All Free Biology MCQs with Answers

• A. Enlargement of bones
• B. Slow heart rate and nervousness
• C. Loss of body weight
• D. Sexual precocity

Explanation: Hyperthyroidism happens when the thyroid gland makes too much thyroid hormone. This condition also is called overactive thyroid.

• A. Adrenal cortex
• B. Adrenal medulla
• C. Cerebral cortex
• D. Cerebral medulla

Explanation: Cortisone is the man-made form of the natural hormone cortisol. Cortisol is a steroid hormone that is produced by the adrenal glands…

• A. Sodium in water
• B. Calcium in water
• C. Iodine in water
• D. Sugar in water

Explanation: Goiter is caused by an iodine deficiency, which is vital for the production of thyroid hormones.

• A. Thyroxine
• B. Non_adrenaline
• C. Adrenaline
• D. All of above

Explanation: Thyroxine: Thyroxine was the first hormone to be isolated and crystallized in 1914, making it a significant milestone in endocrinology.

• A. Thyroxine
• B. Nor adrenalin
• C. Adrenalin
• D. All of the above

Explanation: Thyroxine, also known as T4, is the first hormone to be identified as a crystalline substance.

• A. Protein hormones
• B. Non-steroid hormones
• C. Steroid hormones
• D. Peptide hormones

Explanation: Steroid hormones are synthesized from cholesterol and include key hormones such as testosterone, estrogen, cortisol, and aldosterone.

• A. PTH (Parathyroid Hormone)
• B. Thyroxine
• C. Aldosterone
• D. Calcitonin

Explanation: Thyroxine is the hormone secreted by the thyroid gland that plays a key role in regulating the body's metabolism.

• A. Testes and ovaries
• B. Adrenal glands and gonads
• C. Adrenal cortex and gonads
• D. Gonads and thyroids

Explanation: Steroid hormones are primarily produced by the adrenal cortex and the gonads.

• A. Alpha-cells
• B. Beta-cells
• C. Delta-cells
• D. Gamma-cells

Explanation: Insulin is produced by Beta cells, which are found in the islets of Langerhans in the pancreas.

• A. Pituitary gland
• B. Adrenal gland
• C. Parathyroid
• D. Thyroid

Explanation: The pituitary gland, specifically through the release of antidiuretic hormone (ADH), plays a crucial role in managing the body's water…

• A. MSH
• B. LH
• C. ADH
• D. Melatonin

Explanation: Melatonin is a hormone involved in many biological and physiological regulations in the body.

• A. LH (Luteinizing Hormone)
• B. ACTH (Adrenocorticotropic Hormone)
• C. FSH (Follicle-Stimulating Hormone)
• D. ADH (Antidiuretic Hormone)

Explanation: Antidiuretic hormone (ADH) is a chemical produced in the brain that causes the kidneys to release less water, decreasing the amount of…

• A. Hyperthyroidism
• B. Hypocalcemia
• C. Hypochondria
• D. Hypercalcemia

Explanation: Exophthalmia, the abnormal protrusion of the eyes, is typically associated with Graves' disease, a form of hyperthyroidism.

• A. Parathormone (PTH)
• B. Calcitonin
• C. Thyroxine
• D. Both (a) & (b)

Explanation: The release of calcium from bone into the blood is controlled by parathyroid hormone (PTH).

• A. Cortisol
• B. Testosterone
• C. Insulin
• D. Aldosterone

Explanation: Insulin is a non-steroidal hormone, distinct from steroid hormones which are derived from cholesterol and are fat-soluble.

• A. Stretching of uterus
• B. Stretching of Cervix
• C. Low level of testosterone
• D. Low level of progesterone

Explanation: The correct answer is Option C: Low level of testosterone. Testosterone is a male sex hormone and does not influence the release of…

• A. Thyroid gland-T3 and T4
• B. Parathyroid gland-Calcitonin
• C. Pancreas-Insulin
• D. Gonads-Testes and ovaries

Explanation: The correct answer is Option B: 'Parathyroid gland-Calcitonin'. This is a mismatch because the parathyroid glands produce parathyroid…

• A. Thymus
• B. Pituitary
• C. Thyroid
• D. Pancreas

Explanation: The pancreas serves as both an endocrine and an exocrine gland. As an endocrine gland, it produces hormones like insulin and glucagon…

• A. Pancreas
• B. Gonads
• C. Adrenal gland
• D. Both (A) & (B)

Explanation: The gland that serves as both an exocrine and endocrine gland is the pancreas.

• A. Insulin
• B. Prolactin
• C. Lactogen
• D. Thyroxine

Explanation: Prolactin is the hormone responsible for milk secretion after parturition (childbirth).