- 1(current)
Q. No.As the distance from Z line to Z line decreases, which bands shorten in a sarcomere?
| 1. | the I band and H band | 2. | the I band and A band |
| 3. | the A band and H band | 4. | all bands shorten |
What protein is arranged along the length of actin filaments and is involved in regulation of skeletal muscle contraction?
| 1. | Troponin | 2. | Calmodulin |
| 3. | Tropomyosin | 4. | Light meromyosin |
During relaxation of a skeletal muscle:
| 1. | Calcium ions that are bound to troponin C now bind to troponin A |
| 2. | Cross bridge formation between myosin head and actin takes place |
| 3. | The A band of the sarcomere lengthens |
| 4. | Calcium ions are pumped back to the sarcoplasmic cisternae |
During muscle contraction, when the myosin head releases ADP and iP it:
1. forms cross bridge with actin
2. pulls actin towards M-line
3. goes back to its relaxed state
4. gets detached from the cross bridge
Which of the following masks the active sites on actin when a skeletal muscle is relaxed?
| 1. | Tropomyosin | 2. | Troponin |
| 3. | Calmodulin | 4. | Ubiquitin |
During muscle contraction, the event shown in the following diagram describes:
1. cross bridge detachment
2. the power stroke or working stroke
3. cross bridge formation
4. cocking of myosin head
Cross bridge formation during muscle contraction involves:
| 1. | troponin and actin | 2. | tropomyosin and myosin |
| 3. | myosin and troponin | 4. | myosin and actin |
| I: | Sliding or rotation | A |
| II: | Breaking of cross bridge | B |
| III: | Formation of cross bridge | C |
| I | II | III | |
| 1. | B | A | C |
| 2. | B | C | A |
| 3. | A | B | C |
| 4. | C | A | B |
Arrange the following events in correct chronological order:
| a: | acetylcholine hydrolyses into acetate and choline |
| b: | acetylcholine diffuses across the synaptic cleft |
| c: | Impulse reaches the terminal endings of the motor neuron |
| d: | acetylcholine binds to its receptor on motor end plate |
| e: | sarcolemma gets depolarized |
| 1. | b, c, d, a, e | 2. | c, b, d, e, a |
| 3. | c, d, b, a, e | 4. | d, e, b, a, c |
- 1(current)
Q. No.
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