Q80. Which element is essential for the thyroid gland to synthesise thyroxine?
[RRB Group D, 18 August 2026, Shift 1 (memory-based paper)]
(A) Iodine
(B) Calcium
(C) Vitamin D
(D) Iron
Answer: (A) Iodine
Explanation: Iodine is incorporated into thyroid hormones T3 and T4. Inadequate iodine intake may reduce thyroid-hormone production and cause goitre. Iodised salt is a major public-health measure against iodine-deficiency disorders. This attribution comes from a memory-based paper rather than an official question booklet.
Q79. Which statements about the pituitary are correct?
(a) It has adenohypophysis and neurohypophysis;
(b) it secretes FSH;
(c) it secretes MSH;
(d) it does not secrete prolactin.
[RE-NEET 2026, Biology]
(A) (b) and (c) only
(B) (a) and (b) only
(C) (a), (b) and (c) only
(D) (c) and (d) only
Answer: (C) (a), (b) and (c) only
Explanation: The pituitary has anterior and posterior divisions. The adenohypophysis synthesises FSH, prolactin and other hormones; the pars intermedia produces MSH, especially in textbook descriptions. Therefore statement (d) is false because prolactin is secreted by anterior-pituitary lactotrophs.
Q78. Match:
(A) excess growth hormone, (B) LH, (C) vasopressin, (D) oxytocin
with (I) kidney water reabsorption, (II) uterine contraction, (III) acromegaly, (IV) ovulation.
[RE-NEET 2026, Biology]
(A) A-IV, B-III, C-I, D-II
(B) A-III, B-IV, C-II, D-I
(C) A-III, B-IV, C-I, D-II
(D) A-II, B-IV, C-I, D-III
Answer: (C) A-III, B-IV, C-I, D-II
Explanation: Excess growth hormone after puberty causes acromegaly. An LH surge triggers ovulation. Vasopressin, or ADH, promotes renal water conservation, while oxytocin stimulates uterine contractions and milk ejection. These four actions belong to different endocrine control pathways.
Q77. Match the hormones: (A) cortisol, (B) aldosterone, (C) cholecystokinin, (D) progesterone
with (I) mammary alveolar development, (II) anti-inflammatory action, (III) renal sodium-water retention, (IV) pancreatic-enzyme and bile secretion.
[NEET 2026, Biology]
(A) A-II, B-III, C-IV, D-I
(B) A-III, B-II, C-I, D-IV
(C) A-IV, B-I, C-II, D-III
(D) A-I, B-IV, C-III, D-II
Answer: (A) A-II, B-III, C-IV, D-I
Explanation: Cortisol is an adrenal glucocorticoid with anti-inflammatory effects. Aldosterone favours sodium retention and indirectly water retention. Intestinal cholecystokinin stimulates pancreatic enzyme secretion and gallbladder contraction. Progesterone participates in mammary gland development and pregnancy support.
Q76. What is the primary function of human growth hormone?
[SSC CHSL Tier I, 28 November 2025, Shift 3]
(A) Controlling only fat digestion
(B) Lowering blood glucose directly
(C) Maintaining body temperature only
(D) Regulating growth and development of the body
Answer: (D) Regulating growth and development of the body
Explanation: Growth hormone, or somatotropin, comes from the anterior pituitary. It promotes tissue growth directly and through insulin-like growth factor 1, chiefly produced in the liver. Deficiency during childhood may impair growth, while excess can cause gigantism or acromegaly.
Q75. Which endocrine organs release hormones associated with puberty in human females?
[SSC CHSL Tier I, 24 November 2025, Shift 1]
(A) Ovaries
(B) Pancreas
(C) Pineal gland
(D) Hypothalamus only
Answer: (A) Ovaries
Explanation: The ovaries produce oestrogens and progesterone, which help regulate female reproductive development and menstrual cycles. The hypothalamus and pituitary help control the ovaries through GnRH, FSH and LH, but the ovaries are the principal gonadal endocrine organs.
Q74. Which organs of the female reproductive system produce sex hormones?
[RRB Group D, 3 December 2025, Shift 2]
(A) Salivary glands
(B) Cervix
(C) Ovaries
(D) Fallopian tubes
Answer: (C) Ovaries
Explanation: The ovaries have both reproductive and endocrine functions. Their follicles produce oestrogens, while the corpus luteum produces substantial progesterone after ovulation. Together these hormones regulate secondary sexual characteristics, the uterine lining and preparation for potential pregnancy.
Q73. Which gland is commonly called the master gland of the human body?
[SSC CGL Tier I, 12 September 2025, Shift 1 (reported paper)]
(A) Thyroid
(B) Adrenal
(C) Pituitary
(D) Pancreas
Answer: (C) Pituitary
Explanation: The pituitary secretes several tropic hormones, including TSH, ACTH, FSH and LH, that regulate other endocrine glands. The title master gland is conventional; the hypothalamus actually directs much pituitary activity through neural and releasing-hormone signals.
