All Free Biology MCQs with Answers

• A. Bone
• B. Joints
• C. Muscle fiber
• D. Heart

Explanation: The sarcolemma is the plasma membrane of the muscle cell and is surrounded by basement membrane and endomysial connective tissue.

• A. Cirrhosis
• B. Angina
• C. Epilepsy
• D. Paralysis

Explanation: Total muscle function loss, or paralysis, affects your entire body. It is often seen in people with severe spinal cord injuries..

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

Explanation: Z line is in a zig-zag manner which is a separation point between two sarcomeres.

• A. Muscle
• B. Fiber
• C. Myofibril
• D. Muscle fiber

Explanation: Sarcomeres are the smallest functional contractile unit of muscle, and myofibrils are striated muscle organelles that are comprised of…

• A. I only
• B. ll only
• C. I & III only
• D. II & III only
• E. I, II, & III

Explanation: Muscle contraction takes place when a NERVE IMPULSE from a motor neuron reaches a neuromuscular junction.The nerve impulse travels to…

• A. The vertebral column has 10 thoracic vertebrae.
• B. The joint between adjacent vertebrae is a fibrous joint.
• C. A decreased level of progesterone causes osteoporosis in old people.
• D. Accumulation of uric acid crystals in joints causes their inflammation

Explanation: Thoracic vertebrae are 12 in numbers. Joints between adjacent vertebrae are cartilagenous joints and the opposing surfaces are connected…

• A. Muscular dystrophy - Age related shortening of muscles
• B. Osteoporosis - Decrease in bone mass and higher chances of fractures with advancing age
• C. Myasthenia gravis - Autoimmune disorder which inhibits sliding of myosin filaments
• D. Gout - Inflammation of joints due to extra deposition of calcium

Explanation: Muscular dystrophy is characterised by progressive skeletal muscle weakness, defects in muscle proteins and the death of muscle cells and…

• A. Types of Diabetes - 4
• B. Cervical Vertebrae in Humans - 7
• C. Floating Ribs in Humans - 4 pairs
• D. Amino Acids Found in Proteins - 20

Explanation: Option c) "Floating Ribs in Humans - 4 pairs" gives an incorrect total number. Humans have two pairs of floating ribs, not four pairs.

• A. Both contain living cells
• B. Both contain varius types of living cells
• C. Both have ground matrix of collagen
• D. Both are part of endoskeleton

Explanation: Bones have living tissues like osteoblasts, osteocytes and osteoclasts, while cartilage have chondrocytes that produce large amount of…

• A. Collagen
• B. Actin
• C. Titin
• D. Albumin

Explanation: Collagen is the most abundant protein in animal's body. Actin is most abundant in muscles and albumin is most abundant in blood plasma.

• A. Calcium
• B. Magnesium
• C. Sodium
• D. Potassiumfibrous joint.

Explanation: Calcium ion plays an important role in muscle contraction. Calcium ions bind to troponin causing a change in its shape and position.Thus…

• A. Immune disorder affecting neuromuscular junction leading to fatigue
• B. High concentration of Ca2+ and Na+
• C. Decreased level of estrogen
• D. Accumulation of uric acid leading to inflammation of joints

Explanation: Osteoporosis is a reduction in bone mineral density, resulting in bones that are brittle and liable to fracture.

• A. Tetany
• B. Arthritis
• C. Spasm
• D. Fatigue

Explanation: Tetany refers to a condition in which the nerves innervating a particular muscle become overstimulated and cause involuntary contractions…

• A. Synovial joint
• B. Ball and Socket joint
• C. Fibrous joint
• D. Cartilaginous joint

Explanation: Fibrous joints are also called fixed or immovable joints because they do not allow any movement.

• A. Actin and myosin filaments do not shorten but rather slide pass each other
• B. When myofilaments slide pass each other, myosin filaments shorten while actin filaments do not shorten
• C. When myofilaments slide pass each other, actin filaments shorten while myosin filaments do not shorten
• D. Actin and myosin filaments shorten and slide pass each other.

Explanation: During muscle contraction, the laterally projecting heads (cross bridges) of the thick myosin myofilaments come in contact with the thin…

• A. Clavicle with scapula
• B. Humerus with scapula
• C. Clavicle with acromion
• D. Scapula with acromion.

Explanation: The glenoid cavity articulates with the head of the bone of the upper arm, the humerus, to form the shoulder joint.

• A. The neuromuscular junction
• B. The transverse tubules
• C. The myofibril
• D. The sacroplasmic reticulum.

Explanation: A neuron that transmits a stimulus to muscle tissue is called motor neuron.

• A. Central gap between actin filaments extending through myosin filaments in the A band
• B. Extension of myosin filaments in the central portion of the A band
• C. Absence of myofibrils in the central portion of the A band
• D. Central gap between myosin filaments in the the A band

Explanation: Each muscle fiber has many parallelly arranged myofibrils. Each myofibril contains many serially arranged units called sarcomere which are…

• A. Chracteristics - Fluid cartilage between two bones, limited movements, Examples - Knee joint
• B. Characteristics - Fluid filled between two joints, provides cushion, Examples - Skull bones
• C. Characteristics - Fluid filled synovial cavity between two bones, Examples - Joint between atlas and axis
• D. Characteristics - Lymph filled between two bones, limited movement, Examples - Gliding joint between carpals

Explanation: All articulations between bones that help in a certain kind of movement, are placed at a distance from each other to prevent friction…

• A. Sarcomere does not shorten
• B. A band remains same
• C. A, I bands and H-zone shorten
• D. Actin filaments shorten.

Explanation: According to slidingfilament theory of muscle contraction, the actin and myosin filaments slide past each other with the help of…