CBSE Class 11 Biology Locomotion and Movement Assignments

Question. Assertion :- All locomotions are movement but all movements are not locomotion.
Reason :- Such voluntory movements which result in a change of place or location are called locomotion.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Locomotion is generally for search of food, shelter, mate, suitable breeding grounds, favourable climatic conditions or to escape from enemies.
Reason :- Hydra can use its tentacle’s for capturing its prey and also use them for locomotion.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Amoeboid movement is effected by pseudopodia formed by the streaming of protoplasm.
Reason :- Cytoskeletal elements like microfilaments are involved in amoeboid movement.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The coordinated movements of cilia in the trachea help us in removing dust particles.
Reason :- The coordinated movement of cilia is controled by neural system.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Passage of ova through the female reproductive tract is also fascilitated by the ciliary movement.
Reason :- The co-ordinated movement of cilia is required for movement of ova in female reproductive tract.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Locomotion requires a perfect coordinated activity of muscular, skeletal and neural system.
Reason :- Locomotion in skeletal is controlled by CNS voluntarily.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Skeletal muscle’s are voluntray in nature.
Reason :- Contraction of skelectal muscle is controlled by motor area of cerebral cortex.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Visceral muscles are also called smooth muscles.
Reason :- Their activities are not under the voluntary control of the nervous system.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Cardiac muscle are autonomous and involuntary in nature.
Reason :- The nervous system does not control their activities directly.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Cardiac muscles are structurally striped.
Reason :- Cardiac muscles are uni nucleated and branched.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The dark band of muscles is also called ‘A’ or Anisotropic band.
Reason :- The dark band contains thick myosin filaments as well as thin actin filaments.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Each ‘F’ actin is a polymer of monomeric ‘G’-actin.
Reason :- ‘G’ actin is a globular protein or tertiary structure of protein.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- In the resting state a subunit of troponin masks the active binding site for myosin on the actin filaments.
Reason :- A complex protein troponin is distributed at regular intervals on the tropomyosin.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The globular head of meromyosin act as ATPase enzyme.
Reason :- The head of meromyosin is a tertiary structure of protein.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The calcium ions are essential for muscle contraction.
Reason :- Calcium ion are required for ATPase activities.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The junction between a motor neuron and sarcolemma of muscle fibre is called the motor end plate.
Reason :- Muscles contraction is initiated by a singal sent by the central nervous system via motor neuron.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- A neural singnal reaching neuro muscular junction, stimulate release of neurotransmitter, which generates an action potential in the sarcolemma.
Reason :- Action potential spreads through the cardiac muscle fibre and increase the intra cellular \( Ca^{+2} \) level by influx of \( Ca^{+2} \) from ECF.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Muscle’s fatigue is caused by accumulation of lactic acid.
Reason :- Lactic acid is formed by anaerobic breakdown of glycogen.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- White muscle fibres are faster than red muscle fibre.
Reason :- The white muscle fibres depend on anaerobic process for energy.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- A-band contain both myosin and actin filaments.
Reason :- In a resting state, the edges of thin filaments on either side of the thickfilaments partialy overlap the free end of thick filament.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Locomotion is a voluntary movement.
Reason :- Cells of Human body exhibits amoeboid, ciliary and muscular movement.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Striated muscles are directly under the voluntary control of the nervous system.
Reason :- Striated muscles are primarily involved in locomotory actions and changes of body posture.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Fascicles are held together by a common collagenous connective tissue layer called fascia.
Reason :- Fascia is also referred as syncytium.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Striped muscle fibre is a syncytium as the sarcoplasm contains many nuclei.
Reason :- The sarcoplasmic reticulum of the striped muscle fiber is the store house of calcium ions.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Band form by only actin protein is called Anisotropic Band.
Reason :- Band form by myosin protein is called isotropic band.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Sarcomere is the functional unit of contraction present between two successive ‘Z’ - Lines.
Reason :- Central part of myosin filament, not overlapped by actin filament is called ‘H’ - zone.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- The number of cervical vertebrae is almost seven in all mammals including humans.
Reason :- Sternum is a flat bone and located at the dorsal midline of the thorax.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- The \( 8^{th} \), \( 9^{th} \) & \( 10^{th} \) ribs joins with the \( 7^{th} \) rib with the help of hyaline cartilage.
Reason :- These are called vertebrochondral ribs
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- The \( 11^{th} \) & \( 12^{th} \) Pairs of ribs are not connected dorsally and therefore they are called floating ribs.
Reason :- Thoracic vertebrae, lumbar vertebrae, sternum and ribs together forms the rib cage.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Bones of the limbs along with girdles forms the appendicular skeleton.
Reason :- Each arm of human has 30 bones.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- In human wrist formed by 8 bones.
Reason :- In human palm formed by 5 bones.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Femur is the longest bone of the human body.
Reason :- Femur is formed by the fusion of Tibia and Fibula.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Patella is a sesamoid bone.
Reason :- It articulates with three bone.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Scapula is a large triangular flat bone situated in the ventral part of the thorax between the \( 2^{nd} \) and \( 7^{th} \) rib.
Reason :- The ventral, flat triangular body of scapula has an elevated ridge called spine.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Fibrous joint do not allow any movement.
Reason :- The bones involved in fibrous joint are joined together with the help of cartilage.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Human body cells exhibit three type of movements, amoeboid, ciliary and muscular.
Reason :- Macrophage show amoeboid movement, ciliated epithelium. Show ciliary movement limbs and tongue show muscular movement.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- A cup shaped bone patella cover the knee ventrally.
Reason :- Patella is a sesamoid bone.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Red fibres can also be called aerobic muscles.
Reason :- Red fibres contain plenty of mitochondria which can utilise large amount of oxygen stored them.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Osteoporosis is characterised by decreased bone mass & increased chances of fractures.
Reason :- Estrogen level increase in old age & excreted with urine.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- Sarcomere is distance between two I-bands.
Reason :- Sarcomere is unit of unstripped muscle.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Clavicle is a long slender bone with two curvatures.
Reason :- Clavicle is called as collar bone.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- Cardiac muscles are the muscles of heart.
Reason :- Heart muscles are striated, branched & involuntary.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- All movements are not locomotion.
Reason :- Only some of the movements result in a change of place or location.
(a) A
(b) B
(c) C
(d) D
Answer: A