Q72. Which hormone released by the pituitary is actually synthesised in the hypothalamus?
[NEET 2025, Biology]
(A) FSH
(B) ACTH
(C) LH
(D) Antidiuretic hormone
Answer: (D) Antidiuretic hormone
Explanation: ADH, also called vasopressin, is produced in hypothalamic nuclei and transported along axons to the posterior pituitary, where it is stored and released. FSH, ACTH and LH are synthesised by endocrine cells in the anterior pituitary.
Q71. Why is ordinary insulin generally not administered by mouth to treat diabetes?
[NEET 2025, Biology]
(A) It is a steroid
(B) Digestion breaks down its peptide structure
(C) It has no receptors
(D) It is only active in the stomach
Answer: (B) Digestion breaks down its peptide structure
Explanation: Insulin is a protein hormone. If swallowed without special protective delivery technology, gastric acid and digestive proteases degrade it, preventing reliable absorption of intact biologically active hormone. Therefore insulin therapy is traditionally given by injection or other non-oral routes.
Q70. Match the sources with hormones: (A) heart, (B) kidney, (C) gastrointestinal tract, (D) adrenal cortex;
(I) erythropoietin, (II) aldosterone, (III) ANF, (IV) secretin.
[NEET 2025, Biology]
(A) A-III, B-I, C-IV, D-II
(B) A-I, B-II, C-IV, D-III
(C) A-II, B-III, C-I, D-IV
(D) A-IV, B-I, C-III, D-II
Answer: (A) A-III, B-I, C-IV, D-II
Explanation: Heart atrial cells release atrial natriuretic factor; kidneys produce erythropoietin, which stimulates red-cell production. The intestine secretes secretin to regulate pancreatic bicarbonate secretion, and adrenal cortical zona glomerulosa cells produce aldosterone for salt balance.
Q69. Diabetes mellitus is most directly associated with dysfunction of which organ?
[UPPSC PCS Preliminary Examination 2024]
(A) Gall bladder
(B) Liver
(C) Kidney
(D) Pancreas
Answer: (D) Pancreas
Explanation: The pancreas contains insulin-producing beta cells that regulate blood glucose. Type 1 diabetes results mainly from beta-cell destruction; type 2 combines insulin resistance and beta-cell dysfunction. Although diabetes affects kidneys and liver, the pancreatic endocrine system is central.
Q68. Hypersecretion of adrenal glucocorticoids is associated with which disorder?
[MHT-CET Biology, 22 April 2024, Morning Shift]
(A) Cushing syndrome
(B) Addison disease
(C) Graves disease
(D) Haemophilia
Answer: (A) Cushing syndrome
Explanation: Prolonged glucocorticoid excess produces Cushing syndrome, characterised by such features as central weight gain, muscle weakness and hyperglycaemia. Addison disease denotes primary adrenal insufficiency. Graves disease causes autoimmune hyperthyroidism; haemophilia is an inherited coagulation disorder.
Q67. What are the islets of Langerhans?
[MHT-CET Biology, 22 April 2024, Morning Shift]
(A) Clusters of endocrine cells in pancreas
(B) Thyroid stromal cells
(C) Star-shaped glial cells
(D) Grey masses in spinal white matter
Answer: (A) Clusters of endocrine cells in pancreas
Explanation: Pancreatic islets contain endocrine beta, alpha and delta cells that release insulin, glucagon and somatostatin into blood. The surrounding acinar pancreas produces digestive enzymes through ducts. The islets therefore explain the organ’s hormone-secreting function.
Q66. Which pair of hormones is NOT generally considered an antagonistic pair?
[MHT-CET Biology, 22 April 2024, Morning Shift]
(A) Calcitonin and parathyroid hormone
(B) Glucagon and insulin
(C) Atrial natriuretic peptide and aldosterone
(D) Oestrogen and progesterone
Answer: (D) Oestrogen and progesterone
Explanation: Calcitonin and PTH exert broadly opposing effects on calcium balance; insulin and glucagon oppose each other in glucose regulation; ANP promotes salt loss while aldosterone promotes salt retention. Oestrogen and progesterone have distinct, often complementary reproductive functions.
Q65. Match (i) oxytocin, (ii) melatonin, (iii) catecholamines, (iv) calcitonin
with (a) adrenal medulla, (b) thyroid, (c) pineal, (d) hypothalamus.
[MHT-CET Biology, 22 April 2024, Evening Shift]
(A) i-a, ii-c, iii-d, iv-b
(B) i-d, ii-a, iii-b, iv-c
(C) i-d, ii-c, iii-a, iv-b
(D) i-c, ii-d, iii-a, iv-b
Answer: (C) i-d, ii-c, iii-a, iv-b
Explanation: Oxytocin is synthesised in the hypothalamus, melatonin in the pineal gland, catecholamines such as adrenaline in the adrenal medulla, and calcitonin in thyroid parafollicular C cells. Distinguishing production from storage or release is especially important for oxytocin.
