Q1. Assertion: Cardiac muscles are involuntary.
Reason: The nervous system does not control their activities directly.
Correct Answer: (c)
Cardiac muscles are involuntary because they are not under conscious control. However, their activity is regulated by the autonomic nervous system (which influences heart rate). The reason states that the nervous system does not control them directly, which is false – autonomic nerves do modulate cardiac function. Hence assertion is true, but reason is false.
Q2. Which are correct for 'White muscle fibres'? (i) Low myoglobin content. (ii) Few mitochondria. (iii) High amount of sarcoplasmic reticulum.
Correct Answer: (a)
White fibres have low myoglobin, few mitochondria, but abundant SR for rapid calcium release. All three are correct.
Q3. Muscles with high myoglobin content and many mitochondria are called:
Correct Answer: (b)
Red fibres are rich in myoglobin (which gives them a red colour) and contain numerous mitochondria, making them well‑suited for aerobic respiration and sustained activity. White fibres have low myoglobin and few mitochondria, relying on anaerobic metabolism. Fast‑twitch fibres are typically white.
Q4. Match the bone total in limbs:
A. Each limb
30 bones
B. Total (4 limbs)
120 bones
Correct Answer: (a)
Each upper limb has 30 bones (arm, forearm, hand) and each lower limb has 30 bones (thigh, leg, foot). Total for four limbs = 120 bones. Both are correct.
Q5. Match the myofibril bands with pigments:
Band
Protein
A. Light band (I)
Actin
B. Dark band (A)
Myosin
Correct Answer: (a)
The I‑band contains actin (thin) filaments, and the A‑band contains myosin (thick) filaments. Both associations are correct.
Q6. Assertion: Red muscle fibres are also called aerobic muscles.
Reason: They can utilise the large amount of oxygen stored in them for ATP production.
Correct Answer: (a)
Red fibres have high myoglobin, which binds oxygen, and numerous mitochondria, enabling them to generate ATP aerobically. This makes them highly fatigue‑resistant and suitable for sustained activities. The reason correctly explains why they are called aerobic muscles.
Q7. Match the vertebral column regions:
Column-I (Region)
Column-II (No. of bones)
A. Cervical
(I) 12
B. Thoracic
(II) 7
C. Lumbar
(III) 5
Correct Answer: (a)
Cervical vertebrae = 7, thoracic = 12, lumbar = 5. This standard formula (C7, T12, L5) is correct, giving A‑II, B‑I, C‑III.
Q8. Assertion: Visceral muscles are called involuntary muscles.
Reason: Their activities are not under the voluntary control of the nervous system.
Correct Answer: (a)
Visceral muscles (smooth muscles) are involuntary because we cannot consciously control their contraction. The reason correctly states that their activities are not under voluntary nervous control, which is the defining characteristic of involuntary muscles. Thus both are true and the reason explains the assertion.
Q9. The storehouse of calcium ions in muscle fibres is the:
Correct Answer: (c)
The sarcoplasmic reticulum (SR) is a specialised endoplasmic reticulum in muscle cells that sequesters and releases calcium ions (Ca²⁺) during contraction. It acts as a reservoir for Ca²⁺, which is essential for the excitation‑contraction coupling. Golgi, sarcolemma, and mitochondria do not serve as primary Ca²⁺ stores.
Q10. Assertion: Clavicle is commonly called the collar bone.
Reason: It is a long slender bone with two curvatures.
Correct Answer: (b)
The clavicle is indeed commonly known as the collar bone, and it is a long slender bone with an S‑shaped curvature. However, the reason describes its morphology, not the origin of its common name (which comes from its collar‑like position). Both statements are true, but the reason does not explain why it is called collar bone.
Q11. Assertion: All locomotions are movements but all movements are not locomotions.
Reason: Locomotion involves a change in place or location, while movement may not.
Correct Answer: (a)
Locomotion is a specific type of voluntary movement that results in spatial displacement. All locomotion is movement, but not all movements (e.g., blinking, heartbeat) lead to a change of place. The reason correctly defines locomotion and explains why the assertion is true.
Q12. Muscle contraction is initiated by a signal sent by the:
Correct Answer: (b)
Voluntary muscle contraction begins with a neural impulse from the central nervous system (brain or spinal cord) that travels via motor neurons to the neuromuscular junction. The sensory system relays information, endocrine system uses hormones, and the lymphatic system is not involved in initiating contraction.
Q13. Assertion: Sarcomere is the functional unit of contraction.
Reason: It is the portion of the myofibril between two successive Z-lines.
