Q.1 Which type of muscle is responsible for voluntary movements in humans?
Cardiac muscle
Skeletal muscle
Smooth muscle
All of the above
Explanation - Skeletal muscles are attached to bones and are responsible for voluntary movements, unlike cardiac and smooth muscles.
Correct answer is: Skeletal muscle
Q.2 Which protein filaments are primarily involved in muscle contraction?
Actin and Myosin
Keratin and Collagen
Elastin and Fibrin
Tubulin and Dynein
Explanation - Actin (thin filament) and Myosin (thick filament) interact to produce muscle contraction through the sliding filament mechanism.
Correct answer is: Actin and Myosin
Q.3 Which type of joint allows the widest range of movement?
Hinge joint
Ball and socket joint
Pivot joint
Gliding joint
Explanation - Ball and socket joints (e.g., shoulder and hip) allow rotational movement and movement in multiple planes.
Correct answer is: Ball and socket joint
Q.4 What is the structural and functional unit of a skeletal muscle?
Myofibril
Sarcomere
Myosin filament
Actin filament
Explanation - The sarcomere is the smallest contractile unit of muscle, formed by repeating units of actin and myosin filaments.
Correct answer is: Sarcomere
Q.5 Which connective tissue connects muscle to bone?
Ligament
Tendon
Cartilage
Fascia
Explanation - Tendons are tough, fibrous tissues that attach muscles to bones, transmitting force to facilitate movement.
Correct answer is: Tendon
Q.6 The contraction of which muscle type is involuntary but striated?
Skeletal muscle
Cardiac muscle
Smooth muscle
All muscle types
Explanation - Cardiac muscles are striated like skeletal muscles but contract involuntarily to pump blood.
Correct answer is: Cardiac muscle
Q.7 Which part of the neuron stimulates muscle contraction?
Axon terminal
Cell body
Dendrites
Myelin sheath
Explanation - Axon terminals release neurotransmitters at the neuromuscular junction, stimulating muscle contraction.
Correct answer is: Axon terminal
Q.8 Which energy molecule directly powers muscle contraction?
ATP
Glucose
Creatine
NADH
Explanation - Adenosine triphosphate (ATP) provides the energy required for actin-myosin cross-bridge cycling during muscle contraction.
Correct answer is: ATP
Q.9 Which condition is caused by the deficiency of vitamin D affecting bone strength?
Rickets
Osteoporosis
Scurvy
Goiter
Explanation - Vitamin D deficiency leads to improper calcium absorption, weakening bones and causing rickets in children.
Correct answer is: Rickets
Q.10 Which of the following bones is part of the axial skeleton?
Femur
Humerus
Vertebra
Radius
Explanation - The axial skeleton includes the skull, vertebral column, and rib cage, providing support and protection.
Correct answer is: Vertebra
Q.11 Which movement decreases the angle between two bones?
Extension
Flexion
Abduction
Rotation
Explanation - Flexion reduces the angle at a joint, such as bending the elbow or knee.
Correct answer is: Flexion
Q.12 Which connective tissue connects bone to bone?
Tendon
Ligament
Cartilage
Fascia
Explanation - Ligaments are fibrous tissues connecting bones at joints, stabilizing and preventing excessive movement.
Correct answer is: Ligament
Q.13 Which muscle type is found in the walls of hollow organs?
Cardiac
Skeletal
Smooth
Striated
Explanation - Smooth muscles are involuntary and non-striated, found in organs like the intestines and blood vessels.
Correct answer is: Smooth
Q.14 The sliding filament theory explains the mechanism of:
Bone growth
Muscle contraction
Joint formation
Ligament repair
Explanation - During contraction, actin filaments slide over myosin filaments, shortening the sarcomere without changing filament length.
Correct answer is: Muscle contraction
Q.15 Which bone cell is responsible for bone formation?
Osteoblast
Osteoclast
Chondrocyte
Fibroblast
Explanation - Osteoblasts secrete the bone matrix and facilitate mineralization, leading to new bone formation.
Correct answer is: Osteoblast
Q.16 Which type of cartilage is found at the ends of long bones?
Fibrocartilage
Hyaline cartilage
Elastic cartilage
None of the above
Explanation - Hyaline cartilage covers joint surfaces of bones, reducing friction and acting as a shock absorber.
Correct answer is: Hyaline cartilage
Q.17 Which joint type allows movement around only one axis?
Hinge joint
Ball and socket joint
Saddle joint
Gliding joint
Explanation - Hinge joints, such as the elbow and knee, allow movement in one plane (flexion and extension).
Correct answer is: Hinge joint
Q.18 Which vitamin is essential for calcium absorption in bones?
Vitamin A
Vitamin D
Vitamin C
Vitamin K
Explanation - Vitamin D promotes calcium and phosphate absorption from the gut, crucial for bone mineralization.
Correct answer is: Vitamin D
Q.19 Which type of movement moves a limb away from the midline of the body?
Adduction
Abduction
Flexion
Extension
Explanation - Abduction moves a limb laterally away from the midline, like raising the arms sideways.
Correct answer is: Abduction
Q.20 Which molecule stores oxygen in muscle cells for rapid energy production?
Hemoglobin
Myoglobin
ATP
Creatine phosphate
Explanation - Myoglobin binds and stores oxygen in muscle cells, facilitating aerobic respiration during contraction.
Correct answer is: Myoglobin
Q.21 Which process allows bones to grow in length during childhood?
Ossification at epiphyseal plates
Bone remodeling
Synovial fluid secretion
Ligament stretching
Explanation - Long bones grow in length at the epiphyseal (growth) plates, where cartilage is replaced by bone.
Correct answer is: Ossification at epiphyseal plates
Q.22 Which structure forms the neuromuscular junction?
Axon terminal and sarcolemma
Myofibril and sarcomere
Ligament and tendon
Bone and cartilage
Explanation - The neuromuscular junction is the synapse where the motor neuron axon terminal communicates with the muscle fiber's sarcolemma.
Correct answer is: Axon terminal and sarcolemma
Q.23 Which type of muscle fatigue occurs due to oxygen debt and lactic acid accumulation?
Central fatigue
Peripheral fatigue
Psychological fatigue
Acute fatigue
Explanation - Peripheral fatigue occurs in muscles due to metabolic by-products like lactic acid and insufficient oxygen during intense exercise.
Correct answer is: Peripheral fatigue
Q.24 Which protein prevents actin and myosin from binding in relaxed muscle?
Tropomyosin
Troponin
Myosin
Actin
Explanation - Tropomyosin covers the myosin-binding sites on actin filaments, preventing contraction until calcium binds to troponin.
Correct answer is: Tropomyosin
Q.25 Which type of bone has a thin, flattened shape and provides protection?
Long bone
Short bone
Flat bone
Irregular bone
Explanation - Flat bones, like the skull and sternum, provide protection and large surfaces for muscle attachment.
Correct answer is: Flat bone