Q64. Match (i) hCG, (ii) CCK, (iii) ICSH, (iv) MSH
with (a) anterior pituitary, (b) placenta, (c) pars intermedia, (d) intestinal mucosa.
[MHT-CET Biology, 22 April 2024, Evening Shift]
(A) i-b, ii-c, iii-d, iv-a
(B) i-b, ii-d, iii-a, iv-c
(C) i-b, ii-a, iii-d, iv-c
(D) i-d, ii-b, iii-c, iv-a
Answer: (B) i-b, ii-d, iii-a, iv-c
Explanation: Placental trophoblast tissue produces hCG. Intestinal endocrine cells release cholecystokinin, abbreviated CCK. ICSH is another name for LH in males, secreted by the anterior pituitary. Melanocyte-stimulating hormone is associated with the pituitary pars intermedia.
Q63. Match diseases to hormone disturbances: (A) exophthalmic goitre, (B) acromegaly, (C) Cushing syndrome, (D) congenital severe hypothyroidism,
with (I) cortisol excess, (II) thyroid deficiency in development, (III) hyperthyroidism with eye signs, (IV) growth-hormone excess.
[NEET 2024, Biology]
(A) A-III, B-IV, C-I, D-II
(B) A-II, B-III, C-IV, D-I
(C) A-IV, B-I, C-II, D-III
(D) A-I, B-II, C-III, D-IV
Answer: (A) A-III, B-IV, C-I, D-II
Explanation: Graves hyperthyroidism may cause exophthalmos; excessive adult growth hormone causes acromegaly. Cushing syndrome reflects glucocorticoid excess, while severe untreated thyroid-hormone deficiency in early development can impair growth and cognition. These disorders illustrate secretion abnormalities across glands.
Q62. Which pair represents the smallest and largest endocrine glands in humans, respectively, as used in standard general-science examinations?
[WBCS Executive Preliminary Examination 2023]
(A) Pituitary and thyroid
(B) Thyroid and pituitary
(C) Pineal body and ovary
(D) Pineal body and thyroid
Answer: (D) Pineal body and thyroid
Explanation: The pineal gland is a very small structure near the roof of the third ventricle and releases melatonin. The thyroid is the largest purely endocrine gland in adults. The pancreas is larger but is a mixed endocrine–exocrine organ.
Q61. Which single term includes glucocorticoids, mineralocorticoids and adrenaline?
[WBCS Executive Preliminary Examination 2023]
(A) Mineralocorticoids
(B) Adrenaline
(C) Suprarenal gland
(D) Glucocorticoids
Answer: (C) Suprarenal gland
Explanation: Suprarenal is another name for the adrenal gland located above the kidney. Its cortex secretes mineralocorticoids and glucocorticoids; its medulla releases adrenaline and noradrenaline. The listed hormones therefore belong to different regions of the same organ.
Q60. The hormone secretin is produced primarily by which organ?
[WBCS Mains, Science, 2023]
(A) Stomach
(B) Liver
(C) Small intestine
(D) Pancreas
Answer: (C) Small intestine
Explanation: S cells of the duodenal mucosa release secretin in response to acidic chyme. Secretin stimulates bicarbonate-rich pancreatic and biliary secretions that help neutralise acid entering the small intestine, thereby allowing intestinal digestive enzymes to work efficiently.
Q59. Which hormone is secreted by beta cells of the pancreatic islets of Langerhans?
[UPPSC PCS Preliminary Examination, 14 May 2023]
(A) Adrenaline
(B) Glucagon
(C) Insulin
(D) Aldosterone
Answer: (C) Insulin
Explanation: Pancreatic beta cells secrete insulin, which promotes cellular uptake and storage of glucose and lowers blood sugar. Alpha cells secrete glucagon, while delta cells release somatostatin. Dysfunction or destruction of beta cells is central to diabetes mellitus.
Q58. Match the disorders with the correct gland or hormone:
(i) Addison disease, (ii) Hashimoto disease, (iii) acromegaly, (iv) SIADH;
(a) adrenal gland, (b) thyroid gland, (c) growth hormone, (d) vasopressin.
[SSC CGL Tier I, 24 July 2023, Shift 1]
(A) i-b, ii-a, iii-d, iv-c
(B) i-b, ii-c, iii-a, iv-d
(C) i-a, ii-b, iii-c, iv-d
(D) i-d, ii-c, iii-b, iv-a
Answer: (C) i-a, ii-b, iii-c, iv-d
Explanation: Addison disease commonly involves adrenal cortical insufficiency; Hashimoto disease is autoimmune thyroiditis. Acromegaly results from excessive growth hormone after growth plates close. SIADH means inappropriate excess antidiuretic hormone, also called vasopressin, producing water retention.