Correct Answer: (a)
The sarcomere is the smallest contractile unit of a myofibril, defined as the segment between two adjacent Z‑lines. It is within this region that the actin and myosin filaments interact to produce shortening. The reason precisely defines the sarcomere, explaining why it is the functional unit.
Q14. Ciliary movement in humans is commonly seen in:
Correct Answer: (a)
Ciliated epithelium lines many internal tubular organs such as the trachea, bronchi, and fallopian tubes. The beating of cilia helps move mucus, dust particles, or ova along these passages. Skeletal muscles, heart, and limbs are not lined by cilia; they rely on different types of movements.
Q15. Select correct statements for 'Osteoporosis': (i) Age-related disorder. (ii) Characterised by decreased bone mass. (iii) Increased chances of fractures.
Correct Answer: (a)
Osteoporosis is age‑related, reduces bone mass, and increases fracture risk. All three are correct.
Q16. Which protein masks the active binding sites for myosin on the actin filaments during rest?
Correct Answer: (a)
In a resting muscle, tropomyosin lies in the groove of the actin helix and physically covers the myosin‑binding sites on actin. This prevents cross‑bridge formation. Troponin, when bound to Ca²⁺, moves tropomyosin away to expose the sites. Thus the masking protein is tropomyosin, not troponin.
Q17. Voluntary movements which result in a change of place or location are called:
Correct Answer: (b)
Locomotion is defined as a voluntary movement that brings about a change in the organism’s position or location. It is distinct from other movements like streaming or ciliary movement, which may not involve displacement of the whole body. Thus, the correct term is locomotion.
Q18. In Paramoecium, which structure helps in both movement of food and locomotion?
Correct Answer: (c)
Cilia are tiny hair‑like projections covering the surface of Paramecium. They beat in coordinated waves to propel the organism through water and also create water currents that sweep food into the oral groove. Flagella are longer and used for propulsion in other organisms, while pseudopodia are for amoeboid movement. Thus cilia serve both functions.
Q19. Identify correct statements for 'Rib types' (Pairs): (i) True ribs: 1-7. (ii) False ribs: 8-10. (iii) Floating ribs: 11-12.
Correct Answer: (a)
True ribs are pairs 1‑7; false ribs 8‑10; floating ribs 11‑12. All are correct.
Q20. The dark band of a myofibril is also called:
Correct Answer: (c)
The dark band seen under a microscope is the A‑band (anisotropic band), which contains overlapping thick (myosin) and thin (actin) filaments. The I‑band is light and isotropic, the Z‑line is a thin disc marking the boundary of sarcomeres. Therefore, the dark band is correctly termed the A‑band.
Q21. Assertion: Heavy meromyosin (HMM) forms the cross arm.
Reason: The head and short arm project outwards from the surface of the myosin filament.
Correct Answer: (a)
HMM (heavy meromyosin) consists of the globular head and a short arm that protrude from the myosin filament, forming cross‑bridges that interact with actin. The reason describes this protrusion, which is the structural basis for cross‑bridge formation, thus explaining the assertion.
Q22. Muscle is a specialised tissue of ______ origin.
Correct Answer: (c)
All muscle tissues in vertebrates develop from the mesoderm, the middle germ layer during embryogenesis. Ectoderm gives rise to nervous tissue and epidermis, endoderm forms internal linings, and epidermis is an outer layer. Thus muscle is of mesodermal origin.
Q23. Match the number of bones in human skeletal system parts:
Column-I (Part)
Column-II (No. of bones)
A. Axial skeleton
(I) 8
B. Cranial bones
(II) 80
C. Facial region
(III) 14
D. Ear ossicles (Total)
(IV) 6
Correct Answer: (a)
Axial skeleton has 80 bones; cranial bones are 8; facial bones are 14; total ear ossicles are 6 (3 per ear). Thus A‑II, B‑I, C‑III, D‑IV is correct.
Q24. Muscle fibre is a syncytium because it contains:
Correct Answer: (b)
A syncytium is a multinucleated cell formed by the fusion of multiple cells. Skeletal muscle fibres are syncytial because they contain many nuclei within a single continuous cytoplasm (sarcoplasm). A single nucleus would mean a typical cell, and absence of nucleus is not the case; many mitochondria are a feature but not the definition of syncytium.
Q25. The neurotransmitter released at the neuromuscular junction is:
Correct Answer: (c)
Acetylcholine (ACh) is the neurotransmitter released by motor neurons at the neuromuscular junction. It binds to receptors on the sarcolemma, triggering depolarisation and muscle contraction. Dopamine, serotonin, and adrenaline are neurotransmitters/hormones but are not involved in skeletal muscle activation at the NMJ.
