All Free Biology MCQs with Answers

• A. Spontaneous stimuli
• B. Nervous stimuli
• C. Stretch stimuli
• D. Hormonal stimuli

Explanation: Cardiac muscles are myogenic and the stimulus is generated by the SA node spontaneously.

• A. To pump blood
• B. To move the skeleton
• C. To control the movement of substances through hollow organs
• D. To pump the lymph

Explanation: The cardiac muscle is responsible for the contractility of the heart and, therefore, the pumping action.

• A. To pump blood
• B. To move the skeleton
• C. To control the movement of substances through hollow organs
• D. To pump the lymph

Explanation: The main functions of skeletal muscle are to contract to produce movement, sustain body posture and position, maintain body temperature…

• A. H-zone
• B. M-Line
• C. Z-Line
• D. A-band

Explanation: The sarcomere is the fundamental unit of contraction and is defined as the region between two Z-lines.

• A. Triad
• B. Sarco-tubules
• C. T-system
• D. Neuromuscular junction

Explanation: The thousands of T-tubules of each muscle cell are collectively called T-system.

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

Explanation: The protein filament which binds to the calcium troponin. Troponin plays a central role in the calcium regulation of muscle contraction…

• A. CO2
• B. Accumulation lactic acid
• C. Fumaric acid
• D. Ethyl alcohol

Explanation: Muscle fatigue is caused by the accumulation of lactic acid. Lactic acid is formed and accumulated in the muscle under conditions of high…

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

Explanation: The actin molecules are arranged in two chains that twist around each other like a twisted double strand of pearls.Twisting around the…

• A. Origin
• B. Insertion
• C. Belly
• D. Bone

Explanation: The insertion and origin muscles are two different places where the bone is attached one at each end.

• A. M-line of sarcomere
• B. I-band of sarcomere
• C. H-band of sarcomere
• D. A-band of sarcomere

Explanation: A -band of sarcomere can polarize visible light. The A-band of a sarcomere consists of an overlap between light and heavy (actin and…

• A. Plasma membrane
• B. Sarcomere
• C. Sarcoplasm
• D. Sarcolemma

Explanation: The length of myofibril from one Z-line to the next is known as sarcomere A sarcomere is defined as the distance between the Z-lines.

• A. Muscle fiber
• B. Sarcomere
• C. Muscle bundle
• D. Myofibril

Explanation: Each muscle consists of muscle bundles, which are further composed of muscle fibers of cells.

• A. RER
• B. Golgi bodies
• C. Microfilaments
• D. Sarcoplasmic reticulum

Explanation: The nerve impulse is carried through the T-tubule to the adjacent sarcoplasmic reticulum (SR).

• A. 5-10 µm
• B. 1-2 µm
• C. 10-100 µm
• D. 50-100 mn

Explanation: The diameter of skeletal muscle fibres is in ranges of 10 - 100 µm.

• A. Z-line
• B. H-zone
• C. A-band
• D. M-line

Explanation: The thin filaments extends across the I-band and partly in A-band.

• A. H-zone
• B. M-zone
• C. Z-line
• D. A-band

Explanation: Each A-band has a lighter stripe in its mid-section called H-zone (H stands for "hele" mean bright).The H-zone is bisected by dark line…

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

Explanation: The protein that is complex of three polypeptide chains is called troponin.

• A. 5
• B. 6
• C. 10
• D. 12

Explanation: Each myosin filament is surrounded by 12 actin filaments on both end.

• A. Water
• B. Calcium
• C. Oxygen
• D. ATP

Explanation: After death, the amount of ATP in the body falls. Under these circumstances the bridges cannot be broken and so they remain firmly…

• A. Smooth
• B. Circular
• C. Cardiac
• D. Skeletal

Explanation: Majority of muscles tissue in your body are skeletal type.