Class 11 Biology MCQ – Chemical Control and Coordination

1. Which gland is often referred to as the "master gland"?

a) Thyroid gland
b) Adrenal gland
c) Pancreas
d) Pituitary gland

Answer:

d) Pituitary gland

Explanation:

The pituitary gland is often called the "master gland" because it regulates many other glands in the endocrine system.

2. Which hormone helps plants in their response to light?

a) Auxin
b) Gibberellin
c) Abscisic acid
d) Cytokinin

Answer:

a) Auxin

Explanation:

Auxins play a crucial role in phototropism, the growth of a plant in response to light.

3. What is the primary function of insulin?

a) Increase blood sugar levels
b) Stimulate appetite
c) Reduce blood sugar levels
d) Stimulate gastric juice secretion

Answer:

c) Reduce blood sugar levels

Explanation:

Insulin is secreted by the pancreas and helps in the uptake of glucose by cells, thereby reducing blood sugar levels.

4. The "fight or flight" response is triggered by which hormone?

a) Oxytocin
b) Estrogen
c) Adrenaline
d) Prolactin

Answer:

c) Adrenaline

Explanation:

Adrenaline prepares the body to respond to a threat, often referred to as the "fight or flight" response.

5. Which gland is responsible for regulating the body's circadian rhythm?

a) Pineal gland
b) Parathyroid gland
c) Thymus gland
d) Salivary gland

Answer:

a) Pineal gland

Explanation:

The pineal gland secretes melatonin, which regulates the body's sleep-wake cycle or circadian rhythm.

6. Which of the following hormones is produced by the ovaries?

a) Testosterone
b) Insulin
c) Estrogen
d) Thyroxine

Answer:

c) Estrogen

Explanation:

Estrogen is a female sex hormone produced by the ovaries.

7. Which hormone promotes water retention in the body?

a) Glucagon
b) Aldosterone
c) Antidiuretic hormone (ADH)
d) Serotonin

Answer:

c) Antidiuretic hormone (ADH)

Explanation:

ADH or vasopressin acts on the kidneys to promote water retention, thus reducing urine volume.

8. The deficiency of which hormone can cause goiter?

a) Thyroxine
b) Insulin
c) Cortisol
d) Progesterone

Answer:

a) Thyroxine

Explanation:

Goiter is an enlargement of the thyroid gland, often due to a deficiency of thyroxine or iodine deficiency.

9. Which gland diminishes in size as a person ages?

a) Thyroid gland
b) Thymus gland
c) Adrenal gland
d) Pancreas

Answer:

b) Thymus gland

Explanation:

The thymus gland, involved in immune response, is most active during childhood and diminishes in size with age.

10. The hormone responsible for increasing calcium levels in the blood is:

a) Calcitonin
b) Parathyroid hormone (PTH)
c) Insulin
d) Gastrin

Answer:

b) Parathyroid hormone (PTH)

Explanation:

PTH is responsible for increasing calcium levels in the blood by promoting the release of calcium from bones.

11. Which hormone stimulates uterine contractions during childbirth?

a) Oxytocin
b) Progesterone
c) Adrenaline
d) Somatostatin

Answer:

a) Oxytocin

Explanation:

Oxytocin is released in response to stretching of the cervix and uterus and causes uterine contractions during childbirth.

12. The secretion of which hormone would increase during a prolonged fast?

a) Insulin
b) Glucagon
c) Thyroxine
d) Aldosterone

Answer:

b) Glucagon

Explanation:

Glucagon increases the concentration of glucose in the bloodstream, which would be beneficial during a prolonged fast.

13. Which of the following is NOT an endocrine gland?

a) Pituitary gland
b) Sweat gland
c) Thyroid gland
d) Adrenal gland

Answer:

b) Sweat gland

Explanation:

Sweat glands are exocrine glands that release sweat through ducts onto the skin's surface.

14. Which hormone plays a role in regulating the body's metabolism?

a) Cortisol
b) Thyroxine
c) Progesterone
d) Prolactin

Answer:

b) Thyroxine

Explanation:

Thyroxine, produced by the thyroid gland, plays a crucial role in regulating the body's metabolism.

15. Which hormone is involved in the body's response to stress?

a) Melatonin
b) Thyroxine
c) Cortisol
d) Calcitonin

Answer:

c) Cortisol

Explanation:

Cortisol is released by the adrenal glands in response to stress and helps in increasing blood sugar, among other functions.

16. Which hormone is responsible for the secondary sexual characteristics in males?

a) Testosterone
b) Estrogen
c) Prolactin
d) Oxytocin

Answer:

a) Testosterone

Explanation:

Testosterone, produced by the testes, is responsible for the development of secondary sexual characteristics in males.

17. The hormone responsible for lowering blood glucose levels is:

a) Insulin
b) Glucagon
c) Adrenaline
d) Somatostatin

Answer:

a) Insulin

Explanation:

Insulin promotes the uptake of glucose by cells, which results in a decrease in blood glucose levels.

18. The hormone that promotes the development of T cells is:

a) Insulin
b) Thymosin
c) Thyroxine
d) Serotonin

Answer:

b) Thymosin

Explanation:

Thymosin, produced by the thymus gland, is responsible for the differentiation of T cells, which are essential for the immune response.

19. Which hormone is responsible for the milk let-down reflex in nursing mothers?

a) Prolactin
b) Oxytocin
c) Estrogen
d) Progesterone

Answer:

b) Oxytocin

Explanation:

Oxytocin causes milk ejection or the "let-down" reflex in lactating mothers.

20. Which of the following hormones helps in regulating the sleep-wake cycle?

a) Melatonin
b) Adrenaline
c) Cortisol
d) Gastrin

Answer:

a) Melatonin

Explanation:

Melatonin, produced by the pineal gland, plays a key role in regulating the circadian rhythm or sleep-wake cycle.

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