Q26. Each actin (thin) filament is made of two ______ actins helically wound to each other.
Correct Answer: (b)
Thin filaments are composed of two helical strands of F‑actin (filamentous actin), which are polymers of G‑actin (globular actin) monomers. Meromyosins are components of myosin, and troponins are regulatory proteins. Hence the correct term is F‑actins.
Q27. Match the parts of a Myosin Monomer:
Column-I
Column-II
A. Heavy meromyosin (HMM)
(I) Tail
B. Light meromyosin (LMM)
(II) Head and short arm
Correct Answer: (a)
HMM consists of the globular head and a short arm; LMM is the tail portion. Thus A‑II, B‑I.
Q28. The plasma membrane of a muscle fibre is called:
Correct Answer: (b)
The muscle fibre (cell) is enclosed by a plasma membrane specifically termed the sarcolemma. The cytoplasm is called sarcoplasm; fascia is connective tissue covering muscles; and a fascicle is a bundle of muscle fibres. Therefore, sarcolemma is the correct membrane.
Q29. Match the limb bones:
Column-I (Common name)
Column-II (Anatomical name)
A. Thigh bone
(I) Clavicle
B. Knee cap
(II) Femur
C. Collar bone
(III) Patella
Correct Answer: (a)
Thigh bone = femur; knee cap = patella; collar bone = clavicle. Thus A‑II, B‑III, C‑I.
Q30. Assertion: Tetany causes wild contractions of muscles.
Reason: It is caused by high calcium levels in body fluid.
Correct Answer: (c)
Tetany is characterised by involuntary, spasmodic muscle contractions due to increased excitability of nerves. The actual cause is low calcium levels (hypocalcemia) in the blood, not high calcium. High calcium would depress nerve excitability. Thus the assertion is true but the reason is false.
Q31. Amoeboid movement in human blood is exhibited by:
Correct Answer: (c)
Specialised cells of the immune system, such as macrophages and leucocytes, can change shape and move by extending pseudopodia, a process called amoeboid movement. Red blood cells and platelets lack this ability; lymphocytes are a subset of leucocytes but not the only ones that show this movement. Hence the correct answer is macrophages and leucocytes.
Q32. Match the rib articulation:
Side
Attachment
A. Dorsal
Thoracic vertebrae
B. Ventral
Sternum (True ribs)
Correct Answer: (a)
Ribs articulate dorsally with thoracic vertebrae and ventrally with the sternum (true ribs) or via cartilage. Both descriptions are correct.
Q33. Assertion: The first seven pairs of ribs are true ribs.
Reason: They are dorsally attached to the thoracic vertebrae and ventrally connected to the sternum.
Correct Answer: (a)
True ribs (1‑7) have a direct anterior attachment to the sternum via their own costal cartilages and a posterior attachment to the thoracic vertebrae. The reason accurately describes this dual connection, which is the defining characteristic of true ribs.
Q34. The first vertebra is the:
Correct Answer: (b)
The first cervical vertebra is the atlas, which supports the skull and articulates with the occipital condyles, allowing nodding movements. The axis is the second vertebra, sacrum and coccyx are fused vertebrae at the base of the spine. Hence the first vertebra is the atlas.
Q35. Which of the following describes 'Myasthenia gravis' correctly? (i) Auto immune disorder. (ii) Affects neuromuscular junction. (iii) Leads to paralysis of skeletal muscle.
Correct Answer: (a)
Myasthenia gravis is autoimmune, affects NMJ, and can cause muscle weakness and paralysis. All statements are correct.
Q36. Assertion: The skull is dicondylic in humans.
Reason: It articulates with the vertebral column with the help of two occipital condyles.
Correct Answer: (a)
The human skull has two occipital condyles that articulate with the atlas (first vertebra), making it dicondylic. This dual articulation allows nodding and slight rotation. The reason describes the anatomical feature, thereby explaining the assertion.
Q37. Match the ear ossicles:
Bone
No. per ear
A. Malleus
1
B. Incus
1
C. Stapes
1
Correct Answer: (a)
Each middle ear contains one malleus, one incus, and one stapes. Thus all three are present as a single bone per ear, making the first option correct.
Q38. Match the locomotion site with organism:
Site
Organism
A. Canal system
Sponges
B. Tentacles
Hydra
Correct Answer: (a)
Sponges use water currents through their canal system for movement of particles and sometimes whole body; Hydra uses tentacles for locomotion. Both matches are correct.
Q39. Assertion: Fibrous joints do not allow any movement.
Reason: The flat skull bones fuse end-to-end with the help of dense fibrous connective tissues.