Q57. Which of the following disease–hormone pairs is incorrectly matched?
[SSC CGL Tier I, 21 July 2023, Shift 4]
(A) Cushing syndrome—cortisol
(B) Diabetes mellitus—insulin
(C) Goitre—thyroxine
(D) Acromegaly—adrenaline
Answer: (D) Acromegaly—adrenaline
Explanation: Acromegaly is caused by excess growth hormone, usually due to a pituitary adenoma, not adrenaline. Cushing syndrome reflects excessive glucocorticoid exposure, and diabetes mellitus involves impaired insulin secretion or action. Goitre means enlarged thyroid, with various possible hormone levels.
Q56. Goitre is a disorder involving which gland?
[SSC MTS Examination, 20 June 2023, Shift 2]
(A) Thyroid gland
(B) Pituitary gland
(C) Pancreas
(D) Adrenal gland
Answer: (A) Thyroid gland
Explanation: Goitre means enlargement of the thyroid, located in the anterior neck. Iodine deficiency is a classic cause, though autoimmune disorders and nodules can also produce it. Thyroid hormone levels may be low, normal or high depending on the cause.
Q55. Which substance is essential for the thyroid gland to manufacture thyroxine?
[UPSC CDS I, General Knowledge, 16 April 2023]
(A) Sodium chloride
(B) Potassium chloride
(C) Cholesterol
(D) Iodine
Answer: (D) Iodine
Explanation: Thyroid follicular cells use dietary iodine and the amino acid tyrosine to make T3 and T4. The names indicate three or four iodine atoms, respectively. Without sufficient iodine, hormone synthesis falls and the thyroid may enlarge under sustained TSH stimulation.
Q54. Which hormone can rapidly increase heartbeat during an emergency?
[UPSC NDA II, General Ability Test, 4 September 2022]
(A) Insulin
(B) Melatonin
(C) Thyroxine
(D) Adrenaline
Answer: (D) Adrenaline
Explanation: Adrenaline is released from the adrenal medulla during sympathetic activation. It raises heart rate and cardiac output, dilates airways and mobilises energy stores. These immediate effects form part of the fight-or-flight response to sudden threat or exertion.
Q53. Which mineral is required for formation of thyroxine?
[RRB Group D, 30 August 2022, Shift 3]
(A) Iron
(B) Calcium
(C) Iodine
(D) Potassium
Answer: (C) Iodine
Explanation: Thyroxine is tetraiodothyronine, abbreviated T4, and contains four iodine atoms. The thyroid requires dietary iodine to synthesise its hormones. Iodine deficiency is associated with thyroid enlargement and potentially impaired physical and neurological development during early life.
Q52. Which of the following is NOT a ductless endocrine gland?
[RRB Group D, 29 August 2022, Shift 1]
(A) Pituitary gland
(B) Salivary gland
(C) Adrenal gland
(D) Thyroid gland
Answer: (B) Salivary gland
Explanation: Salivary glands are exocrine: their secretions enter the mouth through ducts. The pituitary, adrenal and thyroid glands are endocrine and release hormones into the blood. An organ such as the pancreas contains both endocrine and exocrine tissue.
Q51. Which hormone helps the body respond immediately when a person is angry, frightened or worried?
[RRB Group D, 28 September 2022, Shift 2]
(A) Adrenaline
(B) Thyroxine
(C) Oestrogen
(D) Testosterone
Answer: (A) Adrenaline
Explanation: Adrenaline, or epinephrine, is a catecholamine released rapidly by adrenal medullary cells. It prepares the body for action by increasing heart rate, opening airways and directing more blood to active muscles. Cortisol supports a slower, longer-lasting stress response.
Q50. Which mineral is needed for the synthesis of the hormone thyroxine?
[SSC MTS, 11 July 2022, Shift 3]
(A) Iron
(B) Cobalt
(C) Calcium
(D) Iodine
Answer: (D) Iodine
Explanation: Thyroid hormones are iodinated molecules derived from tyrosine. Iodine deficiency impairs their synthesis, sometimes producing hypothyroidism and goitre. Using iodised salt is a preventive strategy; iron and calcium are important nutrients but cannot replace iodine in thyroxine.
Q49. An endocrinologist specialises in the study and treatment of disorders of which body system?
[WBCS Mains, Science, 2022]
(A) Teeth
(B) Hormone-secreting glands
(C) Epidemics
(D) Heart
Answer: (B) Hormone-secreting glands
Explanation: Endocrinology concerns hormones, the glands that produce them, and their effects. Specialists diagnose disorders of thyroid function, diabetes, adrenal disease, pituitary problems and reproductive hormones. Endocrine signalling differs from the duct-based secretion of exocrine glands.
Q48. Which of these is an endocrine gland in the human body?
