give injection of insulin to diabetic patients, so this sugar level in blood may be controlled.

RBSE Class 10 Science Chapter 7 Control and Coordination Textbook Questions and Answers

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

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

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

Question 4.
What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likey to arise?
Answer:
In our body there are some special cells which receive the various types of stimules happens in external environment, called receptor or sense organs. The receptor organs receive the stimulus and then through sensory nerves send to central nervous system. We detect smell by olfactory receptors, detect taste by gustatory receptors, detect touch by touch receptors, detect sound and balance by phono receptors. If receptors do not work properly then above sense can not be received and sometimes odd conditions may develop.

Example:
On touching to hot object, if stimulus of heat not received by central nervous system through sense organs then hand may bum. In normal condition due to reflex action on touching to hot object the stimulus of temperature reach to spinal cord through sensory nerves and send to functional muscles by motor nerves. On contraction of functional muscles the hand moves from hot object.

Question 5.
Draw the structure of a neuron and explain its function.
Answer:
Nerve cell:
It is the basic unit to transmit the messages. It is specially long. This information, acquired at the end of the dendriti tip of a nerve cell, sets off a chemical reaction that creates an electrical impulse. This impuluse travels from the dendrite to the cell body, and then along the axon to its end. At the end of the axon, the electrical impulse sets off the release of some chemicals. These chemical cross the gap, or synapse, and start a similar electrical impulse in a dendrite of the next neuron. A similar synapse finally allows delivery of such impulses from neurons to other cells, such as muscles cells or gland.

Question 6.
How does phototropism occur in plants?
Answer:
Phtotropism:
Movement of plant stem towards the light is known as phototropism. Shoot system show positive phototropism and roots negative phototropism. When growing plant detect light, a hormone called auxin, synthesised at the shoot tip, helps the cell to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cell to grow longer on the side of the shoot which is away from light. Thus the plant appears to bend towards light.

Question 7.
Which signals will get disrupted in case of a spinal cord injury?
Answer:
On injury of spinal cord there will be disruption in getting the following indications:
(1) There will be disruption in providing the way for sensory impulses towards brain.
(2) There will be disruption in providing the way for motor impulses from brain.
(3) Disruption in conducting and regulating such reflex actions in which brain is not related.

Question8.
How does chemical coordination occur in plants?
Answer:
Plants chemical coordination takes place by hormones. There are secretion of different hormones by stimulus cells in plants. Different plant hormones help to coordinate growth, development and responses to environment. They are synthesised at places away from where they act and simply diffuse to the area Of action. For example plant hormones synthesised at apical part of the plant reach the different parts and develop cell enlargement, apical dominance and in growth of roots. Cytokinin hormone promote the cell division. Abscisic acid is the hormone which inhibits the growth. It increases the rate of leaf fall in autumn season. Ethylene help in ripining the fruits.

Question 9.
What is the need for a system of control and coordination in an organism?
Answer:
The body of organisms is made up of cells. These cells makes group and differentiated into tissues, different tissues combine to form organs. Different organs perform their own work in right time so they can work efficiently. Thus there should be some type of control on them so that they can work coordinately.

For example, when we eat food then our eyes see that where the food is kept, nose detect the smell of food, our hand take food aiid bring into mouth and our muscles of jaw and with the help of teeth food is chewed. All activities takes place with a coordination method and out of these any activity due to some reason not take place then interruption occur in nutrition process. So in organism there is need of control and coordination system.

Question 10.
How are involuntary actions and reflex actions different from each other?
Answer:
Differences in involuntary and reflex actions

Invoulantry actions	Reflex actions
1. They are control­led by mid brain and hind-brain.	1.These activities controlled by central nervous system.
2. They did not hap­pen suddenly.	2. Happen suddenly.
3. Sometimes there is a gap in between stimulu and response.	3. They quickly happen i.e., no gap in between them.
4. It takes place by smooth muscles.	4. It takes place by voluntary muscles, and glands.
5. These are not affected by external barriers.	5. They may be conditioned.
6. Example: Activity of heart.	6. On pricking the needle pulling the hand.

Question 11.
Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.
Answer:
Comparison and contrast nervous and hormonal mechanisms for control and coordination in animals as under:

Nervous Mechanism	Hormonal Mechanism
1. This central nervous system consists of the nerve impulses between the penpheral nervous system.	1. It is caused by hormones secreted by endocrine glands.
2. It has very short response time.	2. It has long response time.
3. Neural impulses are not specialized in function.	3. Each hormone has a specific function.
4. The flow of information in it is very tast.	4. The flow of information in it is slow.
5. The emergence of a neural impulse depends on he presence of stimulation.	5. The secretion of hormone is regulated feedback by the mechanism.
6. Through this, control of growth and development is less.	6. This system controls growth and development.

Question 12
What is the difference between the manner in which movement takes place in a sensitive plant and the movement in our legs?
Answer:
Difference in movements of sensitive plant and movement in our leg Nerves take part i.e., nerves take message and go

Movement in sensitive plant	Movement in Leg
1. Movement in sensitive plant lakes place on shock or touch.	1. Movement in leg takes place on accord our heart desire or on necessity.
2. Lack of specific tissue for conduction .of information.	2. Nerves take part i.e., nerves take message and go for the movement of leg.
3. This movement is due to flaccid condition of parenchyma of pulvinus.	3. Beni and spreading of leg done by help of muscles.
4. The movement present in sensitive plant is called thigmotropism.	4. Movement in leg is called voluntary movement.
5. Special proteins are not present in plant cells for movement.	5. Special protein are found in muscle cells for movement.