Question. Assertion :- Muscle contraction is initiated by a signal sent by the central nervous system via a sensory neuron.
Reason :- Sensory neuron along with the muscle fibre connected to it constitute a motor unit.
(a) A
(b) B
(c) C
(d) D
Answer: D

Question. Assertion :- Arthritis is inflammation of joints.
Reason :- Gout is inflammation of joints due to accumulation of uric acid.
(a) A
(b) B
(c) C
(d) D
Answer: B

Question. Assertion :- First seven pairs of ribs are called true ribs.
Reason :- Ventrally ribs are attached to thoracic vertebra & dorsally connected to sternum.
(a) A
(b) B
(c) C
(d) D
Answer: C

Question. Assertion :- 40–50% of human body weight consist of muscles.
Reason :- Muscles may be skeletal, involuntary or cardiac which get attached to skeleton.
(a) A
(b) B
(c) C
(d) D
Answer: C

QUESTIONS

Very Short Answer Questions (1 mark each)

Question 1. How many bones are present in each limb?
Answer: There are 30 bones present in each limb (both upper limbs and lower limbs individually contain 30 bones).
In simple words: Each arm and leg has 30 bones.

Exam Tip: Remember the breakdown: Upper limb (Humerus = 1, Radius = 1, Ulna = 1, Carpals = 8, Metacarpals = 5, Phalanges = 14) and Lower limb (Femur = 1, Tibia = 1, Fibula = 1, Patella = 1, Tarsals = 7, Metatarsals = 5, Phalanges = 14).

Question 2. Why do skeletal muscle show steriation?
Answer: Skeletal muscles show striations due to the alternate distribution pattern of actin and myosin protein filaments arranged in repeating units called sarcomeres.
In simple words: The striped appearance is caused by the regular alternate arrangement of light and dark protein bands.

Exam Tip: Use the keywords 'actin', 'myosin', and 'alternating dark and light bands' to score full marks.

Question 3. Name last two pairs of ribs.
Answer: The last two pairs of ribs (11th and 12th pairs) are called floating ribs because their anterior ends are not attached to either the sternum or other ribs.
In simple words: The 11th and 12th rib pairs are known as floating ribs.

Exam Tip: Always specify both that they are pairs 11 and 12, and that they remain free anteriorly.

