Chemical Coordination and Integration Mock Test – Class 11 Biology

1. Thyroid tissue is separated into two viable fractions. Fraction P is enriched in follicular cells surrounding small cavities, while fraction Q contains mainly stromal tissue. When adequate iodine is supplied, and synthesis occurs mainly in P. The strongest inference is:

2. During a stressful condition, adrenal-medullary secretion remains normal but cortisol action on its target cells is selectively blocked. Which outcome is most likely?

3. Order the events in an ANF-mediated response to elevated blood pressure correctly.
P. Blood vessels dilate.
Q. Increased pressure stimulates atrial-wall cells.
R. Blood pressure falls toward its previous level.
S. Atrial natriuretic factor is released.

4. A person with diabetes mellitus has inadequate insulin secretion. Regular insulin administration lowers persistent hyperglycaemia and improves glucose uptake by responsive tissues. The treatment is effective mainly because it:

5. Choose the sequence that correctly orders the events in the action pathway of vasopressin.
P. Water loss through urine decreases.
Q. Vasopressin is synthesised in hypothalamic neurosecretory cells.
R. Reabsorption by distal renal tubules increases.
S. The hormone is transported to and released from pars nervosa.

6. An action potential in a hypothalamic neurosecretory cell triggers release of ADH from pars nervosa. ADH then travels through the blood and acts on receptor-bearing distal renal tubules. This pathway best demonstrates that:

7. Four renal profiles are recorded after separate hormone treatments.

The profile most consistent with aldosterone action is:

8. Testosterone concentration remains normal, but androgen responsiveness is selectively lost in the epididymis, vas deferens, seminal vesicles and prostate. The most likely consequence is:

9. Which statements accurately describe testicular endocrine tissue?
I. Leydig cells occur in the spaces between seminiferous tubules.
II. These cells secrete androgens, mainly testosterone.
III. Seminiferous tubules are described as the principal androgen-secreting cells.
IV. Testosterone is classified as an estrogen.

10. A thyroid nodule begins synthesising and secreting abnormally large quantities of and , despite adequate dietary iodine. The resulting endocrine state is most likely:

11. A hormone enters its target cell, binds a nuclear receptor and alters gene expression. When transcription is experimentally blocked, new protein production and the physiological response decline. The strongest conclusion is:

12. Assertion: The modern definition of a hormone restricts the term to secretions of organised glands that travel only to distant organs.
Reason: Hormone-producing cells may occur in tissues that are not organised as classical endocrine glands.

13. Judge the statements related to pituitary regulation in the male.
I. LH stimulates testicular synthesis and secretion of androgens.
II. FSH acts together with androgens in regulating spermatogenesis.
III. FSH alone is sufficient for normal spermatogenesis even when androgens are absent.
IV. LH and FSH are collectively called gonadotrophins.

14. Analyse the statements describing the adrenal glands.
I. One adrenal gland lies above each kidney.
II. The adrenal cortex occupies the central region.
III. The adrenal medulla is surrounded by the cortex.
IV. The adrenal glands are paired endocrine organs.

15. Determine which statements apply to growth hormone.
I. It promotes growth and development of somatic tissues.
II. Excess secretion during the growing period can produce gigantism.
III. Deficient secretion during growth can cause pituitary dwarfism.
IV. Excess secretion in an adult characteristically produces gigantism.

16. Use the arrangement described below. Region P sends hormonal signals to the thyroid, adrenal cortex and gonads. Region Q stores and releases two hormones synthesised in hypothalamic neurons. Which comparison is correct?

17. Use the arrangement described below. A thyroid lobe is viewed from its posterior surface. Two small endocrine bodies are attached to that lobe, and an equivalent pair occurs on the posterior surface of the opposite lobe. These bodies are:

18. Comparable thyroid-hormone deficiency occurs in two situations. In Case P it affects a fetus during maternal hypothyroidism; in Case Q it develops in a non-pregnant adult. Which distinction is most appropriate?

19. Assertion: Destruction of TSH-secreting pituitary cells can reduce thyroid-hormone output even when the thyroid gland itself is structurally intact.
Reason: TSH normally stimulates the synthesis and secretion of thyroid hormones.

20. Match each thymus-related feature with its appropriate description. A Column II entry is used once.

21. A person with prolonged dietary iodine deficiency has persistently strong TSH stimulation of the thyroid. Which outcome remains most likely as long as iodine is not restored?

22. A coordinating signal must regulate cells that may lack direct nerve supply and must support effects lasting beyond a brief nerve impulse. The most suitable signal is:

23. Assertion: Degeneration of the thymus in old age generally strengthens immune responses.
Reason: Reduced thymosin production can weaken T-lymphocyte differentiation and antibody production.

