All Free Biology MCQs with Answers

• A. Troponin
• B. Tropomyosin
• C. Myosin
• D. Actinin

Explanation: Myosin is a contractile protein that interacts with actin to bring about contraction of muscle or cell movement.

• A. Tropomyosin
• B. Tubulin
• C. Myosin
• D. All of these

Explanation: Myosin is a contractile protein of muscle. Primary myofilaments are made up of this protein.

• A. Smooth muscles
• B. Skeletal muscles
• C. Cardiac muscles
• D. Both A and C

Explanation: Cardiac muscles are myogenic in nature, because the heartbeat is initiated by the SA node and the impulse of contraction originates in the…

• A. Sarcolemma
• B. Sarcoplamic reticulum
• C. Sarcomere
• D. Myofilament

Explanation: The sarcolemma is the term used to describe the specialized cell membrane that surrounds each individual muscle fiber (also known as a…

• A. Bone
• B. Joints
• C. Muscle fiber
• D. Glial cells

Explanation: The sarcolemma is the specialized cell membrane that surrounds each individual muscle fiber, also known as a muscle cell or myofiber.

• A. Part between two H zones
• B. Part between two A bands
• C. Part between two I bands
• D. Part between two Z lines

Explanation: The sarcomere is the fundamental unit of a striated muscle fiber, delineated by two Z lines.

• A. A band becomes short
• B. | band elongates
• C. There is no change in sarcomere
• D. Z- lines get close

Explanation: Option D is correct since the sarcomere shortens during muscle contraction. A sarcomere is a structure bound by two consecutive Z lines.

• A. Glycosidic bond
• B. Hydrogen bond
• C. Peptide bond
• D. Disulfide bond

Explanation: The correct answer is the glycosidic bond. This bond is a covalent linkage specifically formed between two monosaccharides, resulting in…

• A. 1
• B. 3
• C. 4
• D. 5

Explanation: In the Calvin cycle, six molecules of Glyceraldehyde 3-phosphate (G3P) are produced.

• A. DNA and histone protein
• B. RNA and histone protein
• C. Nitrogenous base and sugar.
• D. Niitrogenous base, sugar and phosphate

Explanation: A nucleosome is composed of DNA and histone proteins, forming the basic unit of DNA packaging in eukaryotic cells.

• A. 3
• B. 6
• C. 9
• D. 12

Explanation: The correct answer is Option C: 9. The water-soluble vitamins include the B-complex vitamins and Vitamin C.

• A. RER-Golgi apparatus-Secretory vesicles
• B. SER-RER-Golgi apparatus-Secretory vesicles
• C. RER-SER-Golgi apparatus-Secretory vesicles
• D. RER-Golgi apparatus-Secretory vesicles-SER

Explanation: The correct answer is C: RER-SER-Golgi apparatus-Secretory vesicles. This sequence accurately represents the pathway of secretory…

• A. Outer anal sphincter
• B. Both outer and inner anal sphiniters
• C. Inner and sphiniter
• D. Connot be inhibited

Explanation: The majority of protein digestion occurs in the duodenum, the first segment of the small intestine.

• A. Adhesion
• B. Cohesion
• C. Capillary action
• D. Transpiration

Explanation: This is the correct answer. Adhesion refers to the attraction between molecules of different substances.

• A. Fatty acids
• B. Ribulose
• C. Ascorbic acid
• D. Deoxyribonucleic acid
• E. Ribonucleic acid

Explanation: RNA (ribonucleic acid) is a type of nucleic acid that is involved in the process of protein synthesis.

• A. Cell-mediated response
• B. Humoral immune response
• C. Active immunity
• D. Passive immunity

Explanation: T lymphocytes recognize an antigen and then attack microorganisms and the connection to it.

• A. B lymphocytes
• B. Helper T lymphocytes
• C. Cytotoxic T lymphocytes
• D. Memory cells
• E. Macrophages

Explanation: Explanation for this question will be added soon.

• A. Male
• B. Female
• C. AIDS patient
• D. Athletes

Explanation: Aspergillosis occurs in humans, birds, and other animals. Aspergillosis occurs in chronic or acute forms which are clinically very…

• A. Measles
• B. Influenza
• C. Hepatitis A
• D. AIDS

Explanation: a. Measles: Measles weakens the immune system, making individuals more susceptible to opportunistic infections.

• A. It is a retrovirus
• B. It is surrounded by an envelope
• C. It does not cause AIDS
• D. It causes deficiency of the human immune system

Explanation: It is a well known fact that HIV virus does cause AIDS.