Essential Biochemistry - Muscle (Section 1)
1
The primary components of thin filaments include which of the following?
Answer(C)
Actin, tropomyosin and troponin
2
The following proteins are involved in muscle contraction, except:
3
Which of the following is true for sarcomere?
4
Which of the following does not change length during muscle contraction?
5
Which of the following acts as source of energy in muscle contraction?
6
Muscle tissue is responsible for:
7
The main function of the H-zone is to:
8
Which of the following acts in source of energy in muscle contraction?
9
The thick filament consists of the protein:
10
Which of the following is the main function of the H-zone?
Answer(A)
Contains the myosin filaments
11
What is the function of the M-line?
12
The immediate source of energy for muscle contraction is:
13
The contractile protein in muscle fiber is:
14
Which of the following is a function of the Z-lines?
Answer(B)
Anchoring the thin filaments
15
Which of the following is the correct sequence of events in the cross-bridge cycle?
Answer(A)
ATP binds, cross-bridge, power stroke, ADP release
16
The process by which muscle cells create the energy necessary for contraction is:
17
What molecule is directly responsible for the power stroke?
18
Which of the following structures primarily contains actin?
19
Which of the following describes the arrangement of myofilaments in striated muscle?
20
Which of the following is true for sarcomere?
21
The basic functional unit of a skeletal muscle is:
22
Which of the following describes the events occurring during muscle contraction?
23
Which event occurs FIRST in muscle contraction?
Answer(B)
Calcium binds to troponin
24
In the sliding filament theory of muscle contraction, what happens to the actin and myosin filaments?
Answer(C)
They slide past each other
25
Which protein is directly involved in blocking the myosin-binding sites on actin?
26
In the resting state, the tropomyosin molecules lie:
Answer(A)
On top of the active sites of the actin strands
27
Which of the following statements best describes the role of the M-line in a sarcomere?
Answer(B)
It anchors the thick filaments
28
Which of the following is the main component of the thin filament?
29
Actin is a polymer of globular-shaped subunit called:
30
The site where a motor neuron communicates with a muscle fiber is called:
31
Which of these is the end product of the hydrolysis of ATP during muscle contraction?
32
Which molecule directly covers the myosin-binding sites on actin, preventing the cross-bridge formation in a relaxed muscle?
33
Where are the myosin heads located?
34
Which protein binds to calcium ions during muscle contraction?
35
What is the role of troponin?
Answer(A)
Regulating muscle contraction
36
The cells of skeletal muscle are cylindrical in shape and are commonly called:
37
What is the name of the protein that makes up thick filaments?
38
Which structure is the functional unit of the muscle fiber?
39
Which of the following is the correct order of events during muscle contraction?
Answer(D)
ATP binds to myosin, release of ADP, cross-bridge formation, power stroke
40
Where does the energy for the power stroke come from?
41
What is the primary fuel source used in muscle contraction?
42
Which ion is essential for initiating muscle contraction?
43
What regulatory proteins are involved in muscle contraction?
44
During muscle contraction, which of the following bands/zones decreases in length?
45
The energy for muscle contraction is directly provided by:
46
The central region of the A band is less dense than the rest of the band, and is called:
47
The primary components of thin filaments include which of the following?
Answer(C)
Actin, tropomyosin and troponin
48
What is the role of calcium ions in muscle contraction?
49
Which of the following is the primary protein found in the thick filaments?
50
The thin filament consists of the protein:
Answer(D)
Both Actin and Tropomyosin