[RRB NTPC CBT I, 26 July 2021, Shift 1]
(A) Salivary
(B) Pituitary
(C) Prostate
(D) Sweat
Answer: (B) Pituitary
Explanation: The pituitary releases hormones into the circulation rather than through a duct. Its anterior lobe produces growth and tropic hormones, whereas its posterior lobe releases hypothalamic oxytocin and vasopressin. Salivary and sweat glands are typical exocrine examples.
Q47. Which gland hangs from the hypothalamus by a stalk and is traditionally called the master gland?
[RRB NTPC CBT I, 16 January 2021, Shift 2]
(A) Pancreas
(B) Thyroid
(C) Adrenal
(D) Pituitary
Answer: (D) Pituitary
Explanation: The pituitary lies below the hypothalamus in the sella turcica of the sphenoid bone. Its stalk, the infundibulum, provides neural and vascular connections. Several anterior pituitary hormones regulate thyroid, adrenal and gonadal endocrine activity.
Q46. Human growth hormone is secreted mainly by which region?
[RRB NTPC CBT I, 19 January 2021, Shift 1]
(A) Posterior pituitary
(B) Anterior pituitary
(C) Thyroid
(D) Pancreas
Answer: (B) Anterior pituitary
Explanation: Somatotroph cells in the anterior pituitary produce growth hormone. It promotes skeletal and soft-tissue growth partly through IGF-1. The posterior pituitary stores and releases oxytocin and vasopressin but does not synthesise growth hormone.
Q45. Undersecretion of growth hormone during childhood is classically associated with dysfunction of which gland?
[RRB NTPC CBT I, 18 January 2021, Shift 2]
(A) Thyroid
(B) Pituitary
(C) Adrenal medulla
(D) Pancreas
Answer: (B) Pituitary
Explanation: Pituitary growth-hormone deficiency during childhood can cause proportionate short stature, sometimes termed pituitary dwarfism in older textbooks. Height depends on many other influences, including genetics, nutrition and thyroid hormones, so not every case of short stature is endocrine.
Q44. Which glands secrete hormones important in the control of blood pressure?
[RRB NTPC CBT I, 19 March 2021, Shift 2]
(A) Adrenal glands
(B) Pituitary glands only
(C) Pancreas only
(D) Pineal gland
Answer: (A) Adrenal glands
Explanation: The adrenal cortex secretes aldosterone, which promotes renal sodium retention and influences blood volume and pressure. The adrenal medulla releases catecholamines, which affect cardiovascular activity. Blood pressure also depends on kidneys, vessels and nervous-system regulation.
Q43. Which hormone promotes strong uterine contractions during childbirth?
[RRB NTPC CBT I, 27 February 2021, Shift 1]
(A) ADH
(B) Oxytocin
(C) Progesterone
(D) Thyroxine
Answer: (B) Oxytocin
Explanation: Oxytocin is synthesised in the hypothalamus and released through the posterior pituitary. During labour, cervical stretch encourages further oxytocin release, strengthening uterine contractions. The hormone also causes milk ejection, whereas prolactin drives milk production.
Q42. Which hormone from a gland in the brain helps regulate the sleep–wake cycle?
[SSC CHSL, 5 August 2021, Shift 1]
(A) Oxytocin
(B) Insulin
(C) Aldosterone
(D) Melatonin
Answer: (D) Melatonin
Explanation: Melatonin is secreted mainly by the pineal gland, with higher output in darkness. Light suppresses its secretion via circadian pathways. Melatonin helps signal biological night and coordinates timing, but sleep itself is controlled by several interacting neural systems.
Q41. Which of the following hormones is produced by the pancreas?
[BPSC 66th Preliminary Examination, 2020]
(A) Thyroxine
(B) Insulin
(C) Melatonin
(D) Gastrin
Answer: (B) Insulin
Explanation: Insulin is produced by beta cells in the pancreatic islets of Langerhans. It reduces blood glucose by promoting cellular uptake and storage of nutrients. The pancreas also produces glucagon and digestive enzymes, so it functions as a mixed gland.
Q40. Which of these is a principal female sex hormone?
[BPSC 66th Preliminary Examination, 2020]
(A) Oestrogen
(B) Androgen
(C) Insulin
(D) Oxytocin
Answer: (A) Oestrogen
Explanation: Oestrogens are primarily produced by ovarian follicles and support reproductive-organ development, secondary sexual characteristics and regulation of the menstrual cycle. Other listed hormones have different principal roles, although both sexes naturally produce some oestrogens and androgens.
Q39. Deficiency or ineffective action of insulin is associated with which disorder?
[SSC CHSL, 12 October 2020, Shift 1]
(A) Scleroderma
(B) Multiple sclerosis
(C) Rheumatoid arthritis
(D) Diabetes mellitus
Answer: (D) Diabetes mellitus
Explanation: Diabetes mellitus is characterised by chronic hyperglycaemia arising from insufficient insulin secretion, impaired insulin action, or both. Type 1 diabetes usually involves autoimmune beta-cell destruction, whereas type 2 commonly combines insulin resistance with progressive secretory dysfunction.
