NCERT Exemplar Solution Class 10 Science Chapter 7

NCERT Exemplar Solution Class 10 Science Chapter 7 Control and Coordination all Questions Answer Solution. NCERT Exemplar Class 10 Science Chapter 7 Solution PDF.

NCERT Exemplar Solution Class 10 Science Chapter 7: Overview

NCERT Exemplar Solution Class 10 Science Chapter 7

Board

NCERT
Topic

Exemplar Problem Solution

Class

10
Subject

Science

Chapter

7
Chapter Name

Control and Coordination

NCERT Exemplar Solution Class 10 Science Chapter 7 Control and Coordination

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

Answer: Answer is A. Because these gustatory receptors are present in mouth and more specifically on tongue, therefore able to detect taste and olfactory receptors detect smell, because they are present in nose (nasal cavity).

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

Answer: Answer is C. In between two neurons the space is present called synaptic cleft. The way of electrical impulses follows a route isDendrite cell body axon axonal end.

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

Answer: Answer is D. Neuron starts from axon and ends on dendrite, therefore chemical signal is transmitted from axonal end of one neuron to dendritic end of another neuron.

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

Answer: Answer is B. It occurs at axonal end. At the one end of neuron.

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

Answer: Answer is D. The correct sequence of the components of a reflex arc are Receptors Sensory neuron Spinal cord Motor neuron Muscle.

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)

Answer: Answer is C.

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)

Answer: Answer is C.Centers of hearing, smell, memory, sight etc are located in fore brain. Involuntary actions like salivation, vomiting, blood pressureare controlled by the medulla in the hind brain

8.) Posture and balance of the body is controlled by

(a) cerebrum

(b) cerebellum

(c) medulla

(d) pons

Answer: Answer is B. The site for controlling Posture and balance of the body is cerebellum.

9.) Spinal cord originates from

(a) cerebrum

(b) medulla

(c) pons

(d) cerebellum

Answer: Answer is B. It originates from medulla.

10.) The movement of shoot towards light is

(a) geotropism

(b) hydrotropism

(c) chemotropism

(d) phototropism

Answer: Answer is D. The bending or movement of plant towards light called phototropism.

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

Answer: Answer is C. There is no role of ABA in plant development.

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

(a) Auxin

(b) Gibberellins

(c) Cytokinins

(d) Abscisic acid

Answer: Answer is D. ABA does not play any role in growth of plant.

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

(a) Adrenaline

(b) Thyroxin

(c) Auxin

(d) Insulin

Answer: Answer is B. For the synthesis and growth of thyroxine, iodine is necessary.

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

Answer: Answer is B. Insulin is produced by pancreas, and its main function is to regulate the blood sugar level, so option is incorrect.

15.) Select the mis-matched pair

(a) Adrenaline : Pituitary gland

(b) Testosterone: Testes

(c) Estrogen : Ovary

(d) Thyroxin : Thyroid gland

Answer:Answer is A. Other options are correctly matched with hormones except adrenaline is produced by adrenal gland.

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

Answer: Answer is C. When water present in guard cells its size and shape increases, and when water lost from guard cell, its size and shape decreases.

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

Answer: 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

Answer: Answer is B. It is characterized by chemicals, so the process is called as chemotropism.

19.) The movement of sunflower in accordance with the path of sun isdue to

(a) phototropism

(b) geotropism

(c) chemotropism

(d) hydrotropism

Answer: Answer is A. The growth of plant in direction of light called phototropism.

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

(a) auxin

(b) gibberellin

(c) abscisic acid

(d) cytokinin

Answer: Answer is C.The substance that triggers the fall of mature leaves and fruitsfrom plants is due to ABA.

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

Answer: Answer is B. All the options are correct except B.

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

Answer: Answer is B. The center for involuntary action is midbrain.

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

(a) Vomiting

(b) Salivation

(c) Heart beat

(d) Chewing

Answer: Answer is D. All other activities are involuntary except 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

Answer: Answer is B.When a person is suffering from severe cold, he or she cannot determine smell of things.

