NCERT Exemplar Chapter 7 Control and Coordination Class 10 Science Solutions

NCERT Exemplar Class 10 Science Chapter 7 Control and Coordination Solutions

NCERT Exemplar Solutions for Class 10 Science Chapter 7 Control and Coordination covers all the important questions and answers as well as advanced level questions. It helps in learning about the Neuron, cell body, dendrites, Axon, Nerve ending, Nucleus, Reflex Actions, Reflex Arcs, Human Brain, Forebrain, Midbrain, Hindbrain, Cerebellum Medulla and Pons..

The NCERT Exemplar solutions for class 10 science is very important for board exams. NCERT Exemplar Solutions for Class 10 Science Chapter 7 Control and Coordination is provided by our experts. They prepared the best solutions which help the students in understanding the solutions in an easy way. This chapters also covers the other topics like plant hormones like gibberellins, auxins, Cytokinins Hormones in Animals, Thyroid hormone, Growth hormone, Insulin, Testosterone, Estrogen hormone and Adrenaline.

Chapter Name	Chapter 7 Control and Coordination
Book Title	NCERT Exemplar for Class 10 Science
Related Study	NCERT Solutions for Class 10 Science Chapter 7 Control and Coordination Revision Notes for Class 10 Science Chapter 7 Control and Coordination MCQ for Class 10 Science Chapter 7 Control and Coordination Important Questions for Class 10 Science Chapter 7 Control and Coordination
Topics Covered	MCQ Short Answers Questions Long Answers Questions

NCERT Exemplar Solutions for Chapter 7 Control and Coordination Class 10 Science

Multiple Choice Questions

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

Solution

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

A cell which is sensitive for the external stimulus such as light, taste, smell, etc. is known as a receptor cell.
For example: the photoreceptors detect light, gustatory receptors detect taste and the 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

Solution

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

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

3.  In a synapse, chemical signal is transmitted from

(a) dendritic end of one neuron to axonal end of another neuron
(b) axon to cell body of the same neuron
(c) cell body to axonal end of the same neuron
(d) axonal end of one neuron to dendritic end of another neuron

Solution

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

Electric impulse travels from the axon of one neuron to the dendrite of another neuron through a synaptic gap which consists of synapse.

4.  In a neuron, conversion of electrical signal to a chemical signal occurs at/in
(a) cell body
(b) axonal end
(c) dendritic end
(d) axon

Solution

(b) axonal end 

The electric impulse triggers the release of neuro transmitter at the axonal end. 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

Solution

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

Sensory neurons receive signals from the receptors. These signals are then sent to spinal cord. From the spinal cord, the signals reach the muscles through the motor neuron.

6. Which of the following statements are true?
(i) Sudden action in response to something in the environment is called reflex action
(ii) Sensory neurons carry signals from spinal cord to muscles
(iii) Motor neurons carry signals from receptors to spinal cord
(iv) The path through which signals are transmitted from a receptor to a muscle or a gland is called reflex arc 

(a) (i) and (ii)
(b) (i) and (iii)
(c) (i) and (iv)
(d) (i) , (ii) and (iii)

Solution

(c) (i) and (iv)

Sensory neurons carry signals from muscles to spinal cord.

7. Which of the following statements are true about the brain?
(i) The main thinking part of brain is hind brain
(ii) Centres of hearing, smell, memory, sight etc. are located in fore brain.
(iii) Involuntary actions like salivation, vomiting, blood pressure are controlled by the medulla in the hind brain
(iv) Cerebellum does not control posture and balance of the body 

(a) (i) and (ii)
(b) (i), (ii) and (iii)
(c) (ii) and (iii)
(d) (iii) and (iv)

Solution

(c) (ii) and (iii)

Forebrain is the thinking part of brain. Cerebellum controls the posture and balance of the body.

8. Posture and balance of the body is controlled by
(a) cerebrum
(b) cerebellum
(c) medulla
(d) pons

Solution

(b) cerebellum 

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

9. Spinal cord originates from
(a) cerebrum
(b) medulla
(c) pons
(d) cerebellum

Solution

(b) medulla

10. The movement of shoot towards light is
(a) geotropism
(b) hydrotropism
(c) chemotropism
(d) phototropism

Solution

(d) phototropism 

Growth of plant roots towards or away from moisture is called hydrotropism. Plant growth in response to gravitational force is called as geotropism. Growth of plant in response to 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 growth of stem

Solution

(c) inhibit growth 

Auxins increase the length of cells. Cytokinin promotes cell division and gibberlins promote growth of stem.