Question 4. Write the name of chemical that causes fatigue in the museles.
Answer: Lactic acid accumulation, resulting from anaerobic glycolysis during rigorous muscular activity, causes muscle fatigue.
In simple words: Lactic acid builds up in muscles during heavy exercise and causes tiredness and fatigue.

Exam Tip: Mention anaerobic breakdown of glycogen leading to lactic acid accumulation.

Question 6. What lubricate the freely movable joints at the shoulder ?
Answer: Synovial fluid, secreted by the synovial membrane, lubricates the freely movable joints at the shoulder.
In simple words: Synovial fluid acts as a natural lubricant inside movable joints like the shoulder.

Exam Tip: Note that question 5 was skipped in the source paper, but numbering is maintained as given.

Question 7. Name of longest bone of human body.
Answer: The femur (thigh bone) is the longest and strongest bone in the human body.
In simple words: The thigh bone (femur) is the longest bone.

Question 8. Give the first vertebra.
Answer: The first cervical vertebra is called the atlas.
In simple words: Atlas is the topmost bone of the vertebral column supporting the skull.

Exam Tip: Distinguish between the atlas (1st vertebra) and axis (2nd vertebra).

Question 9. Define a sarcomere.
Answer: A sarcomere is defined as the functional contractile unit of a myofibril situated between two successive Z lines.
In simple words: The segment of a myofibril between two Z lines is called a sarcomere.

Exam Tip: Mentioning 'functional unit of contraction' and 'between two Z lines' fetches full marks.

Question 10. Name the cup shaped bone that constitues the knee cap.
Answer: The patella is the protective, cup-shaped sesamoid bone that constitutes the knee cap.
In simple words: The kneecap is called the patella.

Exam Tip: Mention that it is a sesamoid bone formed by ossification of a tendon.

Short Answer Questions-II (2 marks each)

Question 11. Wrtie any two difference between cardiac muscle and skeletal muscle.
Answer: 1. Skeletal muscles are voluntary in action and attached to bones, whereas cardiac muscles are involuntary and found exclusively in the heart walls.
2. Skeletal muscle fibers are unbranched and cylindrical, whereas cardiac muscle fibers are branched, striated, and possess intercalated discs.
In simple words: Skeletal muscles are under our conscious control and unbranched, while heart muscles work automatically and are branched.

Exam Tip: Point out control (voluntary vs involuntary) and structure (branched vs unbranched) as key differences.

Question 12. Distinguish between red fibre and white fiber.
Answer: 1. Red muscle fibers contain a high concentration of myoglobin and numerous mitochondria, giving them a reddish appearance; white fibers have less myoglobin and fewer mitochondria.
2. Red fibers are adapted for sustained, slow aerobic work without fatigue; white fibers depend on anaerobic glycolysis and fatigue quickly.
In simple words: Red fibers have more myoglobin and do not tire easily, while white fibers have less myoglobin and tire quickly.

Exam Tip: Base your distinction on myoglobin content, mitochondrial count, and speed of fatigue.

Question 13. Name the two types of girdles found in human body and write their role.
Answer: The two types of girdles are:
1. Pectoral (Shoulder) girdle: Connects the upper limbs to the axial skeleton and provides articulation for the humerus.
2. Pelvic (Hip) girdle: Connects the lower limbs to the axial skeleton, bears body weight, and provides articulation for the femur.
In simple words: Pectoral girdle supports arms and pelvic girdle supports legs.

Exam Tip: Clearly name both girdles and specify their respective limb connections.

Question 14. State the role of calcium ions and ATP in muscle contraction.
Answer: 1. Calcium ions (\(\text{Ca}^{2+}\)): Bind to troponin on actin filaments, causing a conformational shift that unmasks the myosin-binding sites.
2. ATP (Adenosine Triphosphate): Hydrolysis of ATP provides energy for the formation and movement of cross-bridges (power stroke), and detachment of myosin head from actin during relaxation.
In simple words: Calcium unblocks binding sites so muscles can connect, and ATP provides the energy to pull and release.

Exam Tip: Mention troponin binding for calcium and energy provision / cross-bridge detachment for ATP.

Question 15. Name the bones of fore limb (hand) of human body. Give their number in each limb.
Answer: The bones of each forelimb (upper limb) and their numbers are:
1. Humerus = 1
2. Radius = 1
3. Ulna = 1
4. Carpals (Wrist bones) = 8
5. Metacarpals (Palm bones) = 5
6. Phalanges (Digits/Fingers) = 14
Total = 30 bones.
In simple words: Each arm has 30 bones including upper arm, forearm, wrist, palm, and fingers.

