NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination

The Class 10 NCERT Solutions for Science Chapter 7 Control and Coordination includes all the intext and exercise questions. Class 10 Science Chapter 7 Control and Coordination NCERT questions and answers help students to clear their doubts and to obtain good marks in Class 10 board exam. All the solutions provided in this article are strictly based on the CBSE syllabus and curriculum.

Class 10 Science Chapter 7 NCERT Questions and Answers

Class 10 Science Chapter 7 Control and Coordination NCERT Questions and Answers are prepared by experts with a detailed explanation that will help students complete their assignments & homework. Having a good grasp over CBSE NCERT Solutions for Class 10 Science will further help the students in their preparation for board exams and other competitive exams such as NTSE, Olympiad, etc.

NCERT Solutions for Class 10 Science Chapter 7 Intext Questions

Intext Question (Page No. 119)

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

Answer:

Reflex action	Walking
It is the action which is performed automatically.	It is a response to the information transmitted by nerve to muscles of the legs. In this case, thinking is involved.
It is controlled and coordinated by spinal cord.	Brain instructs and controls leg muscles to move.
It is an involuntary action.	It is a voluntary action.

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

Answer: A very small gap that occurs between the last portion of axon of one neuron and the dendrite of the other neuron is known as a synapse. It acts as a one-way valve to transmit impulses in one direction only.This one-directional transfer of impulses occurs as the chemicals are produced in only one side of the neuron i.e., the axon’s side. From axon, the impulses travel across the synapse to the dendrite of the other neuron.

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

Answer: Cerebellum which is a part of Hind brain is responsible for Controls the motor functioning hence it is the part reengaged in the maintenance of posture and equilibrium of the body.

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

Answer: The thinking part of our brain is the forebrain. It has separate areas that are specialized for hearing, smelling, sight, taste, touch, etc. The forebrain also has regions that collect information or impulses from the various receptors. When the smell of an incense stick reaches us, our forebrain detects it. Then, the forebrain interprets it by putting it together with the information received from other receptors and also with the information already stored in the brain.

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

Answer: 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 the person to get awareness of the stimulus and prevent himself from that situation again.

Intext Question (Page No. 122)

Question 1: What are plant hormones?

Answer: Plant hormones or phytohormones are naturally-occurring organic substances. These are synthesized in one part of the plant body (in minute quantities) and are translocated to other parts when required. The five major types of phytohormones are auxins, gibberellins, cytokinins, abscisic acid and ethylene.

• Gibberellins help in the growth of the stem.
• Auxins help in the growth of the stem.
• Cytokinins promote cell division.
• Abscisic acid is one example of a hormone which inhibits growth.

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

Answer:

Movement of leaves of sensitive plant	Movement of a shoot towards light
It is a nastic movement which does not depend on the direction of stimulus applied.	It is a tropic movement which depends on the direction of stimulus applied.
The stimulus is touch.	The stimulus is light.
It is caused by the sudden loss of water from the swellings at the base of leaves.	It is caused by the unequal growth on the two sides of the shoot.
It is not a growth movement.	It is a growth movement.

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

Answer: Examples of plants growth hormones:
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: 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: Take two small beakers and label them as A and B. Fill beaker A with water. Now make a cylindrical-shaped roll from a filter paper and keep it as a bridge between beaker A and beaker B, as shown in the figure. Attach few germinating seeds in the middle of the filter paper bridge. Now, cover the entire set-up with a transparent plastic container so that the moisture is retained.

Observation: The roots of the germinating seeds will grow towards beaker A. This experiment demonstrates the phenomenon of hydrotropism

Intext Question (Page No. 125)

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

Answer: Chemical coordination takes place in animals with the help of hormones. Hormone is the chemical messenger that regulates the physiological processes in living organisms. It is secreted by glands. The regulation of physiological processes and control and coordination by hormones comes under the endocrine system. The nervous system along with the endocrine system in our body controls and coordinates the physiological processes.

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

Answer: 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: Adrenalin is a hormone secreted by the adrenal glands in case of any danger or emergency or any kinds of stress. It is secreted directly into the blood and is transported to different parts of the body. 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.

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

Answer: Insulin hormone regulates blood sugar levels. If this is not secreted in proper amounts, the sugar level in the blood rises. This causes many harmful effects.
To treat harmful effects of increased level of blood sugar, the diabetic patients are treated by giving injections of insulin.

NCERT Solutions for Class 10 Science Chapter 7 Exercise Questions

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 likely to arise?

