Chapter 7 Control And Coordination NCERT Exemplar for class 10 Science

NCERT Exemplar Class 10 Science Chapter 7 Control and Coordination provide you with surprise bag filled with answers and detailed explanations to the questions provided in the NCERT Exemplar book. Students can prepare for their board exams, class tests and other class assignments by downloading these solutions in PDF for free. Thorough knowledge of concepts and regular practice will help you score full marks in their exams. It is very important for the students to solve and practice with the help of NCERT to get familiar with the new pattern of the questions from the chapter Control and Coordination.

In our day-to-day lives, we can relate ourselves with different movements that are a direct result of a change in a certain environment. However, these movements are carefully controlled by all living beings. Thus, in Chapter 7 of NCERT Exemplar Solutions, students will learn about Control and Coordination and what are the factors that are responsible for such motions. Students will also study about reflex actions and other movements in plants and the nervous system in detail. Thus, to help students fully understand the concepts in this chapter and to master all the topics, the free NCERT exemplar for class 10 Chapter 7 is provided here.

Students can download Class 10 Science Chapter 7 NCERT Exemplar Solutions from below

1. Which of the following statements is correct about receptors?

(a) Gustatory receptors detect taste, while olfactory receptors detect smell

(b) Both gustatory and olfactory receptors detect smell

(c) Auditory receptors detect smell, and olfactory receptors detect taste

(d) Olfactory receptors detect taste, and gustatory receptors smell

Soln:

The answer is (a) Gustatory receptors detect taste, while olfactory receptors detect smell

Explanation:

A receptor is a cell which is sensitive for the external stimulus such as light, taste, and smell. For example, Photoreceptors detect light, Gustatory receptors detect taste, and Olfactory receptors detect smell.

2. Electrical impulse travels in a neuron from

(a) Dendrite → axon → axonal end → cell body

(b) Cell body → dendrite → axon → axonal end

(c) Dendrite → cell body → axon → axonal end

(d) Axonal end → axon → cell body → dendrite

Soln:

The answer is (c) Dendrite → cell body → axon → axonal end

Explanation:

Stimulus is received by dendrites which are transmitted to cyton through the axon. Stimulus reaches the terminal branches called the axonal end, from where they are transmitted to another neuron.

3. In a synapse, a chemical signal is transmitted from

(a) dendritic end of one neuron to the axonal end of another neuron

(b) axon to the cell body of the same neuron

(c) cell body to the axonal end of the same neuron

(d) axonal end of one neuron to the dendritic end of another neuron

Soln:

The answer is (d) the axonal end of one neuron to the dendritic end of another neuron.

Explanation:

The electric impulse travels from the axon to the dendrite of another neuron through a synaptic gap which consists of SYNAPSE.

4. In a neuron, the conversion of electrical signal to a chemical signal occurs at/in

(a) cell body

(b) axonal end

(c) dendritic end

(d) axon

Soln:

The answer is (b) axonal end

Explanation:

At the axonal end, the electric impulse triggers the release of neurotransmitters. These chemicals enter the dendrite of another neuron to transmit the signal.

5. Which is the correct sequence of the components of a reflex arc?

(a) Receptors→ Muscles→ Sensory neuron→ Motor neuron→ Spinal cord

(b) Receptors→ Motor neuron → Spinal cord → Sensory neuron → Muscle

(c) Receptors → Spinal cord → Sensory neuron → Motor neuron → Muscle

(d) Receptors → Sensory neuron → Spinal cord → Motor neuron → Muscle

Soln:

The answer is (d) Receptors → Sensory neuron → Spinal cord → Motor neuron → Muscle

Explanation:

Sensory neurons receive signals from receptors. These signals are sent to the spinal cord, which reaches Muscles through the motor neuron.

6. Which of the following statements is true?

(i) Sudden action in response to something in the environment is called reflex action

(ii) Sensory neurons carry signals from the spinal cord to muscles

(iii) Motor neurons carry signals from receptors to the spinal cord

(iv) The path through which signals are transmitted from a receptor to a muscle or a gland is called the reflex arc

(a) (i) and (ii)

(b) (i) and (iii)

(c) (i) and (iv)

(d) (i), (ii) and (iii)

Soln:

The answer is (c) (i) and (iv)

Explanation:

Sensory neurons carry signals from muscles to the spinal cord hence statements ii) and iv) are wrong statements.

7. Which of the following statements is true about the brain?

(i) The main thinking part of the brain is the hindbrain

(ii) Centres of hearing, smell, memory, sight etc., are located in the forebrain.