Exam Tip: List each bone type along with its precise count to ensure full marks.

Short Answer Questions-I (3 marks each)

Question 16. What makes the synovial joints freely movable? List any four types of synovial joints.
Answer: Synovial joints are freely movable because of the presence of a fluid-filled synovial cavity between the articulating surfaces of the two bones, enclosed by a joint capsule and lubricated by synovial fluid.
Four types of synovial joints are:
1. Ball and socket joint (e.g., shoulder and hip joints)
2. Hinge joint (e.g., knee and elbow joints)
3. Pivot joint (e.g., between atlas and axis)
4. Gliding joint (e.g., between carpals)
In simple words: A fluid-filled cavity makes them movable. Examples include hinge and ball-and-socket joints.

Exam Tip: Mention the synovial cavity, synovial fluid, and give accurate anatomical examples for the joint types.

Question 17. Name the category of bones forming the ribcage. How are these articulated to each other to form the cage?
Answer: The ribcage is formed by thoracic vertebrae, ribs, and the sternum.
Articulation: Dorsally, all 12 pairs of ribs are attached to the thoracic vertebrae. Ventrally, the first 7 pairs (true ribs) are connected directly to the sternum through hyaline cartilage; pairs 8, 9, and 10 (false ribs) articulate with the cartilage of the 7th rib; and the last 2 pairs (floating ribs) remain free anteriorly.
In simple words: Ribs attach to the backbone at the back and to the breastbone (directly or indirectly) at the front, forming a protective cage.

Exam Tip: Clearly differentiate between true ribs, false ribs, and floating ribs based on their ventral attachments.

Question 18. How are actin and myosin filament arranged in a muscle fibre?
Answer: 1. Actin filaments (thin filaments) are anchored at their ends to the 'Z' line and extend towards the center of the sarcomere.
2. Myosin filaments (thick filaments) occupy the central region of the sarcomere (A-band), held together in the middle by the 'M' line.
3. In the overlap zone, each thick filament is surrounded by six thin filaments, and each thin filament is surrounded by three thick filaments.
In simple words: Thin actin filaments are attached to Z lines, while thick myosin filaments lie in the center, overlapping during contraction.

Exam Tip: Mention Z-lines for actin, M-line for myosin, and the overlapping band structure.

Question 19. Mention the factor which is responsible for the following: (i) Tetany (ii) Gout (iii) osteoporosis
Answer: (i) Tetany: Caused by low \(\text{Ca}^{2+}\) ion level in body fluids (hypocalcemia), leading to rapid spasms in muscles.
(ii) Gout: Caused by the accumulation of uric acid crystals in joints, leading to inflammation.
(iii) Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures, often due to decreased estrogen levels or calcium deficiency.
In simple words: Tetany is due to low calcium, Gout is due to uric acid crystals, and Osteoporosis is weak bones due to aging or mineral loss.

Question 20. Explain the important steps of sliding filament theory of muscle contraction.
Answer: 1. Signal Initiation: A neural signal reaches the neuromuscular junction, releasing a neurotransmitter that generates an action potential in the sarcolemma.
2. Calcium Release: The action potential triggers the release of calcium ions (\(\text{Ca}^{2+}\)) from the sarcoplasmic reticulum into the sarcoplasm.
3. Exposure of Active Sites: Calcium ions bind to troponin on the actin filament, removing the masking of active sites for myosin.
4. Cross-bridge Formation: Energized myosin heads bind to the exposed active sites on actin to form a cross-bridge, utilizing energy from ATP hydrolysis.
5. Power Stroke and Sliding: The attached myosin head pulls the actin filament towards the center of the A-band, shortening the sarcomere (contraction).
6. Relaxation: Upon cessation of the stimulus, calcium ions are pumped back into the sarcoplasmic reticular cisternae, actin sites are re-masked, and the muscle relaxes as actin filaments slide back.
In simple words: Nerves stimulate muscles, calcium unlocks binding sites, myosin pulls actin using ATP energy to shorten the muscle, and relaxation occurs when calcium is pumped back.

Exam Tip: Write the steps sequentially: Neural signal -> Calcium release -> Troponin binding -> Cross-bridge formation -> Sliding of actin -> Relaxation.