NCERT Exemplar Class 10 Science Solutions

Chapter 07-Control and Coordination-MCQs

Multiple Choice Questions (MCQs)
Q.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. a)
Explanation: Gustatory receptors are the taste receptors which are present on the surface of tongue in the form of taste buds. Olfactory receptors help to sense the smell and are located over the roof of nasal cavity.
Q.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. (c)
Explanation: Dendrite receives signals from sensory receptors or other neurons. Axon serves to conduct the nerve impulse away from the cell body.
Q.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. (d)
Explanation: Neurotransmitters are released from axon of one neuron to dendrite of next neuron.
Q.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. (b)
Explanation: Neurotransmitters are released from axonal end of one neuron and transmit the electrical signal to dendrite of next neuron.
Q.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. d)
Explanation: A stimulus received by the receptors present on skin, is transmitted to the sensory neuron which carries it to the central nervous system (the spinal cord and brain). A motor neuron carries the message from the central nervous system to the effector which could be a muscle, a gland or both.
Q.6. Which of the following statements are true?
(i) Sudden action in response to something in the environment is caller 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 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. (c)
Explanation: Reflex arc is a simple nervous pathway and consists of sensory receptor, afferent neuron, centre, efferent neuron and effector organ. Automatic, quick and innate response to particular stimuli that is mediated by reflex arc is known as reflex action.
Q.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. (c)
Explanation: Cerebrum is the center for higher thought processes required for learning, memory, language and speech. Medulla is the center for regulation of involuntary actions.
Q.8. Posture and balance of the body is controlled by
a) Cerebrum
b) Cerebellum
c) Medulla
d) Pons
Answer. (b)
Explanation: Cerebellum coordinates the voluntary movements of skeletal muscles as well as posture, balance and equilibrium.
Q.9. Spinal cord originates from
a) Cerebrum
b) Medulla
c) Pons
d) Cerebellum
Answer. (b)
Explanation: Spinal cord begins in continuation with medulla and extends downwards.
Q.10. The movement of shoot towards light is
a) Geotropism
b) Hydrotropism
c) Chemotropism
d) Phototropism
Answer. (d)
Explanation: Growth movement of plants in response to light is called as phototropism.
Q.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. (c)
Explanation: Abscisic acid (ABA) is a growth retardation hormone.
Q.12. Which of the following is not associated with growth of plant?
a) Auxin
b) Gibberellins
c) Cytokinins
d) Abscisic acid
Answer. (d)
Explanation: Abscisic acid (ABA) is a growth retardation hormone.
Q.13. Iodine is necessary for the synthesis of which hormone?
a) Adrenaline
b) Thyroxin
c) Auxin
d) Insulin
Answer. (b)
Explanation: Hormones of thyroid gland have iodine as their structural component.
Q.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. (b)
Explanation: Insulin regulates blood sugar level.
Q.15. Select the mis-matched pair
a) Adrenaline—Pituitary gland
b) Testosterone—Testes
c) Estrogen—Ovary
d) Thyroxin—Thyroid gland
Answer. (a)
Explanation: Adrenaline is secreted by the adrenal gland.
Q.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. (c)
Explanation: Shape of guard cell is maintained by its turgidity which in turn is regulated by water content of these cells.
Q.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. (c)

Explanation: Growth movements in response to touch are known as thigmotropism.
Q.18. The growth of pollen tubes towards ovules is due to
a) Hydrotropism
b) Chemotropism
c) Geotropism
d) Phototropism
Answer. (b)
Explanation: Stigma serves as landing platform for pollens as well as secretes chemical substances that attract pollen tube through style towards ovary.
Q.19. The movement of sunflower in accordance with the path of sun is due to
a) Phototropism
b) Geotropism
c) Chemotropism
d) Hydrotropism
Answer. (a)
Explanation: Growth movement of plants in response to light is called as phototropism.
Q.20. The substance that triggers the fall of mature leaves and fruits from plants is due to
a) Auxin
b) Gibberellins
c) abscisic acid
d) Cytokinin
Answer. (c)
Explanation: Abscisic acid serves to form of layer of abscission.
Q.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. (b)
Explanation: Neurotransmitters are released from axon of one neuron to dendrite of next neuron.
Q.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. (c)
Explanation: Medulla is part of hind brain and controls the involuntary action.
Q.23. Which of the following is not an involuntary action?
a) Vomiting
b) Salivation
c) Heart beat
d) Chewing
Answer. (d)
Explanation: The actions that are not under our direct control are called as involuntary actions.
Q.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. (b)
Explanation: Cold thickens the mucus in nasal passages and block passage of odour to olfactory receptor cells.
Q.25. What is the correct direction of flow of electrical impulses?

Answer. (c)
Explanation: Electrical impulse travel in following direction:
Impulse → Dendrite → Cell body → axon → dendrite of next neuron
Q.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. (a)
Explanation: Thyroxin contains iodine in its structure.
Q.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. (b)
Explanation: Growth hormone regulates normal growth and development of individual.
Q.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
Answer. (c)
Explanation: Testosterone and estrogen are male and female sex hormones respectively.
Q.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. (d)
Explanation: Insulin regulates the blood sugar level.
Q.30. The hormone which increase the fertility in males is called
a) Oestrogen
b) Testosterone
c) Insulin
d) Growth hormone
Answer. (b)
Explanation: Testosterone is the male sex hormone necessary for sperm production.
Q.31. Which of the following endocrine glands is unpaired?
a) Adrenal
b) Testes
c) Pituitary
d) Ovary
Answer. (c)
Explanation: Pituitary gland is unpaired gland.
Q.32. Junction between two neurons is called
a) Cell junction
b) Neuro muscular junction
c) Neural joint
d) Synapse
Answer. (d)
Explanation: Synapse is the junction between two neurons.
Q.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. (d)
Explanation: Nervous system and endocrine system work together to maintain homeostasis.