(iii) Involuntary actions like salivation, vomiting, and blood pressure are controlled by the medulla in the hindbrain

(iv) Cerebellum does not control the posture and balance of the body

(a) (i) and (ii)

(b) (i), (ii) and (iii)

(c) (ii) and (iii)

(d) (iii) and (iv)

Soln:

The answer is (c) (ii) and (iii)

Explanation:

Forebrain is the thinking part of the brain hence statement i) is wrong. Cerebellum controls posture and balance of the body hence statement iv) is wrong

8. Posture and balance of the body is controlled by

(a) cerebrum

(b) cerebellum

(c) medulla

(d) pons

Soln:

The answer is (b) cerebellum

Explanation:

Cerebrum is responsible for sensory processing. Medulla controls involuntary functions. Pons regulates respiration and controls involuntary action sensations such as touch and pain.

9. Spinal cord originates from

(a) cerebrum

(b) medulla

(c) pons

(d) cerebellum

Soln:

The answer is (b) medulla

10. The movement of the shoot towards light is

(a) geotropism

(b) hydrotropism

(c) chemotropism

(d) phototropism

Soln:

The answer is (d) phototropism

Explanation:

The growth of plant roots towards or away from moisture is called hydrotropism. Plant growth in response to gravitational force is called geotropism. The growth of plants in response to the chemical stimulus is called chemotropism.

11. The main function of abscisic acid in plants is to

(a) increase the length of cells

(b) promote cell division

(c) inhibit growth

(d) promote the growth of stem

Soln:

The answer is (c) inhibit growth

Explanation:

Auxins increase the length of cells. Cytokinins promote cell division. Gibberellins promote the growth of the stem.

12. Which of the following is not associated with the growth of a plant?

(a) Auxin

(b) Gibberellins

(c) Cytokinins

(d) Abscisic acid

Soln:

The answer is (d) Abscisic acid

Explanation:

Abscisic acid inhibits the growth of plants; hence, it is not associated with the growth of the plant.

13. Iodine is necessary for the synthesis of which hormone?

(a) Adrenaline

(b) Thyroxin

(c) Auxin

(d) Insulin

Soln:

The answer is (b) Thyroxin

14. Choose the incorrect statement about insulin

(a) It is produced from pancreas

(b) It regulates the growth and development of the body

(c) It regulates blood sugar level

(d) Insufficient secretion of insulin will cause diabetes

Soln:

The answer is (b) It regulates the growth and development of the body

15. Select the mismatched pair

(a) Adrenaline: Pituitary gland

(b) Testosterone: Testes

(c) Estrogen: Ovary

(d) Thyroxin: Thyroid gland

Soln:

The answer is (a) Adrenaline: Pituitary gland

Explanation:

Adrenaline is secreted by the Adrenal gland, and the Pituitary gland produces TSH, FSH and GSH hormones.

16. The shape of guard cells changes due to changes in the

(a) protein composition of cells

(b) temperature of cells

(c) amount of water in cells

(d) position of the nucleus in the cells

Soln:

The answer is (c) amount of water in cells

Explanation:

Excess of water will turn guard cells turgid, and loss of water will turn guard cells flaccid.

17. The growth of tendril in pea plants is due to

(a) effect of light

(b) effect of gravity

(c) rapid cell divisions in tendrillar cells that are away from the support

(d) rapid cell divisions in tendrillar cells in contact with the support

Soln:

The answer is (c) rapid cell divisions in tendrillar cells that are away from the support.

18. The growth of pollen tubes towards ovules is due to

(a) hydrotropism

(b) chemotropism

(c) geotropism

(d) phototropism

Soln:

The answer is (b) chemotropism

Explanation:

Chemicals released by ovules stimulate the growth of pollen tubes towards ovules.

19. The movement of the sunflower in accordance with the path of the sun is due to

(a) phototropism

(b) geotropism

(c) chemotropism

(d) hydrotropism

Soln:

The answer is (a) phototropism

Explanation:

The movement of shoot towards light is called phototropism.

Plant growth in response to gravitational force is called geotropism.

The growth of plant in response to chemical stimulus is called chemotropism.

The growth of plant roots towards or away from moisture is called hydrotropism.

20. The substance that triggers the fall of mature leaves and fruits from plants is due to

(a) auxin

(b) gibberellin

(c) abscisic acid

(d) cytokinin

Soln:

The answer is (c) abscisic acid

Explanation:

Abscisic acid forms a layer of abscission. This layer disconnects the living tissue of the leaf from the other parts.

21. Which of the following statements about the transmission of nerve impulse is incorrect?

(a) Nerve impulse travels from the dendritic end towards the axonal end

(b) At the dendritic end, electrical impulses bring about the release of some chemicals, which generate an electrical impulse at the axonal end of another neuron

(c) The chemicals released from the axonal end of one neuron cross the synapse and generate a similar electrical impulse in a dendrite of another neuron

(d) A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells

Soln:

The answer is (b) At the dendritic end, electrical impulses bring about the release of some chemicals, which generate an electrical impulse at the axonal end of another neuron.

