Locomotion and Movement — Class 11 MCQs with Answers

Locomotion and Movement — important questions & MCQs with answers (Class 11 Biology)

6 solved questions from this chapter's difficulty levels, each with its answer and explanation. Tap an option to check yourself.

0 of 6 answered

1. Q1 of 6Easy

   Voluntary muscles are:

   ASkeletal/striatedBCardiacCSmoothDAll
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   Answer: Skeletal/striated

   Explanation: Skeletal muscle is striated and voluntary, moved consciously via tendons on bone. Cardiac muscle is also striated but involuntary — that overlap is the tempting wrong pick here.

2. Q2 of 6Easy

   Number of bones in adult human body:

   A500B300C100D206
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   Answer: 206

   Explanation: Adults have 206 bones: axial 80 + appendicular 126. Children start near 270–300 because bones like skull plates and sacral segments haven't fused yet.

3. Q3 of 6Medium

   Smooth muscles are found in walls of:

   ATongueBSkeletal limbs onlyCHeart wallDInternal organs like stomach and intestine
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   Answer: Internal organs like stomach and intestine

   Explanation: Smooth muscle lines internal organ walls like the stomach and intestine, contracting involuntarily for peristalsis — the tongue and limbs instead use skeletal muscle.

4. Q4 of 6Medium

   Sliding filament theory: contraction is due to:

   ANerves contractingBBones movingCActin sliding over myosinDCells dividing
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   Answer: Actin sliding over myosin

   Explanation: Sliding filament theory: thin actin filaments slide over stationary thick myosin filaments via cross-bridge cycling powered by ATP — myosin doesn't shrink, it pulls actin inward.

5. Q5 of 6Hard

   Osteoporosis is characterised by:

   ADecreased bone mass and densityBJoint inflammationCMuscle paralysisDExcess cartilage
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   Answer: Decreased bone mass and density

   Explanation: Osteoporosis is reduced bone mass and density from calcium/oestrogen loss, common post-menopause — distinct from arthritis, which is joint inflammation, not bone loss.

6. Q6 of 6Hard

   Assertion: All locomotions are movements. Reason: All movements are locomotions.

   ABoth falseBBoth true; R explains ACA true, R falseDA false, R true
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   Answer: A true, R false

   Explanation: Locomotion is always a movement, so the assertion is true — but not all movement is locomotion (a heartbeat doesn't relocate the body), so the reason is false.

Locomotion and Movement notes: key concepts (Class 11 Biology)

Movement ranges from amoeboid crawling to the coordinated pull of skeletal muscle. This chapter examines muscle ultrastructure, the sliding-filament theory and its cross-bridge cycle powered by ATP and triggered by calcium, the axial and appendicular skeleton, the three classes of joints, and common musculoskeletal disorders.

Types of movement

Cells move by amoeboid (pseudopodia), ciliary (in trachea and oviducts) or muscular means; muscular movement enables true locomotion in animals.

Muscle types

Skeletal muscle is striated and voluntary, smooth muscle is unstriated and involuntary, and cardiac muscle is striated but involuntary.

Muscle ultrastructure

A muscle fibre holds many myofibrils; each myofibril has repeating sarcomeres of thick myosin (A band) and thin actin (I band) filaments.

Sarcomere

The sarcomere lies between two Z lines; the H zone is myosin-only and the I band actin-only. On contraction both the I band and H zone shrink.

Contractile proteins

Actin carries tropomyosin and troponin that mask the myosin-binding sites; myosin heads have ATPase activity and form the cross-bridges.

Sliding-filament theory

Contraction is actin filaments sliding over myosin toward the sarcomere centre; the filaments themselves never shorten, only the sarcomere does.

Role of calcium

A nerve signal releases Ca²⁺ from the sarcoplasmic reticulum; Ca²⁺ binds troponin, shifting tropomyosin to expose actin sites for myosin heads.

Cross-bridge cycle

Myosin binds actin, the power stroke pulls the thin filament, ATP detaches the head, and ATP hydrolysis re-cocks it for another cycle.

Red vs white fibres

Red fibres are rich in myoglobin and mitochondria for aerobic, fatigue-resistant work; white fibres rely on anaerobic glycolysis for quick, tiring bursts.

Axial skeleton

The axial skeleton's 80 bones — skull, vertebral column, ribs and sternum — form the central axis and shield the brain, cord and heart.

Appendicular skeleton

The appendicular skeleton's 126 bones are the limb bones plus the pectoral and pelvic girdles that anchor them; adult bones total 206.

Joints

Joints are fibrous (immovable, skull sutures), cartilaginous (slightly movable, between vertebrae) or synovial (freely movable, with a fluid-filled cavity).

Synovial joint types

Synovial joints include ball-and-socket (shoulder, hip), hinge (knee, elbow), pivot, gliding and saddle types, each allowing a characteristic motion.

Disorders

Myasthenia gravis, muscular dystrophy and tetany affect muscle; arthritis, osteoporosis (low bone mass) and gout (uric-acid crystals) affect the skeleton.