Biology MCQs with Answer (part 3) by General knowledge Solutions

Biology MCQs with Answer (part 3) by General knowledge Solutions

                                                                               

1. Binding of catecholamines to α2− adrenergic receptors

(A) Increases the intracellular concentration of cAMP

(B) Increases the intracellular concentration of cGMP

(C) Decreases the intracellular concentration of cAMP

(D) Decreases the intracellular concentration of cGMP

2. Phosphoinositide cascade is activated on binding of catecholamines to

(A) α1-Adrenergic receptors

(B) α2-Adrenergic receptors

(C) β1-Adrenergic receptors

(D) β2-Adrenergic receptors

3. Epinephrine decreases

(A) Glycogenesis

(B) Glycogenolysis

(C) Gluconeogenesis

(D) Lipolysis

4. Epinephrine increases the concentration of free fatty acids in plasma by increasing

(A) Extramitochondrial fatty acid synthesis

(B) Mitochondrial fatty acid chain elongation

(C) Microsomal fatty acid chain elongation

(D) Lipolysis in adipose tissue

5. Epinephrine increases all of the following except

(A) Glycogenolysis in muscles

(B) Lipolysis in adipose tissue

(C) Gluconeogenesis in muscles

(D) Glucagon secretion

6. Secretion of catecholamines is increased in

(A) Cushing’s syndrome

(B) Addison’s disease

(C) Phaeochromocytoma

(D) Simmond’s disease

 7. Zona glomerulosa of adrenal cortex synthesises

(A) Glucocorticoids

(B) Mineralocorticoids

(C) Androgens

(D) Estrogen and progesterone

8. Cortisol is a

(A) Glucocorticoid

(B) Mineralocorticoid

(C) Androgen

(D) Estrogen

9. The major mineralcorticoid is

(A) Hydrocortisone

(B) Aldosterone

(C) Aldactone A

(D) Androstenedione

10. Steroid hormones are synthesised in all of the following except

(A) Testes

(B) Ovaries

(C) Adrenal medulla

(D) Adrenal cortex

11. Steroid hormones are synthesised from

(A) Cholesterol

(B) 7-Dehydrocholesterol

(C) Calcitriol

(D) 7-Hydroxycholesterol

12. A common intermediate in the synthesis of all the steroid hormones is

(A) Pregnenolone

(B) 17-Hydroxypregnenolone

(C) Corticosterone

(D) Progesterone

13. A common intermediate in the synthesis of cortisol and aldosterone is

(A) Progesterone

(B) Testosterone

(C) Estradiol

(D) None of these

14. A common intermediate in the synthesis of estrogens is

(A) Cortisol

(B) Andostenedione

(C) Corticosterone

(D) 11-Deoxycorticosterone

15. Glucocorticoids are transported in blood

(A) In association with transcortin chiefly

(B) In association with albumin to some extent

(C) In free form partly

(D) All of these

16. All the following statements about transcortin are true except

(A) It is synthesised in liver

(B) It transports glucocorticoids

(C) It transports aldosterone

(D) It transports progesterone

17. The second messenger for glucocorticoids is

(A) Cyclic AMP

(B) Cyclic GMP

(C) Inositol triphosphate

(D) No second messenger is required

18. Glucocorticoids increase all of the following except

(A) Gluconeogenesis

(B) Lipolysis in extremities

(C) Synthesis of elcosanoida

(D) Hepatic glycogenesis

19. Glucocorticoids increase the synthesis of all of the following except

(A) Glucokinase

(B) Glucose-6-phosphatase

(C) Fructose-1, 6-biphosphatase

 (D) Pyruvate carboxylase

20. Secretion of glucocorticoida is regulated by all the following except

(A) Hypothalamus

(B) Anterior pituitary

(C) Feedback control by blood glucose

(D) Feedback control by glucocorticoids

21. Excessive secretion of glucocorticoids raises blood glucose by

(A) Decreasing glycogenesis

(B) Increasing glycogenolysis

(C) Increasing gluconeogenesis

(D) Inhibiting HMP shunt

22. Mineralcorticoids regulate the metabolism of all of the following except

(A) Sodium

 (B) Potassium

(C) Calcium

(D) Chloride

23. Mineralocorticoids increase the tubular reabsorption of

(A) Sodium and calcium

(B) Sodium and potassium

(C) Sodium and chloride

(D) Potassium and chloride

24. Mineralocorticoids increase the tubular secretion of