Correct Answer: (a)
Fibrous joints (sutures) are immovable; the bones are joined by dense fibrous connective tissue with no gap. The reason describes the sutures of the skull as a prime example, explaining why such joints allow no movement. Both statements are true and the reason correctly explains the assertion.
Q40. Identify the correct statements regarding smooth muscles: (i) They are located in the walls of hollow visceral organs. (ii) They are striated in appearance. (iii) They are involuntary muscles.
Correct Answer: (a)
Smooth muscles are found in viscera, are non‑striated, and are involuntary. Statement (ii) is false, so only (i) and (iii) are correct.
Q41. The globular head of meromyosin is an active ______ enzyme.
Correct Answer: (a)
The globular head (S1 fragment) of myosin possesses ATPase activity – it hydrolyses ATP to ADP and inorganic phosphate, releasing energy for the power stroke. While it is a hydrolase, the specific name is ATPase. Ligases join molecules and isomerases rearrange structures; they are not the function of the myosin head.
Q42. How many cervical vertebrae are present in almost all mammals, including humans?
Correct Answer: (c)
Almost all mammals have seven cervical vertebrae, from mice to giraffes and humans. Exceptions include sloths and manatees. Twelve is the number of thoracic vertebrae, five is lumbar, and one is the coccyx (fused). Thus seven is the correct count.
Q43. Match the skull bones:
Type
Total
A. Cranial
(I) 8
B. Facial
(II) 14
Correct Answer: (a)
There are 8 cranial bones and 14 facial bones, making A‑I, B‑II.
Q44. Which of the following regarding the pectoral girdle is/are correct? (i) Consists of a clavicle and a scapula. (ii) Scapula is a large triangular flat bone. (iii) Clavicle is the collar bone.
Correct Answer: (a)
The pectoral girdle is made of clavicle (collar bone) and scapula (triangular flat bone). All statements are true.
Q45. Regarding the human skull, which statements are true? (i) Total of 22 bones. (ii) 8 cranial and 14 facial bones. (iii) Cranium forms the brain box.
Correct Answer: (a)
The skull has 22 bones (8 cranial + 14 facial). The cranium indeed encloses the brain. All are correct.
Q46. Match the following for rib types:
Column-I (Rib type)
Column-II (Pairs)
A. True ribs
(I) 1st to 7th
B. False ribs
(II) 11th and 12th
C. Floating ribs
(III) 8th, 9th, 10th
Correct Answer: (a)
True ribs are pairs 1‑7; false ribs are 8‑10; floating ribs are 11‑12. Thus A‑I, B‑III, C‑II is the correct matching.
Q47. Match the properties of bones and cartilages:
Structure
Matrix Nature
A. Bone
(I) Very hard due to calcium salts
B. Cartilage
(II) Slightly pliable due to chondroitin salts
Correct Answer: (a)
Bone matrix is hardened by calcium phosphate salts; cartilage matrix is flexible due to chondroitin sulfate. Hence A‑I, B‑II.
Q48. Match the types of joints with their examples:
Column-I (Joint Type)
Column-II (Example)
A. Fibrous joint
(I) Between adjacent vertebrae
B. Cartilaginous joint
(II) Between atlas and axis
C. Pivot joint
(III) Sutures in skull
D. Ball and socket
(IV) Between humerus and pectoral girdle
Correct Answer: (a)
Fibrous joints are exemplified by skull sutures; cartilaginous joints occur between vertebrae; pivot joint is between atlas and axis; ball‑and‑socket joint is between humerus and pectoral girdle. Hence A‑III, B‑I, C‑II, D‑IV.
Q49. Which of the following phylum/organism is correctly matched with its locomotory structure? (i) Hydra – Tentacles. (ii) Amoeba – Protoplasmic streaming. (iii) Euglena – Flagella.
Correct Answer: (a)
Hydra uses tentacles, Amoeba uses protoplasmic streaming (pseudopodia), Euglena uses flagella. All matches are correct.
Q50. About what percentage of the body weight of a human adult is contributed by muscles?
Correct Answer: (b)
In a typical human adult, muscles constitute about 40‑50% of total body weight. This includes skeletal, cardiac, and smooth muscles. The other ranges are either too low or too high; for instance, bone mass is about 15‑20% and fat varies, but muscle mass is consistently around this range.
Q51. Assertion: Accumulation of lactic acid causes muscle fatigue.
Reason: It is formed due to aerobic breakdown of glycogen.