12. Which of the following is not associated with growth of plant?
(a) Auxin
(b) Gibberellins
(c) Cytokinins
(d) Abscisic acid

Solution

(d) Abscisic acid 

Abscisic acid inhibits the growth of plant.

 

13. Iodine is necessary for the synthesis of which hormone?
(a) Adrenaline
(b) Thyroxin
(c) Auxin
(d) Insulin

Solution

(b) Thyroxin

14. Choose the incorrect statement about insulin
(a) It is produced from pancreas
(b) It regulates growth and development of the body
(c) It regulates blood sugar level
(d) Insufficient secretion of insulin will cause diabetes

Solution

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

15. Select the mis-matched pair 
(a) Adrenaline : Pituitary gland 
(b) Testosterone : Testes 
(c) Estrogen : Ovary 
(d) Thyroxin : Thyroid gland 

Solution

(a) Adrenaline : Pituitary gland 

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

16. The shape of guard cells changes due to change in the
(a) protein composition of cells
(b) temperature of cells
(c) amount of water in cells
(d) position of nucleus in the cells

Solution

(c) amount of water in cells 

The guard cells turn turgid because of excess of water and they turn flaccid due to loss of water.

 

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

Solution

(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

Solution

(b) chemotropism 

Chemicals are released by ovules which in turn stimulate the growth of pollen tubes towards the ovules.

 

19. The movement of sunflower in accordance with the path of sun is due to
(a) phototropism
(b) geotropism
(c) chemotropism
(d) hydrotropism

Solution

(a) phototropism 

• Phototropism is the movement of shoot towards light is called phototropism.
• Geotropism is the plant growth in response to gravitational force.
• Growth of plant in response to chemical stimulus is called chemotropism.
• Hydrotropism is the growth of plant roots towards or away from moisture. 

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

Solution

(c) abscisic acid 

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

21. Which of the following statements about transmission of nerve impulse is incorrect?
(a) Nerve impulse travels from dendritic end towards 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

Solution

(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

Chemicals or neurotransmitters are released at axonal end not on dendritic end.

22. Involuntary actions in the body are controlled by
(a) medulla in fore brain
(b) medulla in mid brain
(c) medulla in hind brain
(d) medulla in spinal cord

Solution

(c) medulla in hind brain 

Medulla is present in hind brain.

23. Which of the following is not an involuntary action?
(a) Vomiting
(b) Salivation
(c) Heart beat
(d) Chewing

Solution

(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

Solution

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

The olfactory receptors get blocked during cold, and hence the person cannot differentiate smell.

 

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

Solution

(c) 

Dendrites of one neuron receive electrical impulse from the axonal end of another neuron. After this, the electrical impulse travels through the cell body, axon and finally 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) Thyroid gland requires iodine to synthesise thyroxin
(d) Thyroxin is also called thyroid hormone

Solution

(a) Iron is essential for the synthesis of thyroxin

Iodine is essential for the synthesis of thyroxin but not iron.

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

Solution

(b) Less secretion of growth hormone 

The overall growth of an organism is controlled by the growth hormone. No secretion of growth hormones leads to dwarfism.

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

Solution

(c) testosterone from testes and estrogen from ovary

The sex hormones are responsible for the secondary characters which 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

Solution

(d) his sugar level in blood was high

Due to non-functioning or lack of insulin hormone, a patient suffering from diabetes will have high blood glucose. Such patients are administered with insulin injection to regulate blood glucose.

30. The hormone which increases the fertility in males is called
(a) oestrogen
(b) testosterone
(c) insulin
(d) growth hormone

Solution

(b) testosterone

31. Which of the following endocrine glands is unpaired?
(a) Adrenal
(b) Testes
(c) Pituitary
(d) Ovary

Solution

(c) Pituitary 

The number of adrenal glands is two and they are present on top of each kidney. Testes are also paired gland in males. Ovary which produces the female sex hormone is also a paired gland. Pitutary gland is not paired and is present below the brain.

32. Junction between two neurons is called
(a) cell junction
(b) neuro muscular junction
(c) neural joint
(d) synapse

Solution

(d) synapse 

A structure which allows a neuron to pass an electric signal to the next neuron or effector cell is known as the synapse. Therefore, it is a junction between two neurons.

33. In humans, the 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

Solution

(d) nervous and endocrine systems 

The nervous system and the endocrine system control and regulate all the processes including reproductive, respiratory and digestive systems.

Short Answer Questions 

34. Label the parts (a), (b), (c) and (d) and show the direction of flow of electrical signals in Figure 7.2.

Solution
(a) Sensory neuron 

(b) Spinal cord 

(c) Motor neuron 

(d) Muscle

35. Name the plant hormones responsible for the following
(a) elongation of cells
(b) growth of stem
(c) promotion of cell division
(d) falling of senescent leaves.

Solution
(a) Auxin
(b) Gibberlin
(c) Cytokinin
(d) Abscisic acid

36. Label the endocrine glands in Figure 7.3.

Solution

(a) Pineal Gland 

(b) Pitutary gland 

(c) Thyroid gland 

(d) Thymus 

37. In Figure 7.4 (a), (b) and (c), which appears more accurate and why ?

Solution

Figure (a) is most appropriate. This is because the shoots are negatively geotropic and hence grow upwards whereas roots are positively geotropic and hence they grow downwards.

38. Label the parts of a neuron in Figure 7.5.

Solution

(a) Dendrite 

(b) Cellbody 

(c) Axon 

(d) Axon terminal 

39. Match the terms of Column (A) with those of Column (B) 

Column A	Column B
(a) Olfactory receptors	(i) Tongue
(b) Thermo receptors (temperature receptors)	(ii) Eye
(c)Gustatoreceptors	(iii) Nose
(d) Photoreceptors	(iv) Skin

Solution 

Column A	Column B
(a) Olfactory receptors	(iii) Nose
(b) Thermo receptors (temperature receptors)	(iv) Skin
(c)Gustatoreceptors	(i) Tongue
(d) Photoreceptors	(ii) Eye

40. What is a tropic movement ? Explain with an example. 

Solution

The tropic movements are the directional growth movements of plants due to external stimuli. The tropic movement can be either towards the stimulus, or away from it. For example, in phototropic movement, the shoots respond by bending towards light while roots respond by bending away from it. 

41. What will happen if intake of iodine in our diet is low?

Solution

The following might happen if the intake of iodine in our diet is low:

1. The release of thyroxin from thyroid gland will be less. Because of this protein, carbohydrate and fat metabolisms will be affected.
2. A person might suffer from goitre.

42. What happens at the synapse between two neurons?

Solution

The axonal end of one neuron releases certain chemical substances when they receive an electric signal. This chemical substance crosses the synapse and moves towards the dendritic end of next neuron generating another electrical signal.

43. Answer the following :
(a) Which hormone is responsible for the changes noticed in females at puberty?
(b) Dwarfism results due to deficiency of which hormone?
(c) Blood sugar level rises due to deficiency of which hormone?
(d) Iodine is necessary for the synthesis of which hormone?

Solution

(a) Oestrogen hormone is responsible for the changes noticed in females at puberty
(b) Dwarfism results due to deficiency of Growth Hormones.
(c) Blood sugar level rises due to deficiency of Insulin Hormone
(d) Iodine is necessary for the synthesis of Thyroxine Hormone

44. Answer the following :
(a) Name the endocrine gland associated with brain?
(b) Which gland secretes digestive enzymes as well as hormones?
(c) Name the endocrine gland associated with kidneys?
(d) Which endocrine gland is present in males but not in females?

Solution 

(a) Pituitary

(b) Pancreas

(c) Adrenal

(d) Testes

Long Answer Questions 

45. Draw the structure of a neuron and explain its function. 

Solution

Neuron is highly specialized cell responsible for the transmission of nerve impulse.

Soma also known as the cell body is a star shaped hair like structure. The hair like structures are called dendrites and they receive nerve impulses.

The tail of the nucleus is known as the axon. The axon ends in hair like structures which makes the nerve endings. Nerve endings relay nerve impulses.

Myelin sheath acts as an insulator around the axon. It insulates axons from the electrical impulses from the surroundings. Function of neuron is to process and transmit information from brain to all parts of the body.