Q38. Which human organ functions as both an endocrine and an exocrine gland?
[UPPSC PCS Preliminary Examination 2019]
(A) Adrenal gland
(B) Lacrimal gland
(C) Pancreas
(D) Thyroid gland
Answer: (C) Pancreas
Explanation: Pancreatic islets release insulin, glucagon and other hormones directly into blood. Separately, acinar cells produce digestive enzymes that travel through ducts to the small intestine. This dual secretory role explains why the pancreas is called a mixed gland.
Q37. Which cells secrete androgen hormones in human males?
[MPPSC State Service Preliminary Examination 2019]
(A) Sertoli cells
(B) Leydig cells
(C) Germinal cells
(D) Mucus cells
Answer: (B) Leydig cells
Explanation: Leydig cells lie between the seminiferous tubules in the testes and secrete testosterone under luteinising-hormone stimulation. Sertoli cells support sperm development and release inhibin B. Testosterone contributes to male reproductive function and secondary sexual characteristics.
Q36. Which hormone contains iodine as a constituent of its molecule?
[BPSC 65th Preliminary Examination 2019]
(A) Testosterone
(B) Adrenaline
(C) Thyroxine
(D) Insulin
Answer: (C) Thyroxine
Explanation: Thyroxine, also called T4, is formed by iodination of tyrosine residues in thyroglobulin. Its molecule contains four iodine atoms. Insulin is a peptide hormone, testosterone is a steroid, and adrenaline is a catecholamine without iodine.
Q35. Choose the odd one out: hormone, insulin, thyroxine, adrenaline.
[SSC CHSL, 9 July 2019, Shift 1]
(A) Hormone
(B) Insulin
(C) Thyroxine
(D) Adrenaline
Answer: (A) Hormone
Explanation: Insulin, thyroxine and adrenaline are individual hormones with identifiable glandular origins and actions. Hormone is the general class containing all three. Insulin lowers blood glucose; thyroxine controls metabolism; adrenaline mediates rapid stress responses.
Q34. Which was the first human hormone produced commercially through recombinant DNA technology?
[RPSC Senior Teacher Grade II Science, 1 July 2017]
(A) Insulin
(B) Oestrogen
(C) Thyroxine
(D) Progesterone
Answer: (A) Insulin
Explanation: Recombinant human insulin was an early major application of genetic engineering and was approved for therapeutic use in 1982. Genetically modified microorganisms can manufacture human insulin, avoiding reliance on extraction from animal pancreases and reducing some compatibility concerns.
Q33. What is the hormone secreted by the thymus gland called?
[SSC CGL, 10 August 2017, Shift 2]
(A) Thyroxine
(B) Auxin
(C) Cytokinin
(D) Thymosin
Answer: (D) Thymosin
Explanation: The thymus supports the development and selection of T lymphocytes involved in immune defence. Thymic hormones, including thymosin-related peptides, help regulate lymphocyte maturation. The gland is prominent during childhood and undergoes involution after puberty.
Q32. Insulin belongs to which broad class of chemical messengers?
[SSC CGL, 10 August 2017, Shift 3]
(A) Hormones
(B) Digestive enzymes
(C) Vitamins
(D) Mineral salts
Answer: (A) Hormones
Explanation: Insulin is a peptide hormone secreted by pancreatic beta cells. It carries information from the pancreas to target tissues through the blood, facilitating glucose storage and utilisation. Although it is also chemically a protein, its physiological role is hormonal.
Q31. Which of the following are major ovarian sex hormones: (i) oestrogen, (ii) progesterone, (iii) testosterone?
[SSC CGL, 12 August 2017, Shift 3]
(A) (i) and (iii) only
(B) (i) and (ii) only
(C) (ii) and (iii) only
(D) (iii) only
Answer: (B) (i) and (ii) only
Explanation: Oestrogen and progesterone are the two principal ovarian hormones emphasised in school-level biology. They regulate female secondary sexual characteristics, menstrual changes and support for pregnancy. Testosterone is also present in females, but is primarily classified as an androgen.
Q30. Adrenaline is best classified as which of the following?
[SSC CGL, 16 August 2017, Shift 3]
(A) Hormone
(B) Digestive enzyme
(C) Vitamin
(D) Storage fat
Answer: (A) Hormone
Explanation: Adrenaline is a catecholamine hormone released into the blood by adrenal medullary chromaffin cells. It is also used as a neurotransmitter in some contexts. Its systemic action increases heart activity, airway dilation and glucose availability during emergencies.
Q29. Which of the following is NOT a plant hormone?
[SSC CGL, 10 August 2017, Shift 1]
(A) Gibberellin
(B) Auxin
(C) Cytokinin
(D) Thyroxine
Answer: (D) Thyroxine
Explanation: Thyroxine is an animal thyroid hormone that regulates metabolism and development. Auxins, cytokinins and gibberellins are plant growth regulators involved in processes such as cell elongation, cell division, stem growth and seed germination.