Correct Answer: (c)
Lactic acid buildup during intense exercise contributes to muscle fatigue and soreness. However, lactic acid is produced by anaerobic glycolysis, not aerobic breakdown. Aerobic respiration yields CO₂ and water. Hence the assertion is true, but the reason is false.
Q52. Regarding 'Meromyosin', which are true? (i) It is the monomer of myosin. (ii) HMM component is the head/short arm. (iii) LMM component is the tail.
Correct Answer: (a)
Meromyosin is the myosin monomer; HMM includes head and short arm; LMM is the tail. All are correct.
Q53. Identify correct statements for joints: (i) Joints act as a fulcrum for movement. (ii) Fibrous joints allow no movement. (iii) Synovial joints have a fluid-filled cavity.
Correct Answer: (a)
Joints serve as fulcra; fibrous joints are immovable; synovial joints have synovial fluid. All are correct.
Q54. Regarding the 'Vertebral column' formula: (i) C7, T12, L5, S1 (fused), Co1 (fused). (ii) Total 26 vertebrae.
Correct Answer: (a)
The formula (C7, T12, L5, S1, Co1) sums to 26. Both statements are correct.
Q55. Assertion: Synovial joints allow considerable movement.
Reason: They are characterised by the presence of a fluid-filled synovial cavity.
Correct Answer: (a)
Synovial joints are freely movable (diarthroses) due to the synovial fluid that lubricates and reduces friction between articulating bones. The reason describes the key structural feature that enables smooth movement, thus explaining the assertion.
Q56. The only U-shaped bone present at the base of the buccal cavity is:
Correct Answer: (b)
The hyoid bone is a U‑shaped bone located in the neck, just above the larynx, at the base of the buccal cavity. It does not articulate with any other bone and serves as an attachment point for tongue and neck muscles. The mandible is the lower jaw, maxilla is the upper jaw, and ethmoid is a cranial bone.
Q57. Match the girdles and bones:
Column-I (Girdle)
Column-II (Bones)
A. Pectoral Girdle
(I) Ilium, Ischium, Pubis
B. Pelvic Girdle
(II) Clavicle, Scapula
Correct Answer: (a)
Pectoral girdle consists of clavicle and scapula; pelvic girdle is formed by ilium, ischium, and pubis. So A‑II, B‑I.
Q58. Match the following for synovial joints:
Joint
Location
A. Hinge joint
(I) Knee
B. Gliding joint
(II) Between carpals
C. Saddle joint
(III) Between carpal and metacarpal of thumb
Correct Answer: (a)
Hinge joint is found at the knee; gliding joint between carpals; saddle joint at the thumb (carpometacarpal). Hence A‑I, B‑II, C‑III.
Q59. Correct statements for 'Pelvic Girdle': (i) Two coxal bones. (ii) Coxal bone formed by fusion of Ilium, Ischium and Pubis. (iii) Coxal bones meet at pubic symphysis.
Correct Answer: (a)
Pelvic girdle consists of two coxal bones; each is formed by ilium, ischium, pubis; they meet anteriorly at pubic symphysis. All correct.
Q60. Identify correct statements about 'Sarcomere' changes during contraction: (i) Distance between Z-lines decreases. (ii) I-band reduces. (iii) A-band length remains constant.
Correct Answer: (a)
During contraction, sarcomere shortens (Z‑lines approach), I‑band shortens, and A‑band length stays the same. All statements are correct.
Q61. Assertion: Troponin is a complex protein.
Reason: It is distributed at regular intervals on the tropomyosin.
Correct Answer: (b)
Troponin is indeed a complex of three subunits (TnC, TnI, TnT). Its distribution along tropomyosin is a true structural feature, but this distribution does not explain why it is considered 'complex'; the complexity refers to its subunit composition. Hence both are true, but the reason does not correctly explain the assertion.
Q62. In the resting state, the central part of the thick filament not overlapped by thin filaments is:
Correct Answer: (c)
The H‑zone is the central region of the A‑band where only thick filaments are present and thin filaments do not reach. In a relaxed muscle, this zone is visible. The I‑band contains only thin filaments, the M‑line is the middle of the thick filament, and the sarcomere is the whole unit.
Q63. Regarding 'Myofibril' bands: (i) Striated appearance due to Actin and Myosin distribution. (ii) I-band is the light band. (iii) A-band is the dark band.
Correct Answer: (a)
Striations arise from alternating actin and myosin; I‑band is light, A‑band is dark. All correct.
Q64. Match the pelvic girdle components:
Term
Description
A. Acetabulum
(I) Cavity for thigh bone articulation
B. Pubic symphysis
(II) Formed by two halves of girdle ventrally
Correct Answer: (a)
The acetabulum is the socket for the head of the femur; the pubic symphysis is the ventral fusion of the two coxal bones. Therefore A‑I, B‑II.