24. The pineal secretion most directly associated with regulation of diurnal rhythms is:

25. Four gastrointestinal-hormone treatments produce the following observations.

The profile most consistent with GIP action is:

26. Which set contains only major organised endocrine bodies rather than hormone-producing tissues embedded in multifunctional organs?

27. Identical blood-vessel preparations are exposed to fluid containing either ANF or no added hormone. The ANF-treated vessels widen, while the control vessels show little change. Which conclusion is most strongly supported?

28. Select the biologically valid sequence for the events in a gastrin-dependent pathway.
P. Hydrochloric acid and pepsinogen secretion increases.
Q. Gastrin is released from gastrointestinal endocrine cells.
R. Gastrin reaches responsive gastric glands.
S. Gastric secretory activity is stimulated.

29. Four metabolic profiles are recorded after separate pancreatic-hormone treatments.

The profile most consistent with insulin action is:

30. During an operation, the pair of parathyroid glands on the posterior surface of one thyroid lobe is removed. The other thyroid lobe retains its normal parathyroid pair, and thyroid follicular tissue remains functional. Which immediate interpretation is best supported?

31. A functional receptor for hormone H is introduced into a previously non-responsive cell. The cell’s downstream signalling machinery is intact. After exposure to H, the most likely outcome is:

32. A pair of organs lies in the scrotal sacs outside the abdominal cavity. It produces male gametes and also releases hormones into the circulation. This organ is correctly classified as:

33. Blood pressure remains elevated despite a large increase in ANF secretion. Laboratory testing shows that atrial cells release normal ANF, but vascular target cells lack functional ANF receptors. Which interpretation is most appropriate?

34. Two reproductive target-cell preparations are treated as follows.

Which immediate comparison is most defensible?

35. Match each pars-distalis hormone with its principal target or effect. A Column II entry is used once.

36. Which classification is internally consistent?

37. Trace the events in the pathway initiated by thyroid-stimulating hormone in its proper sequence.
P. Thyroid hormones are synthesised and secreted.
Q. TSH is released from pars distalis.
R. TSH reaches and stimulates the thyroid gland.

38. Two individuals have persistently elevated growth-hormone secretion. Case P develops excessive general body growth while still in the active growing period. Case Q develops progressive enlargement of facial features after major body growth is complete. The appropriate diagnosis is:

39. Assess the statements given for exophthalmic goitre or Graves’ disease.
I. The thyroid gland is enlarged.
II. The eyeballs may protrude.
III. Basal metabolic rate is increased.
IV. Progressive weight gain is a characteristic result of the elevated metabolic state.

40. Melatonin secretion retains its normal daily rhythm. Receptors for melatonin are selectively lost in target cells regulating sleep-wake and body-temperature cycles, while melatonin-responsive cells involved in pigmentation, menstrual cycling and defence remain functional. Which pattern is most likely?

41. Which disorder profile is completely consistent?

42. During thyroid surgery, all four parathyroid glands are accidentally removed, but most thyroid follicular tissue remains functional. Which postoperative pattern is most likely?

43. Assertion: Aldosterone lowers body-fluid volume by increasing renal loss of and water.
Reason: Aldosterone promotes renal reabsorption of and water while increasing excretion of and phosphate.

44. Isolated thyroid tissue is divided into two identical preparations. Preparation P receives TSH, while preparation Q receives no pituitary hormone. P shows a marked rise in thyroid-hormone synthesis and secretion. The result supports the conclusion that:

45. A lobular endocrine gland is located between the lungs, behind the sternum and ventral to the aorta. This gland is the:

46. Normal synthesis of and depends on adequate dietary ______; prolonged deficiency may produce ______ with thyroid enlargement.

47. An individual from an iodine-deficient region develops an enlarged thyroid gland together with reduced thyroid-hormone production. Which diagnosis best fits the findings?

48. A graph plots relative body-fluid volume against time after aldosterone administration. The curve rises gradually and then stabilises. Renal measurements taken during the rising phase show increased and water reabsorption. The trend is best explained by:

49. Two individuals have reduced red-blood-cell formation. Case P has damaged erythropoietin-producing kidney cells, while Case Q has normal renal secretion but blood-forming tissue that cannot respond to erythropoietin. The common outcome occurs because:

50. A microscopic thyroid lesion selectively destroys the cells forming the wall of each follicle, while much of the stromal tissue and the follicular cavities remain visible. Which effect is most directly expected?