Answer: Receptors are specialised cells located in our sense organs like ear, nose, skin, tongue and eyes. The function of receptors is to detect information from the environment. For example, olfactory receptors detect smell. If receptors do not work properly, the information obtained from the environment will be delayed to reach the spinal cord or brain. In this situation, the response to the environmental stimulus will be delayed causing harm to the body. For example, if skin receptors are damaged, and one accidentally touches a hot object, then his/her hands might get burn as the damaged receptor cannot perceive the external stimuli of heat and pain.

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

Answer: Neurons are the functional units of the nervous system. The three main parts of a neuron are axon, dendrite and cell body.

Functions of the three parts of a neuron:

• Axon: It conducts messages away from the cell body.
• Dendrite: It receives information from axon of another cell and conducts the messages towards the cell body.
• Cell body: It contains nucleus, mitochondria, and other organelles. It is mainly concerned with the maintenance and growth.

Question 6: How does phototropism occur in plants?

Answer: The movement of plant in response to light is called phototropism. Stem shows positive phototropism as follows:

When growing plants detect light, a hormone called auxin, synthesized at the shoot tip, helps the cells 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 cells 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: The reflex arc connections between the input and output nerves meet in a bundle in the spinal cord. In fact, nerves from all over the body meet in a bundle in the spinal cord on their way to the brain. In case of any injury to the spinal cord, the signals coming from the nerves as well as the signals coming to the receptors will be disrupted.

Question 8: How does chemical coordination occur in plants?

Answer: Plant growth, development and responses to the environment is controlled and coordinated by a special class of chemical substances known as hormones. Hormones are produced in one part of the plant and are transported to all the needy parts of the plant. The five major types of phytohormone are auxins, gibberellins, cytokinins, abscisic acid, and ethylene. These phytohormones are either growth promoters (such as auxins, gibberellins, cytokinins, and ethylene) or growth inhibitors such as abscisic acid.

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

Answer: The maintenance of the body functions in response to changes in the body by working together of various integrated body systems is known as coordination. All the movements that occur in response to stimuli are carefully coordinated and controlled. In animals, the control and coordination movements are provided by nervous and muscular systems. The nervous system sends messages to and away from the brain. The spinal cord plays an important role in the relay of messages. In the absence of this system of control and coordination, our body will not be able to function properly. For example, when we accidentally touch a hot utensil, we immediately withdraw our hand. In the absence of nerve transmission, we will not withdraw our hand and may get burnt.

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

Answer:

Reflex actions	Involuntary actions
Rapid automatic responses to a stimulus without the conscious involvement of the brain	Occurs without the consciousness of an organism
Controlled by spinal cord	Controlled by mid brain or medulla oblongata
Very quick and instantaneous	Relatively slower
May involve any muscle or a gland	Involves only smooth muscles
Can be conditioned	Cannot be influenced by external conditioning
Examples: Blinking of eyes, salivation	Examples: Beating of heart, blood circulation

Question 11: Compare and contrast nervous and hormonal mechanisms for control and coordination in animals.

Answer:

Nervous control	Hormonal Control
It is consists of nerve impulses between PNS, CNS and Brain.	It consists of endocrine system which secretes hormones directly into blood.
Here response time is very short.	Here response time is very long.
Nerve impulses are not specific in their action.	Each hormone has specific actions.
The flow of information is rapid.	The flow of information is very slow.

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:

Movement in a sensitive (mimosa) plant	Movement in legs of a human
The leaves of a sensitive plant like mimosa are sensitive to touch.	Leg is in control of nerve muscles.
It is not controlled by any part of the plant.	It is controlled by brain and spinal cord.
In this, cells change their shape on changing the amount of water in them.	Amount of water has no effect on the movement of muscles.
The movement in a sensitive plant are nastic movement.	The movement in our leg is due to voluntary nervous system.

Topics covered under Class 10 Science Chapter 7 Control and Coordination

Below we have listed the topics discussed in NCERT Solutions for Class 10 Science Chapter 7. The list gives you a quick look at the different topics and subtopics of this chapter.

Section in NCERT Book	Topics Discussed
7.1	Animals – Nervous System
7.1.2	Human Brain
7.2	Coordination in Plants
7.3	Hormones in Animals

NCERT Solutions for Class 10 Science Chapter 7 – A Brief Discussion

Chapter Overview: In keeping with the general principles of body organisation in multicellular organisms, specialised tissues are used to provide control and coordination activities. In animals, such control and coordination are provided by nervous and muscular tissues. But plants have neither a nervous system nor muscles. So in plants, cells change their shape for the conduction of information. Hormones also play an important role in coordination which has been discussed in the chapter briefly.