Q20. Assertion: Bright light during sleep is undesirable.
Reason: Bright light considerably increases melatonin production.
Choose the correct option.
[UPPSC Review Officer/Assistant Review Officer Preliminary Examination 2014]
(A) Both are true and reason explains assertion
(B) Both true but reason does not explain
(C) Assertion true, reason false
(D) Assertion false, reason true
Answer: (C) Assertion true, reason false
Explanation: Melatonin production increases in darkness and is suppressed by light, particularly light reaching the retina at night. Thus the assertion is sensible for circadian regulation, but the reason reverses the actual light–melatonin relationship.
Q19. Why is iodised salt useful in preventing certain endocrine disorders?
[Jharkhand PSC Preliminary Examination 2013]
(A) It supplies insulin
(B) It replaces thyroid hormone directly
(C) It supplies iodine needed by the thyroid
(D) It stimulates adrenal cortisol
Answer: (C) It supplies iodine needed by the thyroid
Explanation: Iodised salt supplies iodine, a raw material for thyroid-hormone synthesis. Without adequate intake, T3 and T4 production may decline and the gland may enlarge. Iodised salt is preventive; it does not directly contain replacement thyroid hormone.
Q18. Assertion: Iodine-deficiency goitre has historically been common in certain mountainous regions.
Reason: The local diet may provide insufficient iodine.
Which is correct?
[Uttarakhand PCS Preliminary Examination 2012]
(A) Both true and reason explains assertion
(B) Both true but unrelated
(C) Assertion true, reason false
(D) Assertion false, reason true
Answer: (A) Both true and reason explains assertion
Explanation: Iodine-depleted soil and food chains can reduce dietary intake, particularly in some inland and hilly areas. Low thyroid-hormone synthesis raises pituitary TSH, which can enlarge the thyroid. Universal salt iodisation reduces this preventable cause of goitre.
Q17. Deficiency of antidiuretic hormone is associated with which disorder?
[WBCS Preliminary Examination 2012]
(A) Diabetes insipidus
(B) Diabetes mellitus
(C) Graves disease
(D) Cushing disease
Answer: (A) Diabetes insipidus
Explanation: ADH deficiency causes central diabetes insipidus, characterised by excretion of large quantities of dilute urine and excessive thirst. It differs from diabetes mellitus, which involves glucose regulation. Nephrogenic diabetes insipidus instead reflects poor kidney response to ADH.
Q16. Hypothyroidism is primarily characterised by which hormonal change?
[RPSC Nursing Tutor Examination 2011]
(A) Decreased thyroid hormones
(B) Increased thyroid hormones
(C) Increased growth hormone
(D) Increased adrenaline
Answer: (A) Decreased thyroid hormones
Explanation: Hypothyroidism means insufficient thyroid-hormone activity. In primary thyroid failure, circulating free T4 is often low and TSH elevated. Typical manifestations include fatigue, cold intolerance and slowed metabolism, though diagnosis relies on appropriate hormone tests.
Q15. Insulin belongs to which chemical category?
[Jharkhand PSC Preliminary Examination 2010]
(A) Glycolipid
(B) Fatty acid
(C) Peptide
(D) Sterol
Answer: (C) Peptide
Explanation: Insulin is a peptide hormone made of amino-acid chains, secreted by pancreatic beta cells. It acts through a membrane receptor with tyrosine-kinase activity. Sterols and fatty acids belong to different chemical classes and cannot describe its structure.
Q14. Which hormone most directly controls the amount of water lost in urine?
[Uttar Pradesh UDA/LDA Special Mains Examination 2010]
(A) TSH
(B) ACTH
(C) FSH
(D) ADH
Answer: (D) ADH
Explanation: Antidiuretic hormone, or vasopressin, increases water reabsorption by the kidney collecting ducts via aquaporin-2 insertion. Consequently, urine becomes more concentrated and its volume falls. Deficiency can cause central diabetes insipidus with unusually large volumes of dilute urine.
Q13. Match hormones with organs:
(A) progesterone, (B) testosterone, (C) thyroxine, (D) insulin;
(1) thyroid, (2) pancreas, (3) ovary, (4) testes.
[Uttar Pradesh UDA/LDA Preliminary Examination 2010]
(A) A-3, B-4, C-1, D-2
(B) A-4, B-3, C-1, D-2
(C) A-3, B-4, C-2, D-1
(D) A-1, B-2, C-3, D-4
Answer: (A) A-3, B-4, C-1, D-2
Explanation: Progesterone is secreted by ovarian corpus luteum tissue, testosterone mainly by Leydig cells in testes, thyroxine by thyroid follicles, and insulin by pancreatic beta cells. The pairing tests both endocrine anatomy and the principal hormone produced by each organ.
Q12. A surge of which hormone normally triggers ovulation in a human female?
[MPPSC State Service Preliminary Examination 2009]
(A) Luteinising hormone
(B) Oestrogen
(C) Follicle-stimulating hormone
(D) Progesterone
Answer: (A) Luteinising hormone
Explanation: A mid-cycle surge of luteinising hormone causes rupture of the mature ovarian follicle and release of the oocyte. FSH supports follicular development, while rising oestrogen before ovulation helps trigger the LH surge through positive feedback.
Q11. From which gland is the milk-ejection hormone oxytocin released?
[Rajasthan Administrative Services Preliminary Examination 2007]
(A) Posterior pituitary
(B) Thyroid gland
(C) Parathyroid gland
(D) Adrenal gland
Answer: (A) Posterior pituitary
Explanation: Oxytocin is synthesised by neurons in the hypothalamus and carried to the posterior pituitary for storage and release. It stimulates contraction of myoepithelial cells around mammary alveoli, forcing milk outward. Prolactin, by contrast, stimulates milk synthesis.
