During muscle contraction, the part that does not get shortened in length is labeled as the letter:
1. A | 2. B |
3. C | 4. D |
What happens during the contraction of a skeletal muscle fiber?
1. | The myosin filaments stay the same size but the actin filaments shorten |
2. | The sarcomeres shorten |
3. | The actin filaments stay the same size but the myosin filaments shorten |
4. | Both actin and myosin filaments shorten |
I: | Repeated activation of muscles can lead to fatigue. |
II: | Repeated activation of muscles can lead to accumulation of lactic acid. |
Assertion (A): | Shortening of myofilaments leads to the shortening of the muscle. |
Reason (R): | Only the actin myofilaments shorten while the length of the myosin myofilaments remains the same during the muscle shortening. |
In the light of the above statements choose the correct answer from the options given below:
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. |