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Essential Biochemistry - Muscle (Section 2)

1
Which of the following is NOT an accessory protein of myofilaments?
Answer
(A)
Actin
2
In the 'sliding filament model', the filaments that slide are:
Answer
(C)
Both actin and myosin
3
Which of the following proteins are involved in muscle contraction, except:
Answer
(C)
Myoglobin
4
Which of the following is a source of energy for muscle contraction, primarily used for short bursts of activity?
Answer
(B)
Creatine phosphate
5
Which of the following is a function of myosin?
Answer
(C)
Hydrolyzes ATP
6
The Z-lines is made of the protein:
Answer
(C)
Desmin
7
Which of the following is the most accepted model of muscle contraction?
Answer
(A)
Sliding filament model
8
What specific event directly causes the myosin head to detach from actin?
Answer
(B)
ATP binding to myosin
9
What does ATP do in muscle contraction?
Answer
(D)
All of the above
10
Which of the following happens during the power stroke?
Answer
(C)
Myosin head pulls the actin filament
11
The basic structural unit of a muscle fiber is the:
Answer
(A)
Sarcomere
12
What is the primary function of ATP in muscle contraction?
Answer
(A)
To provide energy for the power stroke
13
What is the role of troponin in muscle contraction?
Answer
(D)
All of the above
14
What is the main function of the sarcoplasmic reticulum (SR) in muscle cells?
Answer
(B)
Store and release calcium ions
15
Which of the following does not change length during muscle contraction?
Answer
(C)
A band
16
The basic contractile unit of striated muscle is the:
Answer
(C)
Sarcomere
17
What is the primary function of the sarcoplasmic reticulum (SR) in muscle cells?
Answer
(C)
Calcium storage
18
The 'power stroke' of muscle contraction is directly driven by:
Answer
(B)
The hydrolysis of ATP
19
Which of the following describes the role of the H zone in a sarcomere?
Answer
(A)
Region containing only thick filaments
20
Which of the following best describes the role of tropomyosin?
Answer
(B)
Covers myosin binding sites on actin
21
Which of the following is the key regulator of muscle contraction?
Answer
(A)
Calcium ions
22
Which molecule directly blocks the binding of myosin to actin?
Answer
(B)
Tropomyosin
23
During muscle contraction, the thick and thin filaments:
Answer
(C)
Overlap each other
24
What is the role of creatine phosphate in muscle contraction?
Answer
(B)
Regenerates ATP
25
The binding of which molecule initiates the cross-bridge cycle?
Answer
(A)
ATP
26
Which muscle type is generally not striated?
Answer
(C)
Smooth muscle