Q65. The functional unit of contraction between two successive 'Z' lines is:
Correct Answer: (b)
The sarcomere is the repeating unit of a myofibril, defined as the region between two adjacent Z‑lines. It is the smallest contractile unit; during contraction, the sarcomere shortens. The sarcolemma is the cell membrane, a fascicle is a bundle of fibres, and the H‑zone is a central region within the A‑band.
Q66. Match the muscle fiber types:
A. Red fibres
Aerobic
B. White fibres
Anaerobic
Correct Answer: (a)
Red fibres are aerobic due to high myoglobin and mitochondria; white fibres are anaerobic. Both statements are accurate, so 'Both are correct'.
Q67. Which type of muscle is also known as 'smooth muscle'?
Correct Answer: (b)
Visceral muscles are found in the walls of hollow internal organs such as the stomach, intestine, and blood vessels. They lack striations and appear smooth under the microscope, hence the name 'smooth muscle'. Skeletal and cardiac muscles are striated, and 'striated' is not a type of muscle but a characteristic.
Q68. Which of the following statements regarding types of movement is/are correct? (i) Amoeboid movement is effected by pseudopodia. (ii) Ciliary movement occurs in the trachea. (iii) Passage of ova through female reproductive tract is facilitated by ciliary movement.
Correct Answer: (a)
All three statements are true: amoeboid movement uses pseudopodia; ciliary movement occurs in the trachea (to move mucus) and also in the fallopian tubes to transport ova. Thus all are correct.
Q69. Which of the following is correct? (i) Alfonso Corti was an Italian anatomist. (ii) Human skeleton has 206 bones. (iii) Arthritis is inflammation of joints.
Correct Answer: (a)
Alfonso Corti was indeed an Italian anatomist; the human skeleton has 206 bones; arthritis is joint inflammation. All are correct.
Q70. Assertion: Gout is the inflammation of joints.
Reason: It is due to the accumulation of urea crystals.
Correct Answer: (c)
Gout is indeed an inflammatory joint disease, but it is caused by the deposition of uric acid crystals, not urea. Urea accumulation is seen in uremia, not gout. Therefore, the assertion is true, but the reason is false.
Q71. Assertion: All mammals have seven cervical vertebrae.
Reason: This includes a few exceptions like man.
Correct Answer: (d)
The assertion is false because not all mammals have seven cervical vertebrae (e.g., sloths and manatees have different numbers). The reason is true in that there are exceptions, although the example given (man) is incorrect – humans have seven and are not exceptions. Hence assertion is false, but reason is true.
Q72. Match the parts of the sarcomere:
Column-I
Column-II
A. I-band
(I) Bisects the thick filaments (middle)
B. A-band
(II) Contains only actin
C. M-line
(III) Contains both actin and myosin
D. Z-line
(IV) Bisects the I-band
Correct Answer: (a)
I‑band contains only actin (thin) filaments; A‑band has both actin and myosin; M‑line runs through the centre of the A‑band; Z‑line bisects the I‑band. Thus A‑II, B‑III, C‑I, D‑IV is correct.
Q73. Assertion: White muscle fibres depend on anaerobic process for energy.
Reason: They possess very few mitochondria and less myoglobin.
Correct Answer: (a)
White fibres have low myoglobin and few mitochondria, which makes them less capable of aerobic respiration. Consequently, they rely heavily on anaerobic glycolysis for ATP, leading to quicker fatigue. The reason provides the structural basis for the anaerobic dependence, so it correctly explains the assertion.
Q74. Which of the following is true for the 'Ear Ossicles'? (i) Total 6 bones in the body. (ii) Malleus, Incus and Stapes. (iii) Found in the middle ear.
Correct Answer: (a)
There are 3 ossicles per ear (total 6); they are malleus, incus, stapes; located in middle ear. All are correct.
Q75. During contraction, which band retains its original length?
Correct Answer: (b)
According to the sliding filament theory, the A‑band (which contains the entire length of the thick filaments) does not change its length during contraction. The I‑band shortens, the H‑zone disappears, and the sarcomere shortens as the Z‑lines move closer together. Hence the A‑band retains its length.
Q76. Assertion: The 11th and 12th pairs of ribs are called floating ribs.
Reason: They are not connected ventrally to the sternum.
Correct Answer: (a)
Floating ribs (11th and 12th) are so named because their anterior ends do not attach to the sternum; they end in the abdominal musculature. The reason gives the exact anatomical feature that defines them, thus correctly explaining the assertion.