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

Answer: Answer is C.

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

Answer: Answer is B. Thyroxine need iodine and its also called as thyroid hormone, so B is the not correct answer.

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

Answer: Answer is B. Dwarfism results due to less secretion of growth hormone

28.) Dramatic changes of body features associated with puberty aremainly 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

Answer: Answer is C. The male sex hormone called testosterone secreted from testes. The female sex hormone called estrogen secreted from ovary.

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

Answer: Answer is D. Because his sugar level in blood was high. Insulin regulate the amount of sugar in the blood.

30.) The hormone which increases the fertility in males is called

(a) oestrogen

(b) testosterone

(c) insulin

(d) growth hormone

Answer: Answer is B. The male sex hormone called testosterone secreted from testes and it is responsible to increase the fertility in males.

31.) Which of the following endocrine glands is unpaired?

(a) Adrenal

(b) Testes

(c) Pituitary

(d) Ovary

Answer: Answer is C All the three glands are paired except pituitary gland.

32.) Junction between two neurons is called

(a) cell junction

(b) neuro muscular junction

(c) neural joint

(d) synapse

Answer: Answer is D. The space between two neurons called synapse.

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

Answer: Answer is D. Because both the nervous and endocrine systems are work in co-ordination.

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.

Answer:

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.

Answer:

(a) elongation of cells: Auxin

(b) growth of stem : Gibberellin

(c) promotion of cell division: Cytokinin

(d) falling of senescent leaves : Abscisic Acid

36.) Label the endocrine glands in Figure 7.3.

Answer:

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

Fig. 7.4

Answer: The answer is diagram A is accurate, because any roots will grow in response to gravity and water. Therefore the bending of roots towards the soil.

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

Fig. 7.5

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

 

Answer:

Column A Answer
(a) Olfactory receptors Nose
(b) Thermo receptors (temperature receptors) Skin
(c) Gustatoreceptors Tongue
(d) Photoreceptors Eye

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

Answer: The tropic movement can be defined as the movement given by plants in response to any external factors such as light, gravity, touch, water or chemicals. The movement of plant in response to any stimulus called tropic movement. These movement can be positive or negative. Positive movement can be defined as when plant moves towards the direction of stimulus called positive movement. The negative movement is when plant moves away from the stimulus called negative movement.

For example : The plant sunflower grows towards the direction of sunlight.

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

Answer: Iodine is necessary for development of thyroid gland, but normal quantity of every substance is important. If intake of iodine in our diet is low then it leads to swallowing of thyroid gland.

42.) What happens at the synapse between two neurons?

Answer: The synapse is the space in between two neurons, where transmission of nerve impulses takes place that means transmission of signal occurs.

43.) Answer the following:

(a) Which hormone is responsible for the changes noticed infemales 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?

Answer:

(a)hormone is responsible for the changes noticed in females at puberty are estrogen and progesterone.

(b) Dwarfism results due to deficiency of Growth hormone.

(c) Blood sugar level rises due to deficiency of insulin hormone

(d) Iodine is necessary for the synthesis of thyroid 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?

Answer:

(a) The endocrine gland associated with brain is pituitary gland.

(b) Pancreas secretes digestive enzymes as well as hormones.

(c) Adrenal gland is the endocrine gland associated with kidneys.

(d) Testis is the endocrine gland is present in males but not in females.

Long Answer Questions

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

Answer:

The functional unit of nervous system is neuron. Neurons are also called as nerve cells, because they carrying the information in the form of signal from various parts of the body to the brain and again transmitting information from brain to the target organ. As we can see in the diagram the neuron contains all the cellular organelles such as the cell body, dendrites that means extensions which arise from cell body, presence of axon, myelin sheath and axon terminals.

46.) What are the major parts of the brain? Mention the functions ofdifferent parts.

Answer: The nervous system can be classified into 2 categories. The two major parts of nervous system are Central Nervous System (CNS) and Peripheral Nervous System (PNS).