Explanation:

Chemicals or neurotransmitters are released at the axonal end, not on the dendritic end. Hence, statement b) is incorrect.

22. Involuntary actions in the body are controlled by

(a) medulla in forebrain

(b) medulla in midbrain

(c) medulla in hindbrain

(d) medulla in the spinal cord

Soln:

The answer is (c) medulla in hindbrain.

Explanation:

Medulla is present only in the hindbrain.

23. Which of the following is not an involuntary action?

(a) Vomiting

(b) Salivation

(c) Heartbeat

(d) Chewing

Explanation:

The answer is (d) Chewing

24. When a person is suffering from severe cold, he or she cannot

(a) differentiate the taste of an apple from that of an ice cream

(b) differentiate the smell of a perfume from that of an agarbatti

(c) differentiate red light from green light

(d) differentiate a hot object from a cold object

Soln:

The answer is (b) differentiate the smell of a perfume from that of an agarbatti.

Explanation:

During cold olfactory receptors get blocked hence we cannot differentiate smell.

25. What is the correct direction of the flow of electrical impulses?

Soln:

The answer is c)

Explanation:

The dendrites of a neuron receive electrical impulse from the axonal end of another neuron. After that, the electrical impulse travels through the cell body, axon, to the axonal end.

26. Which statement is not true about thyroxin?

(a) Iron is essential for the synthesis of thyroxin

(b) It regulates carbohydrates, protein and fat metabolism in the body

(c) The thyroid gland requires iodine to synthesise thyroxin

(d) Thyroxin is also called the thyroid hormone

Soln:

The answer is (a) Iron is essential for the synthesis of thyroxin

Explanation:

Iodine is essential for the synthesis of thyroxin but not iron hence statement a) is wrong

27. Dwarfism results due to

(a) Excess secretion of thyroxin

(b) Less secretion of growth hormone

(c) Less secretion of adrenaline

(d) Excess secretion of growth hormone

Soln:

The answer is (b) Less secretion of growth hormone

Explanation:

Growth hormones are responsible for the overall growth of an organism. When there is no secretion of growth hormones, it leads to dwarfism.

28. Dramatic changes of body features associated with puberty are mainly because of the secretion of

(a) oestrogen from testes and testosterone from ovary

(b) estrogen from adrenal gland and testosterone from pituitary gland

(c) testosterone from testes and estrogen from ovary

(d) testosterone from thyroid gland and estrogen from pituitary gland

Soln:

The answer is (c) testosterone from testes and estrogen from ovary.

Explanation:

These are the sex hormones responsible for the secondary character that appear after puberty. Males secrete testosterone, and females secrete estrogen.

29. A doctor advised a person to take an injection of insulin because

(a) his blood pressure was low

(b) his heart was beating slowly

(c) he was suffering from goitre

(d) his sugar level in blood was high

Soln:

The answer is (d) his sugar level in blood was high.

Explanation:

Patients suffering from diabetes will have high blood glucose due to non-functioning or lack of insulin hormone. Such patients are administered with insulin injections to regulate blood glucose.

30. The hormone which increases fertility in males is called

(a) oestrogen

(b) testosterone

(c) insulin

(d) growth hormone

Soln:

The answer is (b) testosterone

31. Which of the following endocrine glands is unpaired?

(a) Adrenal

(b) Testes

(c) Pituitary

(d) Ovary

Soln:

The answer is (c) Pituitary

Explanation:

Adrenal glands are two, which are present on top of each kidney. Testes is a paired gland in males which produces male sex hormones. Ovary is a paired gland in females which produces female sex hormones. The pituitary gland is an independent gland present below the brain. It is called as master gland, as it secretes major of the hormones.

32. The junction between two neurons is called

(a) cell junction

(b) neuromuscular junction

(c) neural joint

(d) synapse

Soln:

The answer is (d) synapse

Explanation:

A synapse is a structure that allows a neuron to pass an electric signal to the next neuron or effector cell. Hence it is a junction between two neurons.

33. In humans, life processes are controlled and regulated by

(a) reproductive and endocrine systems

(b) respiratory and nervous systems

(c) endocrine and digestive systems

(d) nervous and endocrine systems

Soln:

The answer is (d) nervous and endocrine systems.

Explanation :

Reproductive, respiratory and digestive systems have no role to play in the control and regulation of life processes. It is the nervous system and the endocrine system that control and regulates all the processes, including the reproductive, respiratory and digestive systems.