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 |
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
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. | 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. |
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. |