A. | It is initiated by a signal sent by CNS via sensory neuron. |
B. | Neurotransmitter generates action potential in the sarcolemma. |
C. | Increased Ca++ level leads to the binding of calcium with troponin actin filaments. |
D. | Masking of active site for actin is activated. |
E. | Utilising the energy from ATP hydrolysis to form cross bridge. |
1. | Actin and myosin filaments slide over each other to increase the length of the sarcomere. |
2. | Length of A–band does not change. |
3. | I–band increases in length |
4. | The actin filaments slide away from A–band resulting in shortening of sarcomere |
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
1. | binds to troponin to remove the masking of active sites on actin for myosin. |
2. | activates the myosin ATPase by binding to it. |
3. | detaches the myosin head from the actin filament. |
4. | prevents the formation of bonds between the myosin cross bridges and the actin filament. |
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 |
Sliding filament theory can be best explained as:
1. | when myofilaments slide past each other, actin filaments shorten while myosin filament does not shorten |
2. | actin and myosin filaments shorten and slide past each other |
3. | actin and myosin filaments do not shorten but rather slide pass each other |
4. | when myofilaments slide past each other, myosin filaments shorten while actin filaments do not shorten |