(1) Skeletal muscles are made of bundles of muscle fibers. Each fiber contains many myofibrils, which are made of repeating contractile units called sarcomeres. (2) Sarcomeres contain overlapping thin actin filaments and thick myosin filaments. During muscle contraction, myosin heads bind to and pull on actin filaments, causing the filaments to slide towards each other. (3) Muscle contraction is initiated by motor neurons stimulating the release of calcium from the sarcoplasmic reticulum. Calcium binds to troponin, exposing actin binding sites for myosin to form cross-bridges and drive contraction.

1. MUSCLES
Final Practice Sheet - 01

2. 1. Regulatory proteins of skeletal muscle are :
(A) Actin and myosin (B) Troponin and Tropomyosin
(C) Actinin and Troponin (D) Tropomyosin and Myosin

3. 2. Given below is the diagrammatic representation of a sarcomere, mark
the option with correct description of the structures labelled as A, B,
C and D in the same :
(A) A – Elastic fibre that bisects I-band
B – Length of this band reduces during muscle
(B) B – Consist of myosin filaments
C – Length of this band remains same during muscle contraction
(C) C – Light band that contains actin Filaments
D – Central part of thick filament, not overlapped by thin filaments.
(D) A – Thin filaments are firmly attached to it.
D – It retain the length during muscle contraction.

4. 3. Consider the following diagram showing four stages (A-D) of muscle
contraction and select the option with correct information regarding
these stages :
(A) A-Myosin head not attached with actin due to masking of active sites
B-Binding of energized myosin heads to the exposed active sites on
actin filaments
(B) A-Utilising the energy by myosin heads from ATP hydrolysis
C-Rotation of myosin heads and sliding of actin filaments over myosin
(C) C-Utilising the energy by myosin heads from ATP hydrolysis
D-Sliding of actin filaments towards the centre of the A-band
(D) C-Formation of cross bridges
D-Breaking of cross - bridges

5. 4. All the given statements are correct w.r.t the mechanism of muscle
contraction except one. Choose the incorrect statement:
(A) Muscle contraction is initiated by a signal sent by the central nervous
via sensory neuron
(B) Action potential for contraction spreads through the muscle fibre and
causes the release of calcium ions into the sarcoplasm
(C) Increase in calcium ions level leads to the binding of calcium with a
submit of troponin on actin filaments and thereby remove the
masking of active sits of myosin
(D) Utilising the energy from ATP hydrolysis the myosin head now binds
to the exposed active sites on actin to form a cross bridge

6. 5. (i) Each myosin (thick) filament is a polymerized protein
(ii) Each actin (thin) filament is made of two “F” (filamentous) actin
helically wound to each other
(iii) Two filaments of another protein, Troponin run close to the “F”
actins throughout its length
(iv) Each meromyosin has two important parts globular head with a
short arm and a tail.
How many above statements are correct?
(A) Two (B) Four
(C) Three (D) One

7. 6. Each fasciculus of skeletal muscle fibre is surrounded by :
(A) Epimysium (B) Perimysium
(C) Endomysium (D) Sarcolemma

8. 7. (i) All locomotions are movements but all movements are not
locomotions
(ii) In paramecium, cilia helps in the movement of food through
cytopharynx and in locomotion as well.
(iii) Streaming of protoplasm in the unicellular organism like
Amoeba is a simple form of movement
(iv) Hydra can use its tentacles for capturing its prey and also use
them for locomotion.
How many above statements are correct?
(A) Four (B) Three
(C) Two (D) One

9. 8. Identify the A, B, C in the given diagram :
A B C
(A) Muscle Muscle bundle Muscle cell
(B) Muscle bundle Muscle cell Sarcolemma
(C) Fascicle Muscle fibre Myofibril
(D) Muscle bundle Myofibril Sarcolemma

10. 9. Identify the A, B, C, D and E in the given diagram :
A B C D E
(A) Z-line Sarcomere I-band H-zone A-bond
(B) M-line A-band I-band Z-line Sarcomere
(C) Z-line A-band I-band H-zone Sarcomere
(D) Z-line Sarcomere M-line H-zone A-bond