Q28. Which hormone–function pair is incorrectly matched?
[UPPSC PCS Preliminary Examination 2017]
(A) Insulin—blood-glucose regulation
(B) Melatonin—sleep timing
(C) Oxytocin—milk ejection
(D) Gastrin—blood-pressure regulation
Answer: (D) Gastrin—blood-pressure regulation
Explanation: Gastrin is secreted chiefly by G cells of the gastric antrum and stimulates stomach acid secretion. It is not primarily a blood-pressure regulator. Insulin acts in glucose homeostasis, melatonin in circadian timing, and oxytocin in milk let-down.
Q27. Insulin influences metabolism of which of the following nutrients?
[BPSC 63rd Preliminary Examination 2017]
(A) Fats only
(B) Carbohydrates only
(C) Proteins only
(D) Carbohydrates, fats and proteins
Answer: (D) Carbohydrates, fats and proteins
Explanation: Insulin regulates much more than blood glucose. It promotes glycogen synthesis, fat storage and protein synthesis while inhibiting several catabolic pathways. Thus carbohydrates, lipids and proteins all respond to insulin signalling, especially after a meal.
Q26. Insulin is chemically classified as a type of what?
[BPSC 60th–62nd Preliminary Examination 2016]
(A) Fat
(B) Vitamin
(C) Carbohydrate
(D) Protein
Answer: (D) Protein
Explanation: Human insulin is a peptide hormone consisting of two chains with a total of 51 amino acids linked by disulphide bonds. It is therefore a protein in biochemical classification and lowers blood glucose through receptor-mediated effects.
Q25. Which hormone is used as an emergency treatment for a severe allergic reaction with a dangerous fall in blood pressure?
[RPSC Senior Teacher Grade II Science Examination 2015]
(A) Insulin
(B) Adrenaline
(C) Thyroxine
(D) Melatonin
Answer: (B) Adrenaline
Explanation: Adrenaline rapidly supports blood pressure, reduces airway swelling and relaxes bronchial smooth muscle during anaphylaxis. It is first-line emergency treatment for that condition. The original examination described a marked fall in blood pressure more generally; clinical treatment depends on its cause.
Q24. Iodine is essential for the synthesis of which hormone?
[RPSC Senior Teacher Grade II Science Examination 2015]
(A) Adrenaline
(B) Insulin
(C) Thyroxine
(D) Testosterone
Answer: (C) Thyroxine
Explanation: The thyroid incorporates iodine into thyroxine and triiodothyronine. The other options are an adrenal catecholamine, a pancreatic peptide, and a steroid androgen. Dietary iodine deficiency can lead to reduced thyroid-hormone synthesis and thyroid enlargement.
Q23. Insulin is best described chemically as a:
[UPPSC PCS Mains Examination 2015]
(A) Steroid
(B) Carbohydrate
(C) Protein
(D) Fat
Answer: (C) Protein
Explanation: Insulin contains amino-acid chains, making it a peptide or protein hormone. It binds cell-surface receptors and affects carbohydrate, lipid and protein metabolism. It is not a steroid, which is a cholesterol-derived hormone class.
Q22. Which of the following is a plant hormone?
[CGPSC Preliminary Examination 2014 (held 7 June 2015)]
(A) Insulin
(B) Thyroxine
(C) Oestrogen
(D) Cytokinin
Answer: (D) Cytokinin
Explanation: Cytokinins are plant growth regulators that stimulate cell division and influence shoot development and leaf ageing. Insulin, thyroxine and oestrogen are animal hormones. The recruitment-exam cycle was labelled 2014, although its paper was administered in 2015.
Q21. Which hormone naturally exists as a gas under ordinary conditions?
[CGPSC Preliminary Examination 2013 (held 8 June 2014)]
(A) Abscisic acid
(B) Ethylene
(C) Gibberellin
(D) Auxin
Answer: (B) Ethylene
Explanation: Ethylene is a gaseous plant hormone associated with fruit ripening, senescence and responses to stress. The remaining options are other classes of plant growth regulators but are not normally gaseous. This is a plant-hormone comparison rather than a human endocrine-gland question.
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.
Q10. Which hormone primarily regulates the calcium and phosphate balance of human blood?
[UPSC Civil Services Preliminary Examination 2007]
(A) Glucagon
(B) Growth hormone
(C) Parathyroid hormone
(D) Thyroxine
Answer: (C) Parathyroid hormone
Explanation: Parathyroid hormone increases blood calcium by acting on bone and kidneys and by promoting active vitamin D formation. It also reduces renal phosphate reabsorption, increasing phosphate excretion. Its secretion is governed mainly by circulating ionised calcium.
Q9. Which plant hormone is most associated with senescence and fruit ripening?
