All Free Biology MCQs with Answers

• A. Synostosis
• B. Symphysis
• C. Syndesmosis
• D. Interosseous membrane

Explanation: Option A: Synostosis is the union or fusion of adjacent bones by the growth of a bony substance, either as a normal process during growth…

• A. Thick filaments
• B. M-line
• C. H-zone
• D. All of these options are correct

Explanation: The H zone-the central region of the A zone-contains only thick filaments and is shortened during contraction.

• A. The A-band becomes short.
• B. The I-band elongates.
• C. There is no change in the sarcomere length.
• D. The Z-lines get closer.

Explanation: When a sarcomere contracts, the Z lines move closer together, and the I-band gets smaller.

• A. Nerve impulse
• B. Energy
• C. Calcium
• D. All of these options are correct

Explanation: Muscle contraction begins when the nervous system generates a signal. The signal, an impulse called an action potential, travels through a…

• A. Oxygen
• B. Adenosine
• C. Cytosine
• D. Phosphate

Explanation: By adding a phosphate group, ADP is transformed into ATP. The phosphate group is transferred by creatine phosphate, which forms creatinine…

• A. Flexion and extension
• B. Adduction and abduction
• C. Rotation
• D. Extension flexion and rotation

Explanation: A pivot joint allows rotation around an axis, e.g., between the first and second neck vertebrae.

• A. Cervical region
• B. Lumbar region
• C. Pelvic region
• D. Thoracic region

Explanation: The coccyx, also known as the tailbone, is a small, triangular bone resembling a shortened tail located at the bottom of the spine in the…

• A. Appendicular skeleton
• B. Hydrostatic skeleton
• C. Exoskeleton
• D. Axial skeleton

Explanation: The axial skeleton forms a vertical axis that includes the head, neck, back, and chest.

• A. Protein and Sodium Bicarbonate
• B. Protein and Calcium Carbonate
• C. Protein and Potassium Carbonate
• D. Protein and Sodium Carbonate

Explanation: Chitin is translucent and tough in its pure form, but it also combines with other materials to form a strong outer structure.

• A. Hip and shoulder joints
• B. Hip and knee joints
• C. Shoulder and knee joints
• D. Hip and elbow joints

Explanation: The ball and socket joint also called as the spheroidal joint is a joint in which the ball-like rounded surface of a bone moves within a…

• A. Exoskeleton
• B. Appendages
• C. Endoskeleton
• D. Reduced mitosis

Explanation: As the body underneath the exoskeleton grows, the animal begins to outgrow its tough exterior.

• A. Sarcolemma
• B. Epimysium
• C. Both A and B
• D. Microtubules

Explanation: The outermost sheath of connective tissue covering each muscle is called 'Epimysium'.

• A. Trachea
• B. Collenchyma cells
• C. Sclereids
• D. Tracheids

Explanation: The trachea is an organ, not a cell so it cannot be Option A. Collenchyma cells can reach up to 2.5mm. Sclereids are typically 1mm.

• A. Chlorenchyma
• B. Mesoderm
• C. Sclerenchyma
• D. Mesenchyme

Explanation: Chlorenchyma, Mesoderm, and Sclerenchyma are cellular so the correct answer is D: Mesenchyme.

• A. Motor unit
• B. Neuromuscular junction
• C. Neural unit
• D. Microtubules

Explanation: A motor unit consists of a motor neuron and all the muscle fibers it supplies so the correct answer is Option A.

• A. Silica
• B. Polyester threads
• C. Groups of cell fibers
• D. Calcium and phosphorous

Explanation: Option (c) suggests that muscles are composed of groups of cell fibers. This statement is partly correct.

• A. Tendon
• B. Ligament
• C. Reticular tissue
• D. Cartilage

Explanation: Option (a) is correct. Tendons are fibrous connective tissues that attach muscles to bones.

• A. Better adapted for slow sustained activities.
• B. For energy, they depend on fatty acids.
• C. The myoglobin content is high.
• D. Possess mitochondria in huge numbers.

Explanation: Option A is incorrect as smooth muscles are better adapted for slow sustained activity.

• A. Cardiac tissue
• B. Connective tissue
• C. Epithelial tissue
• D. Nervous tissue

Explanation: Correct option is B. Cartilage is a form of connective tissue. Cartilage is a strong, flexible connective tissue that protects your joints…

• A. Tropomyosin
• B. Troponin C
• C. Troponin I
• D. Troponin T

Explanation: Correct option is B. Calcium is released from the sarcoplasmic reticulum through calcium ion channels when the membrane of the T-tubular…