All Free Biology MCQs with Answers

• A. Energy source of the cell
• B. Coenzyme
• C. Cofactor
• D. Both Options A and B are correct

Explanation: ATP (adenosine triphosphate) is a molecule that serves as the primary energy source for most cellular processes.

• A. 90
• B. 20
• C. 10
• D. 1
• E. None of these

Explanation: Explanation for this question will be added soon.

• A. Enzymes are mostly proteins but some are lipids also
• B. Enzymes are denatured at high temperatures
• C. Enzymes are highly specific
• D. Enzymes require optimum pH and temperature for maximum activity

Explanation: Option A: Enzymes are mostly proteins but some are lipids also: This statement is incorrect.

• A. 1010
• B. 2010
• C. 1020
• D. 1510

Explanation: Yes, enzymes can speed up reactions by factors of up to 1010 (ten billion) or even higher.

• A. The primary structure of enzymes
• B. The secondary structure of enzymes
• C. Tertiary structure of enzymes
• D. Quarternary structure of enzymes

Explanation: Tertiary structure of enzymes. Enzyme-substrate specificity arises from the unique three-dimensional shape of the enzyme's active site…

• A. Apoenzyme
• B. Holoenzyme
• C. Activated enzyme
• D. Both B and C

Explanation: Correct option is B. The answer is holoenzyme. An enzyme is a protein that catalyzes a chemical reaction.

• A. Thyrotropin
• B. Corticotropin
• C. Somatotropin
• D. Prolactin

Explanation: Gigantism occurs when a child's pituitary gland makes too much growth hormone, which is also known as somatotropin.

• A. Thyroid stimulating hormone
• B. LH
• C. ACTH
• D. FSH
• E. ADH

Explanation: Explanation for this question will be added soon.

• A. FSH
• B. Calcitonin
• C. Parathyroid hormone
• D. ADH
• E. Insulin

Explanation: Explanation for this question will be added soon.

• A. Labor pains
• B. Body temperature
• C. Insulin production
• D. Thyroxin release

Explanation: Labor pains are an example of a physiological process controlled through positive feedback, where the response reinforces and amplifies…

• A. Ovaries
• B. Hypothalamus
• C. Pituitary
• D. Testes

Explanation: Gonadotropins are released by the pituitary gland. Examples include LH, FSH etc.

• A. Body temperature
• B. Glucagon production
• C. Labor contraction
• D. Parathyroid activity

Explanation: Oxytocin stimulates the muscle contractions that push the baby through the birth canal.

• A. Growth Hormone - Somatostatin
• B. Calcitonin - Parathyroid
• C. Adrenaline - Noradrenaline
• D. Insulin - Glucagon

Explanation: A is incorrect because somatostatin inhibits the release of growth hormone from the pituitary gland.

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

Explanation: The pituitary gland is sometimes called the "master" gland of the endocrine system because it controls the functions of many of the other…

• A. Cortisone
• B. Adrenaline
• C. Insulin
• D. Thyroxin

Explanation: The steroids that are made almost exclusively in the adrenal glands are cortisol, 11-deoxycortisol, aldosterone, corticosterone, and…

• A. ADH (Antidiuretic Hormone)
• B. Oxytocin
• C. Glucagon
• D. Thyroxin

Explanation: ADH is released in response to increased blood osmolality or decreased water content.

• A. Mg2+
• B. Na+
• C. K+
• D. Ca2+

Explanation: Parathyroid glands play a crucial role in regulating calcium levels in the blood.

• A. Centrioles
• B. Asters
• C. Spindles
• D. Cleavage furrows

Explanation: Centrioles are not present in plant cells. Mitotic spindles are microtubule based structures that separate chromosomes during mitosis.

• A. 25
• B. 50
• C. 100
• D. 125

Explanation: 100 wheat grains will develop from 100 zygotes.100 zygotes mean 100 pollen and 100 eggs are required.

• A. Two chromatids
• B. Two chromosomes
• C. Six chromatids
• D. Four chromosomes

Explanation: The term bivalent refers to a specific structure that forms during meiosis, the process of cell division that produces gametes (sex…