Chemical Coordination and Integration Mock Test – Class 11 Biology

1. Review the endocrine pathways below.

The row requiring correction is:

2. Hormone receptors in target cells are best classified as:

3. Judge the statements related to hormones acting through membrane-bound receptors.
I. The receptor is located in the plasma membrane.
II. The hormone generally remains outside the target cell.
III. Receptor activation can generate an intracellular second messenger.
IV. The extracellular hormone itself must directly bind the target-cell genome.

4. Two individuals show increased heartbeat and respiratory activity.
Case P develops the changes within seconds of a sudden threat, along with pupil dilation and increased alertness.
Case Q shows a persistent increase in basal metabolic rate, weight loss, thyroid enlargement and protruding eyeballs.
Which interpretation is correct?

5. A target cell continues to receive a steroid hormone, but its intracellular receptor is selectively destroyed. Membrane receptors and general metabolic enzymes remain functional. The most likely result is:

6. Two substances are isolated from human tissues. Substance P is produced in large quantity and used directly as a metabolic nutrient. Substance Q is released in trace amount from specialised atrial-wall cells, travels through blood and alters distant receptor-bearing cells. Under the modern endocrine definition:

7. Assertion: Opposing hormonal effects can stabilise a regulated physiological variable.
Reason: Insulin lowers blood glucose while glucagon raises it, and PTH raises blood calcium while thyrocalcitonin lowers it.

8. 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?

9. A hypothalamic factor normally suppresses secretion of hormone X from the anterior pituitary. If delivery of this factor to the anterior pituitary is selectively blocked while the pituitary cells remain functional, the most likely immediate change is:

10. Pancreatic -cells are selectively destroyed in an experimental animal. Over time, blood glucose remains elevated, glucose appears in urine and ketone bodies increase. Which conclusion is best supported?

11. Identical renal-tubule preparations are maintained under the same conditions. Preparation P receives aldosterone, while Q does not. P shows greater and water reabsorption and greater and phosphate excretion. The result supports the conclusion that aldosterone:

12. Pituitary cells that secrete prolactin are selectively damaged, while posterior-pituitary release remains intact. Which change is expected most directly?

13. Use the ovarian arrangement described below. Structure P is a developing follicle, Q is a mature Graafian follicle, R represents release of the ovum, and S is the corpus luteum formed afterward. Which hormonal relation best fits the sequence?

14. A target cell produces the normal number of receptors for hormone H, but a mutation changes the hormone-binding region of each receptor. All downstream signalling components remain functional. The most likely result is:

15. 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:

16. The following profiles are observed after altered pineal activity.

Which profiles fall within the known influence of melatonin?

17. A non-pregnant adult female has persistently reduced thyroid activity, while pituitary growth-hormone secretion remains normal. A likely reproductive consequence is:

18. Hypothalamic synthesis and axonal transport of ADH and oxytocin remain normal, but exocytotic release from neuronal endings in pars nervosa is selectively blocked. Which pattern is most likely?

19. A pituitary preparation releases MSH and can release axonally supplied oxytocin and vasopressin, but it produces no GH, PRL, TSH, ACTH, LH or FSH. Which regional interpretation best fits the pattern?

20. Two comparable groups receive identical diets. Group P is given thyroid hormones, while Group Q receives no thyroid-hormone treatment. P shows coordinated changes in carbohydrate, protein and fat metabolism that are absent in Q. The strongest supported conclusion is:

21. Equal liver-cell preparations contain comparable glycogen stores. Preparation P receives glucagon, while Q receives no pancreatic hormone. P shows greater glycogen breakdown and releases more glucose into the surrounding medium. The strongest inference is:

22. The table lists four hormone-producing sources and their structural settings.

Which conclusion is supported by all four entries?

23. A protein hormone is secreted by the thyroid gland and acts to lower blood concentration. The hormone is:

24. Examine the following claims about receptor location.
I. Some hormone receptors occur in the plasma membrane.
II. Some receptors occur within the cytoplasm or nucleus.
III. Every hormone receptor is exposed on the external cell surface.
IV. Many intracellular receptors are located in the nucleus.

25. A peptide hormone is added separately to hepatocytes and adipocytes. Both cell types increase glucose uptake and utilisation, and liver cells also increase glycogen formation. The hormone is:

26. Select the valid statements concerning cortisol.
I. It is the principal glucocorticoid in humans.
II. It contributes to maintenance of cardiovascular and kidney functions.
III. It stimulates red-blood-cell production.
IV. It promotes inflammation and strengthens immune responses.

