Q. No.1. Myosin head
2. Myosin tail
3. Troponin T
4. Tropomyosin
Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction:
| 1. | Calcium | 2. | Magnesium |
| 3. | Sodium | 4. | Potassium |
1. Actin
2. Tropomyosin
3. Troponin
4. Myosin
Contractile fibrils of muscles are called:
(1) Neurofibrils
(2) Collagen fibres
(3) Myofibrils
(4) Yellow fibres
| Statement I: | Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. |
| Statement II: | Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. |
2. Statement I is correct; Statement II is incorrect
3. Statement I is incorrect; Statement II is correct
4. Statement I is incorrect; Statement II is incorrect
1. HMM=Tail + short arm
2. LMM = Tail + Head
3. HMM = Head + short arm
4. LMM = Head
Reason (R): The light band on myofibril is isotropic band.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. Both (A) and (R) are false
The monomeric protein which polymerises to form myosin is
1. Actin
2. Meromyosin
3. Tropomyosin
4. Troponin
During muscular contraction, which of the following events occur?
(a) 'H' zone disappears
(b) 'A' band widens
(c) 'I' band reduces in width
(d) Myosin hydrolyzes ATP, releasing the ADP and Pi
(e) Z-lines attached to actins are pulled inwards
Choose the correct answer from the options given below.
1. (b), (c), (d), (e) only
2. (b), (d), (e), (a) only
3. (a), (c), (d), (e) only
4. (a), (b), (c), (d) only
In the given diagram, identify A, B, C:
| (A) | (B) | (C) | |
| 1. | Tropomyosin | F-Actin | Troponin |
| 2. | Troponin | Tropomyosin | F-Actin |
| 3. | F-Actin | Tropomyosin | Troponin |
| 4. | Tropomyosin | Troponin | F-Actin |
© 2026 GoodEd Technologies Pvt. Ltd.