All Free Biology MCQs with Answers

• A. ATP
• B. ADP
• C. Calcium
• D. Sodium

Explanation: During muscle contraction, the calcium gates of the smooth endoplasmic reticulum open releasing calcium into the cytosol.

• A. Motor unit neurons only transmit one action potential during a contraction
• B. Large motor units are innervated first in a muscle, followed by smaller units in order to have a smooth contraction
• C. The neuron releases epinephrine across the synaptic cleft in order to stimulate an action potential in the sarcolemma
• D. Finger muscles are typically composed of smaller motor units

Explanation: Option A;A motor unit is made up of a motor neuron and all of the skeletal muscle fibers innervated by the neuron's axon terminals…

• A. Hyaline cartilage
• B. Elastic cartilage
• C. Fibro cartilage
• D. None of these

Explanation: hyaline cartilage is the most common type of cartilage in your body. It lines your joints and caps the ends of your bones.

• A. It actively pumps calcium ions into its lumen.
• B. It releases calcium ions by active transport.
• C. It creates the proteins needed to cover the actin filaments.
• D. It releases calcium once an action potential reaches the sarcolemma.

Explanation: The sarcoplasmic reticulum is a critical storage site for calcium ions, taking up the ions from the cytoplasm.

• A. Rheumatoid Arthritis
• B. Osteoarthritis
• C. Gouty arthritis
• D. Psoriatic arthritis

Explanation: Osteoarthritis. This is the most common form of arthritis and it is considered a non-inflammatory form of arthritis.

• A. Network of tubules
• B. Vesicles
• C. Digestive Enzymes
• D. Both A and B

Explanation: ER is made up of a network of tubules and also has vesicles that transport processed molecules to a target location

• A. Sarcomere
• B. Microtubules
• C. Filaments
• D. M-line

Explanation: Each sarcomere consists of light and dark bands. These bands are made up of actin and myosin filaments.

• A. The myosin heads will not bind the actin filaments
• B. Troponin will not be activated
• C. Tropomyosin will remain bound to actin
• D. Calcium ions will not be released into a synapse

Explanation: The calcium ions required for muscle contraction are released from the SR while those involved in the transmission of an impulse across a…

• A. Closer together
• B. Farther apart
• C. Towards the Z-line
• D. Both B and C

Explanation: During a cross bridge cycle, the actin and myosin filaments slide inwards towards the centre of the sarcomere and the distance between…

• A. The amount of movement allowed by them
• B. Type of bones they join
• C. Nature of structure they have
• D. Both Options A and C are correct

Explanation: Joints are indeed classified based on the nature of the structure they possess.

• A. It helps move the myosin head into a high energy position
• B. It allows tropomyosin to be pulled away from the actin filament
• C. Both options A and B are correct
• D. None of these

Explanation: To enable muscle contraction, tropomyosin must change conformation and uncover the myosin-binding site on an actin molecule, thereby…

• A. Synaptic cleft
• B. Neuron
• C. Neuromuscular junction
• D. Both options B and C are correct

Explanation: The neuromuscular junction is the connection point between a motor neuron and a skeletal muscle fiber.

• A. It has a light and dark band
• B. It has only one nucleus
• C. It is under involuntary control
• D. None of these options are correct

Explanation: Skeletal muscles or striated muscles show alternate light and dark regions under a microscope. Hence, A is the correct option.

• A. Chondritis
• B. Arthralgia
• C. Synovitis
• D. Rheumatism

Explanation: Option A : Chondritis is the inflammation of the cartilage. Option: B Medical terminology for pain in joints is 'arthritis' or…

• A. Sarcomere
• B. Myofibril
• C. Myosin filament
• D. M-line

Explanation: Muscle contraction occurs when the thin actin and thick myosin filaments slide past each other.

• A. Myofibrils make up about 15% of the contents of a muscle fiber.
• B. Actin filaments are arranged so that six actin filaments surround each myosin filament.
• C. Both A and B are correct
• D. None of these

Explanation: Six actin filaments surround each myosin filament, producing a hexagonal array.

• A. Z band
• B. A band
• C. I band
• D. H zone

Explanation: The light bands are called I bands and contain only thin filaments. The dark bands are called A bands and contain thick and thin…

• A. Saddle joint
• B. Condyloid joint
• C. Ball and socket joint
• D. Hinge joint

Explanation: Hinge joints are a type of joint that functions much like the hinge on a door, allowing bones to move in one direction back and forth with…

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

Explanation: Sarcomere is the region between two Z lines

• A. Flexor muscles
• B. Extensor muscles
• C. Adductor muscles
• D. Abductor muscles

Explanation: Option D is the correct option because an abductor muscle is any of the muscles that cause movement of a limb away from the midplane of…