All Free Biology MCQs with Answers

• A. Failure of neuromuscular transmission in myasthenia gravis can prevent normal swallowing.
• B. Accumulation of urea and creatine in the joints causes their inflammation.
• C. An overdose of vitamin D causes osteoporosis.
• D. Rapid contractions of skeletal muscles cause muscle dystrophy.

Explanation: Myasthenia gravis is an autoimmune disorder in which autoantibodies bind to cholinergic receptors on muscle cells and impairs the ability…

• A. Calcitonin and thymosin - Thyroid hormones
• B. Pepsin and prolactin -Two digestive enzymes secreted in stomach
• C. Troponin and myosin - Complex proteins in striated muscles
• D. Secretin and rhodopsin - Polypeptide hormones

Explanation: Skeletal muscle fibres occur in bundles and are normally attached to the skeleton.

• A. Heart is involuntary and unstriated smooth muscle
• B. Intestine is striated and involuntary
• C. Thigh is striated and voluntary
• D. Upper arm is smooth muscle and fusiform in shape.

Explanation: A) Cardiac muscles are found in the wall of the heart. It is involuntary and slightly striated.B) Smooth muscles are found in…

• A. Sternum and ribs - Axial skeleton
• B. Clavicle and glenoid cavity - Pelvic girdle
• C. Humerus and ulna - Appendicular skeleton
• D. Malleus and stapes - Ear ossicles

Explanation: Each pectoral girdle consists of two bones, clavicle and scapula. The scapula (shoulder blade) consists of a sharp ridge, the spine and a…

• A. Ilium, ischium and pubis -> Coxal bones of pelvic girdle
• B. Actin, myosin, rhodopsin -> Muscle proteins
• C. Cytosine, uracil, thiamine -> Pyrimidines
• D. Malleus, incus, cochlea -> Ear ossicles

Explanation: The correct matching of the three items and their grouping category is: Ilium, ischium, and pubis -> Coxal bones of the pelvic girdle The…

• A. Hinge joint
• B. Gliding joint
• C. Ball and socket joint
• D. Pivot joint.

Explanation: Hinge joint is a form of diarthrosis (freely movable joint) that allows angular movement in one plane only, increasing or decreasing the…

• A. Collar bones - 3 pairs
• B. Salivary glands - 1 pair
• C. Cranial nerves - 10 pairs
• D. Floating ribs - 2 pairs

Explanation: In humans there are normally 12 pairs of ribs. The first seven pairs are attached directly to the sternum by costal cartilages and are…

• A. Pelvic girdle of mammals
• B. Pectoral girdle of mammals
• C. Skull of frog
• D. Sperm of mammals

Explanation: Each half of pectoral girdle is made up of two bones scapula and clavicle.

• A. Hinge joint between vertebrae
• B. Gliding joint between zygapo physes of the successive vertebrae
• C. Cartilaginous joint of skull bones
• D. Fibrous joint between phalanges

Explanation: Gliding joint permits sliding movements of two bones over each other. Hinge joint allows movements in one plane only.

• A. Bones will move freely at joint and no pain
• B. Bone less movable at joint and pain
• C. Bone will become unfixed
• D. Bone will become fixed

Explanation: Ligaments join a bone with another bone in movable/synovial joints. Torn ligaments make movement at joints very painful and restricted.

• A. Calcified cartilage
• B. Hyaline cartilage
• C. Elastic cartilage
• D. Fibrous cartilage

Explanation: Cartilage is an important component of skeleton. It consists of a firm matrix containing collagen and elastin fibres and cells in…

• A. Length of H-zone decreases and might disappear - Length of A-band remains constant
• B. Length of I-band remains constant
• C. Length of I band increases
• D. Length of the two Z-line increases

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

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

Explanation: A striated muscle fibre is bounded by sarcolemma. It shows alternating dark and light cross bands, the striations.

• A. Bony matter
• B. White fibrous cartilage
• C. Hyaline cartilage
• D. Areolar tissue

Explanation: Sternum is connected to ribs by hyaline cartilage (giving a shiny glass like appearance and gives flexibility and support at the joints).

• A. Coracoid
• B. Arytenoid
• C. Pterygoid
• D. Atlas

Explanation: Pterygoid is a process that extends from sphenoid bone of skull to form a plate like structure.

• A. Cartilaginous joint
• B. Angular joint
• C. Gliding joint
• D. Fibrous joint

Explanation: Cartilaginous joint is present between ribs and sternum. It allows only limited movement.

• A. Angular joint
• B. Hinge joint
• C. Pivot joint
• D. Saddle joint

Explanation: Pivot joint is present between atlas and the axis in humans. In this joint articular end of one bone is fixed while the other can rotate…

• A. Abductor
• B. Regulator
• C. Extensor
• D. Flexor

Explanation: Flexor muscle bends one part of a limb on another at a joint, e.g., biceps. It brings the fore arm towards the upper arm.

• A. 3 pairs
• B. 2 pairs
• C. 6 pairs
• D. 5 pairs

Explanation: There are twelve pairs of ribs which form the bony lateral walls of the thoracic cage.

• A. Femur
• B. Acetabulum
• C. Glenoid cavity
• D. Ilium

Explanation: The pectoral girdle lies on the posterolateral aspect of the upper region of the thorax. It consists of 2 bones : scapula and clavicle.