Identify the correct statement regarding the comparison of skeletal and smooth muscle:
1. Nervous stimulation of smooth muscle is always excitatory, whereas nervous stimulation of skeletal muscle may be excitatory or inhibitory.
2. The contractile activity of smooth muscle may be affected by hormones, whereas the contractile activity of the skeletal muscle is not.
3. Both ANS and somatic neural systems innervate smooth muscle, whereas skeletal muscle may be innervated by the somatic motor system only.
4. The calcium-binding protein in smooth muscle is troponin whereas in skeletal muscle, it is tropomyosin.
The critical event for the contraction of striated muscles would be that calcium ions:
1. | are released from troponin C |
2. | bind to tropomyosin |
3. | bind to troponin |
4. | are taken up by the sarcoplasmic reticulum |
Identify the correct statement regarding the use of ATP in muscle contraction:
1. ATP cannot be directly used for muscle contraction.
2. ATP is not required for muscle relaxation.
3. When ATP is hydrolyzed, the conformation of myosin is changed.
4. Once the cross-bridge is formed, the hydrolysis of ATP initiates the power stroke.
Identify the correct statement regarding human ribs:
1. The true ribs attach directly to the sternum with costal cartilage.
2. Floating ribs do not have any attachments.
3. The human ribs are tricephalic.
4. Vertebrochondral ribs are classified as true ribs.
Name the ion responsible for the unmasking of active sites for myosin for cross-bridge activity during muscle contraction.
1. | Calcium | 2. | Magnesium |
3. | Sodium | 4. | Potassium |
The globular head of the myosin filament has active site/s for binding to:
I. ATP
II. Active site on actin filament
III. Calcium
1. | Only I | 2. | Only I and II |
3. | Only II and III | 4. | I, II and III |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
The phosphogen that helps the regeneration of ATP from ADP during muscle contraction in vertebrates is
1. | ADP | 2. | Inosital phosphate |
3. | Arginine phosphate | 4. | Creatine phosphate |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Smooth muscle is fundamentally different from skeletal muscle and cardiac muscle. |
Reason (R): | Smooth muscle is an involuntary non-striated muscle. |
In the light of the above statements choose the correct answer from the options given below:
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. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Within the A-band of a sarcomere is a paler region called the H-zone. |
Reason (R): | H-zone is the zone of the thin myofilaments in the center of the A band. |
In the light of the above statements choose the correct answer from the options given below:
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. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Hydrolysis of ATP by myosin head is critical for the cross bridge formation. |
Reason (R): | Myosin head has ATPase activity dependent on magnesium ions |
In the light of the above statements choose the correct answer from the options given below:
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. |