11. 10. Anatomical unit of muscle is :
(A) Sarcomere (B) Muscle fibre
(C) Myofibrils (D) Muscle bundles

12. 11. In the alimentary and reproductive tract which type of muscles
present :
(A) Striated muscle (B) Smooth muscle
(C) Cardiac muscle (D) Skeletal muscle

13. 12. Identify the parts labelled A, B and C in given diagram and select the
right option about correct sequence of them.
(A) Myosin, Troponin, Tropomyosin
(B) Tropomyosin, Troponin, F-actin
(C) F-actin, Troponin, Tropomyosin
(D) Troponin, Tropomyosin, F-actin

14. 13. All the muscles have following special properties except :
(A) Excitability (B) Extensibility
(C) Autorhythmicity (D) Contractility

15. 14. (i) Plenty of mitochondria
(ii) Myogloblin content is high
(iii) Amount of sarcoplasmic reticulum is high
(iv) Depend on aerobic process for ATP production
(v) Gives a reddish appearance
How many points are correct about Red fibres of muscle?
(A) Three (B) Four
(C) Five (D) Six

16. 15. “Myosin binding site” present on :
(A) Actin protein (B) Myosin Protein
(C) Tropomyosin protein (D) Troponin protein

17. 16. Identify A, B, C and D in the given diagram and choose the correct
option :
(A) A- ATP binding site (B) A- Actin binding site
B- Actin binding site B- ATP binding site
C- Head C- Head
D- Tail D- Cross arm
(C) A- ATP binding site (D) A- ATP enzyme
B- Actin binding site B- Actin binding site
C- Head C- Cross arm
D- Cross arm D- Head

18. 17. In Myasthenia gravis acetylcholine :
(A) Receptors on motor end plate are reduced
(B) Secretion from nerve terminals is reduced
(C) Esterase activity is inhibited
(D) Secretion from nerve terminal enhanced

19. 18. Arrange the following events of muscle contraction in the sequence :
(I) Generate an action potential in the sarcolemma
(II) Form a cross bridge
(III) Release a neurotransmitter (Acetylcholine)
(IV) Release of calcium ions
(V) Pulls the attached actin filaments towards the centre of “A” band
(VI) Remove the masking of active sites for myosin
The correct option is :
(A) I → II → III → IV → V → VI (B) III → IV → I → II → VI → V
(C) III → I → IV → II → V → VI (D) III → I → IV → VI → II → V

20. 19. Contraction of muscles fibres takes place by the sliding of :
(A) Thin filaments over the actin filaments
(B) Thick filaments over thin filaments
(C) Thin filaments over the thick filaments
(D) Thick filaments overt the myosin filaments

21. 20. Muscular disorder in List-I are correctly matched with their
characters in List-II
(A) A→ (iii), (iv), B→ (vi), (ii), C→(i), (v)
(B) A→ (iii), (v), B→ (vi), (ii), C→(i), (iv)
(C) A→ (i), (v), B→ (ii), (vi), C→(iii), (iv)
(D) A→ (iii), (v), B→ (vi), (i), C→(ii), (iv)
List - I List - II
A Muscular dystrophy (i) Rapid spasms in muscle
B Myasthenia gravis (ii) Affecting Neuromuscular junction
C Tetany (iii) Progressive degeneration of skeletal
muscle
(iv) Due to law Ca++ in body fluid
(v) Due to genetic disorder
(vi) Auto immune disorder

22. 21. Each organised skeletal muscle in our body is made of a number of
(A) held together by a common collagenous connective tissue layer
called (B) . Each muscle bundle contains a number of (C) which is
lined by the plasma membrane called (D).
Choose the option which correctly fills the blanks labelled as A to D
A B C D
(A) Muscle bundles Endomysium Myofibrils Sarcolemma
(B) Fascicles Fascia Myofibrils Sarcolemma
(C) Muscle bundles Endomysium Muscle fibre Perimycium
(D) Fascicles Fascia Muscle fibre Sarcolemma