The central nervous system is the major part of the nervous system, all the activities of the body carried out by the CNS. It contains the different parts of the sensory part and make the control and coordination in the body.

The Central Nervous System is made up of brain and spinal cord.

  • A network of neurons is present in brain stem called as spinal cord.
  • Spinal cord contains spinal nerves.
  • It is the center for various types of reflex actions.

Peripheral Nervous System is a part of nervous system, which work in coordination with central nervous system. The PNS (Peripheral Nervous System) is divided into 2 divisions such as somatosensory nervous system (SNS) and Autonomic Nervous system (ANS).

1.) Nervous system carry out control and coordination of the body.

2.) It transports the signal that is send and receive the signals from various organs of the body.

3.) Maintains homeostasis in the body. Homeostasis can be defined as maintaining the internal environment constant in the body.

4.) It acts as center for learning, walking, thought, speech and hearing.

47.) What constitutes the central and peripheral nervous systems? Howare the components of central nervous system protected?

Answer: Somatosensory Nervous System (SNS) : It is also called as sensory nervous system. It contains 2 types of neurons such as somatic neuron and sensory neuron. The somatic neuron shows the efferent neurons functions and is displays voluntary regulation. The sensory neurons shows the afferent neuron that means it sense the signal. It releases the signal in the form of acetylcholine.

Autonomic nervous system : Autonomic nervous system is divided into two parts such as sympathetic nervous system and parasympathetic nervous system. The sympathetic nervous system will work when post ganglion neuron release the hormones epinephrine and nor epinephrine. Therefore the sympathetic nervous system releases the epinephrine or nor epinephrine due to presence of receptors on their membrane. The two types of receptors are present are called as alpha androgenic receptor and beta androgenic receptor.

The parasympathetic nervous system releases acetylcholine, in reverse to this actylcholine gives 2 types of responses such as excitatory response and inhibitory response. Excitatory response present on skeletal muscle whereas inhibitory response are present on glands and heart.

Brain : The human brain is made up of 3 parts namely forebrain, midbrain and hindbrain.

The circulating fluid in surround the brain is CSF that is cerebral spinal fluid. CSF acts as shock absorber from mechanical injury. The brain is protected by 3 layers namely, dura mater, arachnoid mater and pia mater. These 3 protective layer called as meninges.

  • Dura mater : It is the outermost layer of brain, also called as tough mother.
  • Arachnoid mater : It is the middle layer of brain.
  • Pia mater : It is the innermost layer of brain, also called as soft mother.

48.) Mention one function for each of these hormones :

(a) Thyroxin

(b) Insulin

(c) Adrenaline

(d) Growth hormone

(e) Testosterone.

Answer:

(a) Thyroxin: Thyroxin hormone carry out the maintenance and metabolism of protein, carbohydrates and fats.

(b) Insulin: It is helpful in regulating the amount of blood sugar level.

(c) Adrenaline: The hormone is responsible for the fight and flight stimulus.

(d) Growth hormone: It regulates the growth and development.

(e) Testosterone: The hormone present in male responsible for production of sperms.

49.) Name various plant hormones. Also give their physiological effectson plant growth and development.

Answer: Plant hormones also called as phytohormones because phyto means plants. These plant hormones are the complex organic compounds which have ability to synthesize in plant body. These hormones synthesized at one site and perform their functions at another site.

These plant hormones can major role such as growth and development.

There are 5 types of major hormones such as

1) Auxin :

1.)The major function is cell elongation.

2.) It have ability of apical dominance. The term apical dominance means it inhibits lateral bud formation.

3.) It breaks the dormancy.

4.) It helps in delay of leaf and fruit abscission (falling off).

2) Cytokinin:

1.) Cytokinin helps in cell division.

2.) Cytokinin carry out seed germination.

3.) Cytokinin responsible for nutrient mobilization or movement.

4.) It helps in chloroplast division.

3) Gibberellin

1.) It promotes cell division.

2.) Induce cell elongation.