46. What are the major parts of the brain ? Mention the functions of different parts. 
Solution

Functions of brain parts 

he functions of brain parts are as follows:

• Forebrain: It is the thinking part of the brain. Separate regions of the fore-brain are meant specialized for smelling, hearing, seeing and so on. The fore-brain has regions which receive sensory impulses from various receptors.
• Mid brain and Hind brain: They control the involuntary actions.
• Cerebellum: Controls the voluntary actions and maintains the posture and balance of the body.
• Cerebrum: Cerebrum is responsible for sensory processing.
• Medulla: It controls the involuntary functions.
• Pons: They regulates respiration and control involuntary action sensations such as touch and pain.
• Hypothalamus: It controls sleep and wake cycle.

47. What constitutes the central and peripheral nervous systems? How are the components of central nervous system protected?

Solution

The brain and the spinal cord constitute the central nervous system whereas the peripheral nervous system is composed of nerves which are outside the spinal cord. A well-developed system protects the components of the central nervous system. The brain is enclosed in a hard shell called the skull and the spinal cord is enclosed in vertebral column. Moreover, there is cerebrospinal fluid which protects the brain from mechanical shocks.

48. Mention one function for each of these hormones :
(a) Thyroxin
(b) Insulin
(c) Adrenaline
(d) Growth hormone
(e) Testosterone.

Solution 

(a) Thyroxin regulates carbohydrate, fat and protein metabolisms.

(b) Insulin regulates blood glucose levels.

(c) Adrenaline increases the heart rate and supply of blood to various organs.

(d) Growth hormone regulates growth and development.

(e) Testosterone controls the changes of body features associated with puberty in male.

49. Name various plant hormones. Also give their physiological effects on plant growth and development

Solution

The various plant hormones are:

• Auxin which is responsible for the elongation of cells.
• Gibberlin which is responsible for growth of stem and hence increases the girth of stem.
• Cytokinin promotes cell division in plants.
• Abscisic acid stops growth of the plant and it makes leaves and fruits fall from plant.

50. What are reflex actions? Give two examples. Explain a reflex arc.

Solution

Reflex action is the sudden involuntary movement in a voluntary organ; in response to a stimulus.

Some examples of reflex actions are:

(a) Moving your hand away from a hot iron plate.

(b) Blinking of eyes.

Reflex Arc:

The path of electrical impulse during a reflex action is known as reflex arc. It is composed of sensory neuron, spinal cord, motor neuron and muscle. Steps involved in reflex arc are:

•  The sensory neuron senses the signals from the stimulus and carries them to the spinal cord.
• The spinal cord processes the signals and sends a message through the motor neuron.
• Motor neuron transmits the signals to the effector muscle so that the muscle can act immediately.

51. “Nervous and hormonal systems together perform the function of control and coordination in human beings.” Justify the statement.

Solution

Control and coordination in human beings is influenced by the nervous system. The brain controls all the organelles and organ system. A network of neurons carry signals through neurotransmitters in the form of electric impulses to the brain and from the brain, this enables the control in human beings. Hormonal system consists of varieties of hormones secreted by various glands in our body. The functions of nervous system are coordinated by the hormonal system. The life processes are indirectly controlled by the hormones by feedback mechanism.

52. How does chemical coordination take place in animals ? 

Solution

Different hormones are secreted by the different endocrine glands. These hormones carried by the blood to specific tissues or organs called target tissues or target organs. The hormones trigger a particular biochemical or physiological activity in the target tissues. 

Example:
Adrenal gland secretes Adrenalin which reaches the heart, lungs and Gastro intestinal tract. Heart speeds up its pumping action so that more blood could be supplied to the limbs and facial muscles. But activity of the GI tract is slowed down to ensure better blood supply in limbs. Thus, adrenalin prepares the body for a fight or flight situation.

53. Why is the flow of signals in a synapse from axonal end of one neuron to dendritic end of another neuron but not the reverse?

Solution

A chemical substance is released when an electrical signal reaches the axonal end of a neuron. This chemical diffuses towards the dendrite end of next neuron where it generates an electrical impulse or signal. In this way at the axonal end, the electrical signal is converted into a chemical signal. These chemicals are absent at the dendrite end of the neuron and this is the reason why the electrical signal cannot be converted into chemical signal.