23. 22. Correctly match column -I with column-II.
(A) A = i, B = ii, C = iii, D = iv, E = v
(B) A = iv, B = v, C = i, D = iii, E = ii
(C) A = iv, B = v, C = ii, D = iii, E = i
(D) A = ii, B = iii, C = i, D = v, E = iv
Column - I Column - II
A. Tetany (i) Auto immune disorder
B. Osteoporosis (ii) Progressive degeneration of
skeletal muscle
C. Muscular dystrophy (iii) Inflammation of joints
D. Arthiritis (iv) Rapid spasms in muscle
E. Myasthenia gravis (v) Bone mass decreased

24. 23. Motor neuron along with muscle fibres are connected and constitute a :
(A) Neuro muscular junction (B) Motor end plate
(C) Motor unit (D) Both (A) and (B)

25. 24. In a resting state, the central part of thick filaments which is not
overlapped by thin filaments is called :
(A) A-band (B) M-line
(C) H-zone (D) I-band

26. 25. Amoeboid movement is found in :
(A) Limbs, jaw (B) Macrophages, Leucocytes
(C) Trachea, Fallopian tube (D) Tongue, Leucocytes

27. 26. Which points are correct with regarding of skeletal muscles?
(i) Their activities are under the voluntary control of the nervous
system
(ii) They are located in the inner walls of visceral organs
(iii) They are primarily involved in locomotory actions and changes
of body postures.
(iv) They have no striped appearance
(A) ii, iv (B) ii, iii
(C) i, iv (D) i, iii

28. 27. Which points are correct about visceral muscles ?
(A) These are located in the inner walls of hallow visceral organs of
the body
(B) They do not exhibit any striations
(C) Their activities are not under the voluntary
(D) All of the above

29. 28. The functional unit of contraction is :
(A) Muscle fibre (B) Sarcomere
(C) Sarcosomes (D) Sarcoplasm

30. 29. A neural signal reaching neuromuscular junction release a
neurotransmitter namely :
(A) Dopamine (B) Acetylcholine
(C) GABA (D) Glycine

31. 30. Muscles contains a red coloured oxygen storing pigament called :
(A) Haemoglobin (B) Sarcosome
(C) Myoglobin (D) Haemoerythrin

32. 31. Least blood supply will be present in :
(A) Skeletal muscle (B) Cardiac muscle
(C) Smooth muscle (D) All of these

33. 32. Contractile unit of muscle fibres :
(A) Muscle fibre (B) Sarcomere
(C) Myofibril (D) Sarcosome

34. 33. Match the column and find out the correct answer :
(A) a = ii, b = iv, c = I, d = iii (B) a = iii, b = iv, c = ii, d = i
(C) a = iii, b = iv, c = i, d = ii (D) a = iii, b = i, c = iv, d = ii
Column-I Column-II
a Area of only thick filaments (i) A-band
b Separates the sarcomeres from each
other
(ii) I-band
c Middle are in the sarcomere where
thick and thin filaments are found
(iii) H-zone
d Area in the sarcomere where only thin
filaments are presents
(iv) Z-disc

35. 34. Identify figure A, B, C and find out the correct option of information of
these figures :
(A) A→ Striated and involuntary muscle
B→ Do not exhibit any striation and are smooth in appearance
C→ Primarily involved in locomotory actions and changes body
postures.
(B) A → Branching pattern, Striated, Voluntary
B→ Muscle fibre short, Uninucleated, Unbranched
C→ Long, cylindrical, unbranched, Uninucleated muscle fibre.
(C) A→ Associated with the skeletal components of the body
B→ Located in inner wall of hollow visceral organs
C→ Found in the heart
(D) A → Found in the heart
B → Nonstriated, voluntary muscles
C→ Associated with the skeletal components of the body.

36. 35. Which muscles are primarily involved in locomotory actions and
changes of body postures?
(A) Cardiac muscles (B) Smooth muscles
(C) Skeletal muscle (D) All of these

37. 36. Actin binding sites are found on :
(A) Actin protein (B) Tropomyosin
(C) Myosin (D) Troponin

38. 37. Which points is incorrect about Myasthenia gravis disease ?
(A) Neuromuscular junction is affected
(B) Auto-immune disorder
(C) Secretion from nerve terminal is reduced
(D) Can lead to fatigue, weakening and paralysis of skeletal muscle