(A) Sodium

(B) Potassium

(C) Chloride

(D) Bicarbonate

25. Secretion of mineralcorticoids is increased by

(A) ACTH

(B) Angiotensin

(C) Hypokalaemia

(D) Hypernatraemia

26. In Addison’s disease, there is excessive retention of

(A) Potassium

(B) Sodium

(C) Chloride

(D) Water

27. In adrenogenital syndrome due to total absence of 21-hydroxylase in adrenal cortex, there is

(A) Deficient secretion of glucocorticoids

(B) Deficient secretion of mineralcorticoids

(C) Excessive secretion of androgens

(D) All of these

28. Spironolactone is an antagonist of

 (A) Cortisol

(B) Hydrocortisone

(C) Aldosterone

(D) Testosterone

29. Androgens are synthesised in

(A) Leydig cells in testes

(B) Sertoli cells in testes

(C) Seminiferous tubules

(D) Prostate gland

30. Testosterone is transported in blood by

(A) Transcortin

 (B) Testosterone binding globulin

(C) Testosterone estrogen binding globulin

(D) Albumin

31. The metabolites of androgens are

(A) 17-Hydroxysteroids

(B) 17-Ketosteroids

(C) 11-Hydroxysteroids

(D) 11-Ketosteroids

32. An androgen which is more powerful than testosterone is

(A) Androstenedione

(B) Dihydrotestosterone

(C) Androsterone

(D) Epiandrosterone

33. Secretion of androgens is increased by

(A) LH

(B) FSH

(C) ACTH

(D) Growth hormone

34. During late pregnancy, the major source of progesterone is

(A) Adrenal cortex

(B) Placenta

(C) Corpus luteum

(D) Graafian follicles

35. Progesterone is transported in blood by

(A) Transcortin

(B) Sex hormone binding globulin

(C) Albumin

(D) Testosterone estrogen binding globulin

36. The major metabolite of progesterone is

(A) Pregnenolone

(B) Pregnanediol

(C) Estradiol

(D) Norethindrone

37. Secretion of progesterone

(A) Is more in first half of menstrual cycle than in second half

(B) Is more in second half of menstrual cycle than in first half

(C) Remains constant during menstrual cycle

(D) Decreases during pregnancy

38. Women become susceptible to osteoporosis after menopause due to decreased

(A) Secretion of Parathormone

(B) Conversion of vitamin D into calcitriol

(C) Secretion of estrogen

(D) Secretion of progesterone

39. A hormone used for detection of pregnancy is

(A) Estrogen

(B) Progesterone

(C) Oxytocin

(D) Chorionic gonadotropin

40. Placenta secretes all of the following except

(A) FSH

(B) Progesterone

(C) Estrogen

(D) Chorionic gonadotropin

41. Gastrin is a polypeptide made up of

(A) Five amino acids

(B) Twelve amino acids

(C) Seventeen amino acids

(D) Twenty amino acids

42. Biological activity of gastrin is present in the

(A) Four N-terminal amino acids

(B) Four C-terminal amino acids

(C) Five N-terminal amino acids

(D) Five C-terminal amino acids

43. All the following statements about β- endorphin are true except µ :

(A) It is a polypeptide

(B) Its precursor is pro-opio-melanocortin

(C) Its receptors are represent in brain

(D) Its action is blocked by morphine

44. All the following statements about epidermal growth factor are true except

(A) It is a protein

(B) It possess quaternary structure

(C) Its receptor is made up of a single polypeptide chain

(D) Its receptor possesses tyrosine kinase domain

45. Met-enkephalin is a

(A) Tripeptide

(B) Pentapeptide

(C) Octapeptide

(D) Decapeptide

46. Vasoconstrictor effect of ADH is mediated by

(A) cAMP

(B) cGMP

(C) Protein kinase C

(D) Angiotensin II

47. The rate limiting step in catecholamine synthesis is catalysed by

(A) Phenylalanine hydroxylase

(B) Tyrosine hydroxylase

(C) Dopa decarboxylase

(D) Phenylethanolamine N-methyl transferase

48. Dopa decarboxylase is inhibited by

(A) Epinephrine

(B) Norepinephrine

(C) α−Methyldopa

(D) None of these

Answer

1. C 2. A 3. A 4. D 5. C 6. C 7. A 8. B 9. C 10. A 11. A 12. A 13. A 14. B 15. D 16. C 17. D 18. C 19. A 20. C 21. C 22. C 23. C 24. B 25. B 26. A 27. D 28. C 29. A 30. C 31. B 32. B 33. A 34. B 35. A 36. B 37. B 38. C 39. D 40. A 41. C 42. B 43. D 44. B 45. B 46. C 47. B 48. C