Control & Coordination NCERT Exemplar Problems
MCQs Part 3
Question 20: The substance that triggers the fall of mature leaves and fruits from plants is due to
- auxin
- gibberellin
- abscisic acid
- cytokinin
Answer: (c) Abscissic Acid
Question 21: Which of the following statements about transmission of nerve impulse is incorrect?
- Nerve impulse travels from dendritic end towards axonal end
- 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
- 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
- A neuron transmits electrical impulses not only to another neuron but also to muscle and gland cells
Answer: (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
Question 22: Involuntary actions in the body are controlled by
- Medulla in forebrain
- Medulla in midbrain
- Medulla in hindbrain
- Medulla in spinal cord
Answer: (c) Medulla in the hindbrain
Question 23: Which of the following is not an involuntary action?
- Vomiting
- Salivation
- Heart beat
- Chewing
Answer: (d) Chewing
Question 24: When a person is suffering from severe cold, he or she cannot
- Differentiate the taste of an apple from that of an ice cream
- Differentiate the smell of a perfume from that of an agarbatti
- Differentiate red light from green light
- Differentiate a hot object from a cold object
Answer: (b) Differentiate the smell of a perfume from that of an agarbatti
Question 25: What is the correct direction of flow of electrical impulses?
Question 26: Which statement is not true about thyroxin?
- Iron is essential for the synthesis of thyroxin
- It regulates carbohydrates, protein and fat metabolism in the body
- Thyroid gland requires iodine to synthesise thyroxin
- Thyroxin is also called thyroid hormone
Answer: (a) Iron is essential for the synthesis of thyroxine
Question 27: Dwarfism results due to
- Excess secretion of thyroxin
- Less secretion of growth hormone
- Less secretion of adrenaline
- Excess secretion of growth hormone
Answer: (b) Less secretion of growth hormone
Question 28: Dramatic changes of body features associated with puberty are mainly because of secretion of
- Oestrogen from testes and testosterone from ovary
- Oestrogen from adrenal gland and testosterone from pituitary gland
- Testosterone from testes and Oestrogen from ovary
- Testosterone from thyroid gland and Oestrogen from pituitary gland
Answer: Testosterone from testes and Oestrogen from ovary
Question 29: A doctor advised a person to take an injection of insulin because
- His blood pressure was low
- His heart was beating slowly
- He was suffering from goiter
- His sugar level in blood was high
Answer: (d) His sugar level in blood was high
Question 30: The hormone which increases the fertility in males is called
- Oestrogen
- Testosterone
- Insulin
- Growth hormone
Answer: (b) Testosterone
Question 31: Which of the following endocrine glands is unpaired?
- Adrenal
- Testes
- Pituitary
- Ovary
Answer: (c) Pituitary
Question 32: Junction between two neurons is called
- Cell junction
- Neuro muscular junction
- Neural joint
- Synapse
Answer: (d) Synapse
Question 33: In humans, the life processes are controlled and regulated by
- Reproductive and endocrine systems
- Respiratory and nervous systems
- Endocrine and digestive systems
- Nervous and endocrine systems
Answer: (d) Nervous and endocrine systems