39. 38. Which points are correct with the regarding of Cardiac muscle ?
(i) Have dark and light bands
(ii) Intercalated disc are present
(iii) Similar to smooth muscle in structure
(iv) Muscle fibres are branched, cylindrical
(v) Get fatigued after a long period
(vi) Unstriated and involuntary
(A) i, ii, iii, vi (B) i, ii, iv
(C) iii, iv, v (D) i, iii, v

40. 39. Pick up the odd one in each series and select correct option :
(i) Actin, Myosin, Sarcomere, Troponin
(ii) Fascicles, Tropomyosin, Muscle fibre Myofibril.
(iii) Myosin, Actin, Troponin, Tropomyosin
(iv) ATPase enzyme, ATP binding site, Actin biding site, Myosin
binding site
(A) (B) (C) (D)
(A) Sarcomere Tropomyosin Myosin Myosin binding
(B) Sarcomere Tropomyosin Myosin Actin binding
(C) Troponin Fascicles Actin ATP binding site
(D) Troponin Fascicles Tropomyosin ATP ase enzyme

41. 40. Consider the following four statements (a–d) and select the option
which includes all the correct ones :
(a) Skeletal muscle fibre is a syncytium as the sarcoplasm contains
many nuclei.
(b) In the centre of each “I band” is an elastic fibre called H–line
which bisects it.
(c) In the resting state a subunit of Troponin masks the active
binding sites for myosin on the actin filaments.
(d) The contraction of a muscle fibre takes place by the sliding of the
thick filaments over the thin filaments.
(A) b, c, d (B) b, d
(C) a, c (D) a, c, d

42. 41. Consider the following four statements (a–d) and selection the option
which includes all the correct ones only :
(a) Each organized skeletal muscle is made of a number of muscle
bundles or Fasiculi.
(b) Each muscle fibre has many parallely arranged myofibrils.
(c) Each myofibril contains many serially arranged units called
sarcomere.
(d) Each sarcomere has a central “A”:-band and two half “I” bands.
(A) Statements b, c, d (B) Statements a, b
(C) Statements c, d (D) Statements a, b, c, d

43. 42. Store house of calcium in muscle is :
(A) Sarcomere (B) Sarcosome
(C) Sarcoplasmic reticulum (D) Myofibril

44. 43. Which of the following structures is correctly organized from large to
small ?
(A) Muscle, Muscle fibre, Myofibril, Sarcomere, Filaments
(B) Muscle, Muscle fibre, Sarcomere, Filaments, Myofibril
(C) Muscle, Filaments, Myofibril, Sarcomere, Muscle fibre
(D) Filaments, Myofibril, Sarcomere, Muscle fibre, Muscle

45. 44. Muscle of alimentary canal are mainly :
(A) Striated and Myogenic (B) Striated and Neurogenic
(C) Unstriated and Neurogenic (D) Unstriated and Myogenic

46. 45. Which of the following statements are correct?
(i) Muscle contraction is initiated by a signal sent by CNS a motor
neuron.
(ii) During muscle contraction, isotropic band gets elongated.
(iii) The dark band contains only Myosin filament
(iv) A motor neuron along with the muscle fibres connected to it
constitute a motor unit.
(A) (i) and (ii) are correct (B) (ii) and (iii) are correct
(C) (iii) and (iv) are correct (D) (i) and (iv) are correct

47. 46. ATPase enzyme, needed for muscle contraction is located in :
(A) Troponin (B) Myosin
(C) Actin (D) Tropomyosin

48. 47. Which ions are responsible for muscle contraction?
(A) Ca2+, K+ (B) Na+, K+
(C) Na+, Mg2+ (D) Ca2+, Mg2+

49. 48. Ciliary movement is found in :
(A) Macrophages and leucocytes
(B) Fallopian tube and vasa deferentia
(C) Fallopian tube and Trachea
(D) Tongue and Limbs

50. 49. Which character is not associated with White muscle fibres ?
(A) Less quantity of myoglobin
(B) Number of mitochondria are few
(C) Amount of sarcoplasmic reticulum is low
(D) Depend on anaerobic process for energy

51. 50. Type of movement shown by Paramecium is :
(A) Amoeboid (B) Cilary
(C) Flagellar (D) Muscular