3.) Helps in stem/ internode elongation.

4.) They inhibit flowering in short day plants.

4) Ethylene

1.) It carry out fruit ripening.

2.) It breaks the bud and seed dormancy.

3.) It gives the triple response to plants that is inhibition and swelling of hypocotyl, inhibition of root elongation and apical hook formation.

4.) It increases the leaf senescence.

5) Abscisic acid

1.) ABA causes maturation of embryo.

2.) ABA increases bud dormancy.

3.) Helps in induction of seed germination.

4.) ABA causes to increase the leaf senescence.

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

Answer: Reflex action can be defined as the sudden reaction to a particular stimulus. It is involuntary action. The involuntary action can be defined as the action which is not in our control. For example: When we touch the hot substance our hand automatically gets backward due to presence of sensory neurons and reflex arc. One more example if any insects bites to any site of the body then immediate reaction occurs to that stimulus. It is called as reflex arc.

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

Answer: Endocrine system can be defined as the complex mesh of glands which are orchestrate the activities like growth, reproduction and development by releasing hormones. Hormone is a chemical substance which they travel through the blood to target cell. The study of endocrine system called as endocrinology. Functions of endocrine system are:

1.) To maintain the homeostatic condition of the body.

2.) Play major role in growth, development and reproduction.

3.) The endocrine system regulate the physiological activities of the body.

4.) The endocrine system releases hormones also in stressed condition.

This endocrine system work in coordination with nervous system, because when any stimulus present on skin it is sensed by nervous system called as sensory neurons and in response to this endocrine system releases hormones.

52.) How does chemical coordination take place in animals?

Answer: The chemical coordination take place in animals through the release of hormones.

Hormones play major role in the body, they are the chemical substances can be travel through the blood.The endocrine gland produces some chemicals called hormones.Hormones will diffuse and bind target cell.The target cell must have specific receptor binds to which hormone binds.There are various types of hormones.

  • Hypothalamus is the upper part of brain, present near the pituitary gland as we can see in the diagram.
  • When any stress condition occurs in the body, stress condition means other than normal condition arises in the body at that time, the first response is given by hypothalamus.
  • Hypothalamus gives response means, in response to a particular stimulus hypothalamus releases some ‘releasing hormones’.
  • These releasing hormones will act on the pituitary gland.
  • Pituitary gland is master of all organs, this gland releases various types of hormones.
  • The pituitary gland is divided into 2 types such as anterior pituitary gland and posterior pituitary gland.
  • Pituitary gland will act and will convert the stress condition to normal condition in the body.

Anterior pituitary gland :

  • This Anterior pituitary gland is considered to be master gland because its secretion or release of this gland leads to production of many other hormones.
  • FSH (Follicle Stimulating Hormone) and LH (Leutenizing Hormone) will orchestrate the production of estrogen and progesterone.
  • GH (Growth Hormone) responsible for the growth of cells and to increase height of person until a particular age.
  • ACTH (Adreno Cortico Tropic Hormone), this hormone is responsible for adrenal cortex formation. The adrenal gland which is present at the upside of kidney.
  • TSH (Thyroid stimulating hormone) this hormone will stimulate the growth of thyroid gland and this gland will produce the hormone thyroxine, which maintains the health of thyroid gland.
  • The prolactin hormone produced in case of feeding mothers, it will help in stimulation for production of milk.

Posterior pituitary gland :

  • Posterior pituitary gland releases two types of hormones such as ADH and oxytocin.
  • ADH (Anti Diuretic Hormone), will be responsible for maintaining the water concentration in the body.
  • ADH also called as vasopressin.

Oxytocin hormone is released in woman at the time of birth, for the contraction of uterus.

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

Answer: The flow of signals in a synapse from axonal end of oneneuron to dendritic end of another neuron but not the reverse because when signal passes axonal end it will release chemicals and send to the dendritic end and then dendritic end will work, therefore this action cannot take place in reverse direction.

Updated: May 4, 2021 — 9:11 pm

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