Q77. Match the disorders with their descriptions:
Column-I (Disorder)
Column-II (Description)
A. Tetany
(I) Low estrogen levels
B. Osteoporosis
(II) Rapid spasms due to low Ca++
C. Myasthenia gravis
(III) Progressive degeneration (genetic)
D. Muscular dystrophy
(IV) NMJ autoimmune disorder
Correct Answer: (a)
Tetany is caused by low Ca²⁺ leading to spasms; osteoporosis is linked to low estrogen; myasthenia gravis is autoimmune at the NMJ; muscular dystrophy is a genetic degenerative disease. Therefore A‑II, B‑I, C‑IV, D‑III.
Q78. The human axial skeleton comprises how many bones?
Correct Answer: (c)
The axial skeleton consists of 80 bones: the skull (22 bones), vertebral column (26), ribs (24), and sternum (1). The total 206 is the entire skeleton, 126 is the appendicular skeleton, and 22 is just the skull bones. Therefore, the correct number is 80.
Q79. Assertion: Muscle fibre is a syncitium.
Reason: The sarcoplasm of muscle fibre contains many nuclei.
Correct Answer: (a)
A syncytium is a multinucleated cell. Skeletal muscle fibres have multiple nuclei within a common cytoplasm (sarcoplasm), which is the result of fusion of many myoblasts during development. The reason correctly describes this multinucleated condition, explaining why the fibre is a syncytium.
Q80. Match the following for contractile protein structures:
Column-I
Column-II
A. Troponin
(I) Distributed at regular intervals
B. Tropomyosin
(II) Two filaments running close to F-actins
Correct Answer: (a)
Troponin is found at regular intervals on tropomyosin; tropomyosin consists of two strands that wind around the F‑actin filaments. So A‑I, B‑II.
Q81. Match the types of muscles with their characteristics:
Column-I (Muscle)
Column-II (Nature)
A. Skeletal muscle
(I) Smooth, Involuntary
B. Visceral muscle
(II) Striated, Involuntary
C. Cardiac muscle
(III) Striated, Voluntary
Correct Answer: (a)
Skeletal muscle is striated and voluntary (A‑III); visceral (smooth) muscle is non‑striated and involuntary (B‑I); cardiac muscle is striated but involuntary (C‑II). This matches the standard classification.
Q82. Assertion: Myasthenia gravis affects the neuromuscular junction.
Reason: It is an autoimmune disorder.
Correct Answer: (a)
Myasthenia gravis is an autoimmune disease where antibodies attack acetylcholine receptors at the neuromuscular junction, causing muscle weakness and fatigue. The reason correctly identifies its autoimmune nature, which directly explains why the NMJ is affected.
Q83. Identify correct features of the 'Sarcomere': (i) Portion between two Z-lines. (ii) Functional unit of contraction. (iii) Contains one A-band and two half I-bands.
Correct Answer: (a)
Sarcomere is between Z‑lines, is the functional unit, and has one A‑band flanked by two half I‑bands. All correct.
Q84. Match the following for bone counts in hands:
Part
Number
A. Carpals
(I) 8
B. Metacarpals
(II) 5
C. Phalanges
(III) 14
Correct Answer: (a)
Each hand has 8 carpals, 5 metacarpals, and 14 phalanges (2 in thumb, 3 in each other finger). Hence A‑I, B‑II, C‑III.
Q85. Match the following regarding muscle fatigue:
Cause
Mechanism
A. Fatigue
Accumulation of lactic acid
B. Lactic acid source
Anaerobic breakdown of glycogen
Correct Answer: (a)
Muscle fatigue is associated with lactic acid buildup; lactic acid is produced by anaerobic glycolysis. Both statements are correct.
Q86. Assertion: Ribs are called bicephalic.
Reason: Each rib has two articulation surfaces on its dorsal end.
Correct Answer: (a)
Most ribs have two facets (heads) on the dorsal end for articulation with the vertebral bodies – hence they are termed bicephalic. The reason accurately states this feature, explaining the assertion correctly.
Q87. Assertion: The 8th, 9th and 10th pairs of ribs are called true ribs.
Reason: They join the seventh rib with the help of hyaline cartilage.
Correct Answer: (d)
The 8th, 9th, and 10th ribs are false ribs (vertebrochondral) because they do not directly attach to the sternum; they connect to the seventh rib via costal cartilages. The assertion that they are true ribs is false. The reason correctly describes their indirect attachment, so the assertion is false but the reason is true.