27. Determine the proper order for the events in a pituitary-thyroid pathway.
P. and are synthesised and secreted.
Q. TSH is released from pars distalis.
R. Thyroid follicular cells are stimulated.
S. Metabolic and developmental processes are regulated.

28. A steroid hormone enters a target cell and forms its normal intracellular receptor complex. A treatment prevents the complex from interacting with the genome. Messenger RNA and protein responses are greatly reduced. The strongest inference is:

29. Identify the correct progression of the events in an insulin-mediated response after blood glucose rises.
P. Glucose uptake and utilisation by target cells increase.
Q. Pancreatic -cells secrete insulin.
R. Blood-glucose concentration falls toward its previous level.
S. Glycogenesis increases in responsive cells.

30. Identical experimental animals are divided into two groups. Group P receives thyrocalcitonin, while Group Q receives no hormone. Blood falls in P but remains near its initial level in Q. The strongest inference is:

31. An individual has prolonged hyperglycaemia despite adequate food intake. Tests indicate insufficient insulin action, and glucose uptake by target tissues is reduced. The most appropriate diagnosis is:

32. 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:

33. Identify the valid statements about progesterone.
I. The corpus luteum is its principal ovarian source after ovulation.
II. It supports the maintenance of pregnancy.
III. It promotes formation of mammary alveoli and milk secretion.
IV. It is the principal hormone causing milk ejection through mammary contraction.

34. During a catecholamine surge, hepatic glycogenolysis is selectively blocked while the heart and respiratory system remain responsive. Which outcome is most likely?

35. Analyse the statements describing erythropoietin.
I. It is secreted by juxtaglomerular cells of the kidney.
II. It is a peptide hormone.
III. It stimulates erythropoiesis.
IV. It is released from the atrial wall to dilate blood vessels.

36. Receptors for a required growth factor are selectively blocked in an injured tissue, while the factor continues to be produced normally. The most likely result is:

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

38. Identify the correct progression of the stages in a genome-linked steroid-hormone response.
P. New proteins contribute to a physiological response.
Q. The hormone enters the target cell.
R. Messenger RNA production changes.
S. A hormone-receptor complex forms inside the cell.
T. The complex interacts with the genome.

39. Review the statements concerning diabetes mellitus.
I. Prolonged hyperglycaemia is a central feature.
II. Glucose may be lost through urine.
III. Harmful ketone bodies may form when normal glucose utilisation is impaired.
IV. The disorder is produced primarily by excessive ADH action on renal tubules.

40. 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?

41. Assertion: A hormone can alter target-cell metabolism without entering the cell.
Reason: Binding to a membrane receptor can generate an intracellular second messenger that initiates biochemical changes.

42. Aldosterone secretion and ANF secretion both increase. Which interpretation of their simultaneous cardiovascular contributions is most accurate?

43. Assertion: FSH and estrogen can both promote reproductive-tissue growth through different receptor mechanisms.
Reason: FSH is secreted by pars distalis, while estrogens are produced mainly by growing ovarian follicles.

44. Three endocrine sequences are represented below.
P. GnRH anterior pituitary gonadotrophins gonads
Q. TSH thyroid gland iodothyronines
R. ACTH adrenal cortex glucocorticoids
Which common relationship is demonstrated by all three?

45. PTH secretion rises normally, but its action on renal tubular reabsorption is selectively blocked. Bone and intestinal responses remain functional. Which outcome is most likely?

46. A graph plots melatonin secretion on the vertical axis against clock time over three days. The total daily secretion remains approximately the same, but the nightly peak occurs several hours later on days two and three. A person's sleep period remains at its original time. Which inference is most defensible?

47. Dietary iodine is adequate and circulating TSH is present, but thyroid follicular cells lack functional TSH receptors. Which pattern is most likely?

48. Arrange the events initiated by gonadotrophin-releasing hormone in the correct order.
P. Gonadal activity is stimulated.
Q. Gonadotrophins are synthesised and released.
R. GnRH is secreted by hypothalamic neurosecretory cells.
S. GnRH acts on the anterior pituitary.

49. Which option gives the correct order of the stages through which a hormone produces a response in a receptor-bearing target cell?
P. Target-cell metabolism or physiological activity changes.
Q. The hormone reaches the target cell.
R. A hormone-receptor complex forms.
S. Receptor activation initiates biochemical changes.

50. Hormone H binds normally to its receptor, and the expected second messenger rises inside the target cell. A downstream metabolic enzyme remains inactive, so the usual response is absent. Direct activation of that enzyme restores the response without changing hormone binding. The strongest inference is: