A: | Muscle bundles are held together by collagenous connective tissue layer called fascicle. |
B: | Sarcoplasmic reticulum of muscle fibre is a store house of calcium ions. |
C: | Striated appearance of skeletal muscle fibre is due to distribution pattern of actin and myosin proteins. |
D: | M line is considered as functional unit of contraction called sarcomere. |
1. | C and D only | 2. | A, B and C only |
3. | B and C only | 4. | A, C and D only |
Which one of the following pairs of chemical substances, is correctly categorised?
1. | Pepsin and prolactin - Two digestive enzymes secreted in the stomach |
2. | Troponin and myosin - Complex proteins in striated muscles |
3. | Secretin and rhodopsin - Polypeptide hormones |
4. | Calcitonin and thymosin - Thyroid hormones |
ATPase enzyme needed for muscle contraction is located in:
1. Troponin
2. Myosin
3. Actin
4. Actinin
The contractile protein of skeletal muscle involving ATPase activity is:
1. tropomyosin
2. myosin
3. α-actinin
4. troponin
ATPase of the muscle is located in
1. actinin
2. troponin
3. myosin
4. actin
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 |
Which of the following is correct statement ?
1. | Actin and regulatory proteins are located in thin filament. |
2. | Z-lines anchor myosin (thick) filament to the ends of the sarcomere. |
3. | Sarcoplasmic reticulum stores acetylcholine. |
4. | Myosin cross bridges contain calcium binding sites. |