Engineering Questions with Answers - Multiple Choice Questions

MCQs on Cell Motility – Muscle Contractility

1 - Question

Muscle cells are ___________
a) irregularly shaped
b) cylindrically shaped
c) extremely fragile
d) extremely labile

View Answer

Answer: b
Explanation: Muscle cells are cylindrically shaped, 10 to 100 μm thick and 100 mm long. Due to these distinctive properties a skeletal muscle cell is called muscle fiber.




2 - Question

Muscle cells are formed from the fusion of ___________
a) myoblasts
b) fibroblasts
c) mast cells
d) neurons

View Answer

Answer: a
Explanation: Muscle fibers contain many nuclei because each muscle fiber is a product of fusion of myoblasts. Myoblasts are premuscle cells in the embryo.




3 - Question

The striated appearance of muscle fibers is due to _______________
a) nucleus
b) sacromeres
c) sarcoma
d) myoblasts

View Answer

Answer: b
Explanation: Hundreds of thin, cylindrical strands called myofibrils. Each myofibril contains repeating contractile units, called sarcomeres. The sarcomeres exhibit a banding pattern giving the muscle cells a striated appearance.




4 - Question

All skeletal muscles operate by _______________
a) shortening
b) exciting
c) firing
d) contracting

View Answer

Answer: a
Explanation: The skeletal muscles operate by the process of shortening, sacromeres are the units of shortening whose combined decrease in length account for decrease in length of entire muscle.




5 - Question

________ of the sacromere remains unaffected during the muscle contraction.
a) H zone
b) A band
c) I band
d) H band

View Answer

Answer: b
Explanation: The A band of sacromeres remains constant in length whereas H and I bands decrease in length and disappear altogether.




6 - Question

The “Sliding filament model of muscle contraction” was proposed in the year ____________
a) 1954
b) 1964
c) 1974
d) 1984

View Answer

Answer: a
Explanation: The “Sliding filament model of muscle contraction” was proposed in the year 1954 by two groups of British investigators, Andrew Huxley and Rolf Niedergerke, and Hugh Huxley and Jean Hanson.




7 - Question

According to “Sliding filament model of muscle contraction”, shortening of sacromeres results from sliding of the filaments.
a) True
b) False

View Answer

Answer: a
Explanation: According to the “Sliding filament model of muscle contraction” shortening of sacromeres results from sliding of the filaments one over the other.




8 - Question

Which of the following proteins are not found in muscle fibres?
a) keratin
b) actin
c) troponin
d) tropomyosin

View Answer

Answer: a
Explanation: The muscles fibers consist of actin, troponin and tropomyosin. All these aforementioned are motor proteins.




9 - Question

Each tropomyosin is associated with _______ subunits of actin subunits.
a) 2
b) 3
c) 7
d) 9

View Answer

Answer: c
Explanation: Tropomyosin is a 40 nm long elongated molecule and it fits into the grooves of within the thin filaments. Each tropomyosin is associated with 7 actin subunits.




10 - Question

. Troponin is composed of _____ subunits.
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: c
Explanation: Troponin is a globular protein found in muscle fibers. It consists of three subunits, each having a distinctive role in the overall function of the molecule.




11 - Question

Titin is the largest protein discovered till date.
a) True
b) False

View Answer

Answer: a
Explanation: Titin is an abundant protein found in skeletal muscles and is the largest protein discovered in any organism. The gene encoding for titin contains approximately 38000 amino acids.




12 - Question

. Which of the following prevents sacromeres from pulling apart during muscle stretching?
a) titin
b) vimentin
c) myosin
d) actin

View Answer

Answer: a
Explanation: Titin prevents sacromeres from pulling apart during muscle stretching and maintains myosin filaments in their proper position.

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