Which of the following is not a function of the skeletal system?
1. Production of erythrocytes
2. Storage of minerals
3. Production of body heat
4. Locomotion
| 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. |
| Assertion (A): | After death, the body muscles get stiff as a state of partial contraction of muscles. |
| Reason (R): | Attachment of the myosin head to unexposed sites on actin can take place partially. |
| 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. | (A) is False but (R) is True. |
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| 1. | (a) Skeletal - Triceps (b) Smooth - Stomach (c) Cardiac - Heart |
2. | (a) Skeletal - Biceps (b) Involuntary - Intestine (c) Smooth - Heart |
| 3. | (a) Involuntary - Nose tip (b) Skeletal - Bone (c) Cardiac - Heart |
4. | (a) Smooth - Toes (b) Skeletal - Legs (c) Cardiac - Heart |
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) and (e) only
2. (b), (d), (e) and (a) only
3. (a), (c), (d) and (e) only
4. (a), (b), (c) and (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 |
Stimulation of a muscle fiber by a motor neuron occurs at:
1. the neuromuscular junction
2. the transverse tubules
3. the myofibril
4. the sarcoplasmic reticulum
| 1. | Sarcomere does not shorten | 2. | A band remains the same |
| 3. | A, H and I bands shorten | 4. | Actin filaments shorten |
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 |
| 1. | Smooth muscle | 2. | Intercalated discs |
| 3. | Cartilage | 4. | Areolar tissue |