Which of the following muscles act involuntarily?
(a) Striated muscles
(b) Smooth muscles
(c) Cardiac muscles
(d) Skeletal muscles
1. (a) & (b)
2. (b) & (c)
3. (c) & (d)
4. (a) & (d)
| 1. | Skeletal muscle |
| 2. | Cardiac muscle |
| 3. | Smooth muscle |
| 4. | Elastic muscle |
| Assertion (A): | Skeletal muscles are also known as striated muscles |
| Reason (R): | Skeletal muscles have striped appearance under electron microscope due to the presence of alternate light and dark bands |
| 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. |
| Statement I: | Each actin (thin) filament is made of two ‘F’ (filamentous) actins helically wound to each other. |
| Statement II: | Each ‘F’ actin is a polymer of monomeric ‘G’ (Globular) actins. |
| 1. | Statement I is correct; Statement II is correct |
| 2. | Statement I is correct; Statement II is incorrect |
| 3. | Statement I is incorrect; Statement II is correct |
| 4. | Statement I is incorrect; Statement II is incorrect |
| Assertion (A): | Skeletal muscle fibres appear striated. |
| Reason (R): | They possess light and dark bands of contractile proteins actin and myosin. |
| 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. |
| Statement A: | The muscle bundles are bound together by a common collagenous sheath of connective tissue called fascia. |
| Statement B: | Muscle fibre is a syncytium as the sarcoplasm contains many nuclei. |
| 1. | Both statements A and B are correct |
| 2. | Both statements A and B are incorrect |
| 3. | Only statement A is incorrect |
| 4. | Only statement A is correct |
| 1. | fascia | 2. | perimysium |
| 3. | endomysium | 4. | sarcolemma |
| 1. | It is mesodermal in origin |
| 2. | 40-50% of body weight is formed by it |
| 3. | They have properties like excitability and contractibility |
| 4. | They are classified on the basis of reception of a type of stimulus |
Which one of the following statement is incorrect?
| 1. | Heart muscles are striated and involuntary |
| 2. | The muscles of hands and legs are striated and voluntary |
| 3. | The muscles located in the inner walls of alimentary canal are striated and involuntary |
| 4. | Muscles located in the reproductive tracts are unstriated and involuntary |
| Column-A | Column-B | ||
| A. | Myosin | P. | Blocks the active sites on actin filaments in a relaxed muscle |
| B. | Actin | Q. | Binds to troponin, causing the troponin to change shape and move tropomyosin away from the active sites |
| C. | Tropomyosin | R. | Thin filaments that slide past myosin during muscle contraction |
| D. | Calcium Ions | S. | Thick filaments that pull on actin filaments to shorten the muscle |
| A | B | C | D | |
| 1. | S | R | P | Q |
| 2. | S | R | Q | P |
| 3. | P | Q | R | S |
| 4. | P | Q | S | R |