Control and Coordination MCQ 1
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
Ans. (c) Amount of water in cells
Explanation: Excess amount of water results in guard cells becoming turgid,
while lack of water results in flaccidity of guard cells.
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
Ans. (c) rapid cell divisions in tendrillar cells that are away from the support
Explanation: Due to this, there is more growth on portion away from support.
This results in tendrils getting twined around the support.
18. The growth of pollen tubes towards ovules is due to
(a) hydrotropism
(b) chemotropism
(c) geotropism
(d) phototropism
Ans. (b) chemotropism
Explanation: Ovules release certain chemicals which stimulate the growth of
pollen tubes towards ovules.
19. The movement of sunflower in accordance with the path of sun is due to
(a) phototropism
(b) geotropism
(c) chemotropism
(d) hydrotropism
Ans. (a) phototropism
Explanation: Refer to explanation for question 10.
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
Ans. (c) abscisic acid
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
Ans. (b) At the dendritic end electrical impulses bring about the releases of
some chemicals
which generate an electrical impulse at the axonal end of another neuron.
Explanation: Chemicals are released from the axonal end and not from 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
Ans. (c) Medulla in hind brain
Explanation: Medulla is a part of hind brain.
23. Which of the following is not an involuntary action?
(a) Vomiting
(b) Salivation
(c) Heart beat
(d) Chewing
Ans. (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
Ans. (b) differentiate the smell of a perfume from that of an agarbatti
Explanation: When a person is suffering from severe cold, his olfactory
receptors are blocked. Due to this, sense of smell is compromised.
25. What is the correct direction of flow of electrical impulses?
Ans. (c) Explanation: Dendrites of a neuron receive electrical impulse from
axonal end of
another neuron. After that, electrical impulse travels through 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) Thyroid gland requires iodine to synthesise thyroxin
(d) Thyroxin is also called thyroid hormone
Ans. (a) Iron is essential for the synthesis of thyroxin
Explanation: It is iodine which is essential for the synthesis of thyroxin.
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
Ans. (b) Less secretion of growth hormone
Explanation: As the name suggests, growth hormone is responsible for proper
growth in a person. Hence, lack of growth hormone would result in 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
Ans. (c) testosterone from testes and estrogen from ovary
Explanation: These are called sex hormones and are secreted from gonads.
Testosterone is secreted in males and oestrogen is secreted in females.
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 goiter
(d) his sugar level in blood was high
Ans. (d) his sugar level in blood was high
Explanation: if a person is suffering from diabetes then his blood sugar level
may
become high. This disease is managed in some patients by administering insulin
injection.
30. The hormone which increases the fertility in males is called
(a) oestrogen
(b) testosterone
(c) insulin
(d) growth hormone
Ans. (b) Testosterone
31. Which of the following endocrine glands is unpaired?
(a) Adrenal
(b) Testes
(c) Pituitary
(d) Ovary
Ans. (c) Pituitary
32. Junction between two neurons is called
(a) cell junction
(b) neuro muscular junction
(c) neural joint
(d) synapse
Ans. (d) 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
Ans. (d) nervous and endocrine systems
Explanation: Reproductive or respiratory systems have no role to play in control
and coordination.