[WBCS Preliminary Examination 2007]
(A) Cytokinin
(B) Auxin
(C) Gibberellin
(D) Ethylene
Answer: (D) Ethylene
Explanation: Ethylene is a gaseous plant growth regulator that can accelerate ripening and senescence. Cytokinins tend to delay leaf senescence, auxins commonly support cell elongation and gibberellins promote stem growth and seed germination. This is included as a comparative hormone PYQ.
Q8. What is a principal cardiovascular function of noradrenaline?
[WBCS Preliminary Examination 2005]
(A) Increase blood pressure
(B) Increase urine formation
(C) Increase cellular respiration only
(D) Release adrenaline from the thyroid
Answer: (A) Increase blood pressure
Explanation: Noradrenaline, or norepinephrine, activates adrenergic receptors, particularly alpha receptors in blood vessels, causing vasoconstriction and often raising blood pressure. It functions both as a sympathetic neurotransmitter and as a hormone released by the adrenal medulla.
Q7. Match endocrine organs with hormones:
(A) gonads, (B) pituitary, (C) pancreas, (D) adrenal;
(1) insulin, (2) progesterone, (3) growth hormone, (4) cortisol.
[Chhattisgarh PSC Preliminary Examination 2005]
(A) A-3, B-2, C-4, D-1
(B) A-2, B-3, C-4, D-1
(C) A-2, B-3, C-1, D-4
(D) A-3, B-2, C-1, D-4
Answer: (C) A-2, B-3, C-1, D-4
Explanation: Gonadal tissue produces sex hormones including progesterone; the anterior pituitary secretes growth hormone; pancreatic beta cells release insulin; and the adrenal cortex produces cortisol. Remembering the anatomical source prevents confusion between adrenal cortex and medulla.
Q6. The human hormone insulin is produced principally in which organ?
[Uttar Pradesh Lower Subordinate Preliminary Examination 2004]
(A) Liver
(B) Pancreas
(C) Kidney
(D) Pituitary
Answer: (B) Pancreas
Explanation: Islets of Langerhans in the pancreas contain beta cells that manufacture insulin. When blood glucose rises, these cells increase insulin secretion to aid utilisation and storage of nutrients. The organ also makes glucagon and exocrine digestive enzymes.
Q5. What is thyroxine?
[UPPSC PCS Preliminary Examination 2003]
(A) Vitamin
(B) Hormone
(C) Digestive enzyme
(D) Antibody
Answer: (B) Hormone
Explanation: Thyroxine is a thyroid hormone also called T4 because it contains four iodine atoms. It is converted in many tissues to the more active T3 and plays major roles in metabolic rate, development and temperature regulation.
Q4. Which pancreatic structures produce insulin?
[Uttarakhand UDA/LDA Preliminary Examination 2003]
(A) Islets of Langerhans
(B) Pituitary follicles
(C) Thyroid follicles
(D) Adrenal cortex
Answer: (A) Islets of Langerhans
Explanation: Insulin is produced by beta cells within the pancreatic islets of Langerhans. Other pancreatic islet cell types release glucagon and somatostatin. The islets are endocrine tissue, unlike the nearby digestive-enzyme-producing acinar cells.
Q3. Which hormone is associated with affectionate contact between a mother and infant and helps milk let-down?
[Uttar Pradesh Lower PCS Preliminary Examination 2003]
(A) Insulin
(B) Noradrenaline
(C) Follicle-stimulating hormone
(D) Oxytocin
Answer: (D) Oxytocin
Explanation: Infant suckling stimulates neural pathways that release oxytocin from the posterior pituitary. Oxytocin contracts mammary myoepithelial cells and causes milk ejection. It is also involved in social bonding, although behaviour reflects complex brain processes beyond one hormone.
Q2. Consider:
(1) exercise can increase somatotropin secretion;
(2) testes can produce small amounts of progesterone;
(3) female adrenal glands can contribute to androgen production;
(4) stress reduces cortisol secretion.
Which statements are correct?
[UPSC Civil Services Preliminary Examination 2002]
(A) 1, 2, 3 and 4
(B) 1, 2 and 3 only
(C) 2, 3 and 4 only
(D) 1 and 4 only
Answer: (B) 1, 2 and 3 only
Explanation: Exercise can stimulate growth-hormone release; testes produce small amounts of progesterone, and adrenal glands in females contribute androgen precursors. Stress generally increases, rather than decreases, cortisol through the hypothalamic–pituitary–adrenal axis, so statement four is false.
Q1. Which one of the following is NOT an endocrine gland?
[WBCS Preliminary Examination 2002]
(A) Adrenal cortex
(B) Pituitary
(C) Salivary gland
(D) Thyroid
Answer: (C) Salivary gland
Explanation: Salivary glands pour saliva through ducts into the mouth and are therefore exocrine. Adrenal cortex, pituitary and thyroid release hormones into blood without excretory ducts. The distinguishing feature of an endocrine gland is its route of hormone secretion.