Q88. The monomeric protein that constitutes the thick (myosin) filament is:
Correct Answer: (b)
Myosin filaments are polymers of many meromyosin molecules. Each myosin molecule consists of two heavy chains and two pairs of light chains, and the monomer is often called meromyosin. G‑actin is the monomer for actin, troponin and tropomyosin are regulatory proteins.
Q89. Identify the correct sequence of events in muscle contraction: (i) Release of Acetylcholine at motor-end plate. (ii) Increase in Ca++ levels in sarcoplasm. (iii) Binding of Ca++ with a subunit of troponin. (iv) Formation of cross bridge.
Correct Answer: (a)
The correct order is: (i) ACh release → (ii) Ca²⁺ release from SR → (iii) Ca²⁺ binding to troponin → (iv) cross‑bridge formation. The option 'All are correct in sequence' states this order.
Q90. Identify the correct statements about the vertebral column: (i) Formed by 26 units called vertebrae. (ii) First vertebra is atlas. (iii) Articulates with skull via occipital condyles.
Correct Answer: (a)
The adult vertebral column has 26 vertebrae (including fused sacrum and coccyx); the first is atlas; it articulates with the skull at occipital condyles. All correct.
Q91. Which of the following describes the structure of actin (thin) filaments correctly? (i) Made of two 'F' actins helically wound. (ii) Tropomyosin runs close to 'F' actins. (iii) Troponin is distributed at regular intervals.
Correct Answer: (a)
Thin filaments are composed of two F‑actin strands, with tropomyosin lying along the groove, and troponin distributed periodically. All three statements are accurate.
Q92. Assertion: H-zone is the central part of the thick filament.
Reason: It is the region not overlapped by thin filaments in a resting state.
Correct Answer: (a)
The H‑zone lies in the middle of the A‑band and contains only thick filaments; in a relaxed muscle, thin filaments do not extend into this region. The reason correctly defines the H‑zone by its lack of overlap, which explains its central location within the thick filament array.
Q93. Select the correct statements for human ribs: (i) 12 pairs of ribs are present. (ii) 11th and 12th pairs are floating ribs. (iii) Ribs are bicephalic.
Correct Answer: (a)
Humans have 12 pairs of ribs; the last two (11th and 12th) are floating; each rib typically has two articular facets (bicephalic). All three are correct.
Q94. Regarding 'ATPase' activity: (i) Located in the myosin head. (ii) Hydrolyses ATP to release energy. (iii) Energy used for cross bridge formation.
Correct Answer: (a)
Myosin head has ATPase activity; it hydrolyzes ATP, providing energy for cross‑bridge cycle. All statements are correct.
Q95. Which statements about 'Tetany' are correct? (i) Rapid spasms. (ii) Caused by low Ca++ in body fluid. (iii) Wild contractions of muscles.
Correct Answer: (a)
Tetany causes rapid, wild muscle spasms due to low calcium levels. All three are correct.
Q96. Assertion: Osteoporosis is characterized by decreased bone mass.
Reason: Decreased levels of estrogen is a common cause in elderly women.
Correct Answer: (a)
Osteoporosis involves a reduction in bone density and mass, making bones fragile. In postmenopausal women, estrogen levels drop, leading to increased bone resorption. The reason correctly identifies a major cause, and thus explains the assertion.
Q97. Which statements regarding red muscle fibres are correct? (i) They have high myoglobin content. (ii) They contain plenty of mitochondria. (iii) They are also called aerobic muscles.
Correct Answer: (a)
Red fibres have high myoglobin, many mitochondria, and are adapted for aerobic respiration. All three statements are correct.
Q98. Match the following for bone counts in feet:
Part
Number
A. Tarsals
(I) 7
B. Metatarsals
(II) 5
C. Phalanges
(III) 14
Correct Answer: (a)
Each foot has 7 tarsals, 5 metatarsals, and 14 phalanges (same as hand, but tarsals differ). Thus A‑I, B‑II, C‑III.
Q99. Assertion: Cytoskeleton elements are involved in amoeboid movement.
Reason: Microfilaments are part of the cytoskeleton.
Correct Answer: (a)
Amoeboid movement is driven by the cytoskeleton, particularly actin microfilaments, which polymerise and depolymerise to extend pseudopodia. The reason correctly identifies microfilaments as cytoskeletal components, thus explaining how the cytoskeleton is involved.
Q100. Match the vertebral column total:
A. Serially arranged units
Vertebrae
B. Total units
26
Correct Answer: (a)
The vertebral column is composed of vertebrae (serially arranged) and totals 26 bones in adults (7 cervical + 12 thoracic + 5 lumbar + 1 sacrum + 1 coccyx). Both statements are correct.