Q. No.What protein is arranged along the length of actin filaments and is involved in regulation of skeletal muscle contraction?
| 1. | Troponin | 2. | Calmodulin |
| 3. | Tropomyosin | 4. | Light meromyosin |
Subtopic: Sliding Filament Theory |
64%
Level 2: 60%+
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Which of the following masks the active sites on actin when a skeletal muscle is relaxed?
| 1. | Tropomyosin | 2. | Troponin |
| 3. | Calmodulin | 4. | Ubiquitin |
Subtopic: Sliding Filament Theory | Energy for Muscle Contraction |
86%
Level 1: 80%+
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Contraction of a skeletal muscle fibre takes place by:
| 1. | shortening of both actin and myosin myofilaments |
| 2. | shortening of actin and lengthening of myosin myofilaments |
| 3. | the sliding of the thin filaments over the thick filaments |
| 4. | the sliding of the thick filaments over the thin filaments |
Subtopic: Sliding Filament Theory |
92%
Level 1: 80%+
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A motor unit is composed of:
| 1. | a motor neuron and all of the skeletal muscle fibers innervated by the neuron's axon terminals. |
| 2. | all motor neurons and all of the skeletal muscle fibers innervated by them in a muscle. |
| 3. | a motor neuron and one skeletal muscle fiber innervated by the neuron. |
| 4. | a motor neuron and a sensory neuron. |
Subtopic: Sliding Filament Theory | Muscle Contraction: Other Considerations |
57%
Level 3: 35%-60%
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Consider the given two statements:
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
| Statement I: | The junction between a motor neuron and the sarcolemma of the muscle fibre is called the neuromuscular junction. |
| Statement II: | A neural signal reaching the neuromuscular junction releases a neurotransmitter, Acetyl choline, which generates an action potential in the sarcolemma. |
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
Subtopic: Skeletal Muscle: Sarcomere | Excitation Contraction Coupling II | Sliding Filament Theory |
94%
Level 1: 80%+
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The neurotransmitter released by the motor neurons at the neuromuscular junction is:
| 1. | Acetylcholine | 2. | Noradrenaline |
| 3. | GABA | 4. | Adrenaline |
Subtopic: Sliding Filament Theory |
98%
Level 1: 80%+
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Calcium released into the sarcoplasm during muscle contraction:
| 1. | binds to the actin and myosin and makes them work together. |
| 2. | breaks apart ATP to ADP and P. |
| 3. | removes the tropomyosin block. |
| 4. | causes the release of acetylcholine. |
Subtopic: Sliding Filament Theory |
63%
Level 2: 60%+
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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 |
Subtopic: Sliding Filament Theory |
73%
Level 2: 60%+
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To form a cross bridge, during muscle contraction:
| 1. | the myosin head binds to the exposed active sites on actin utilising the energy from ATP hydrolysis |
| 2. | the myosin head binds to the exposed active sites on actin and then the ATP binds to its site on myosin head |
| 3. | the actin binds to the exposed active sites on myosin head utilising the energy from ATP hydrolysis |
| 4. | the actin binds to the exposed active sites on myosin head and then the ATP binds to its site on actin |
Subtopic: Sliding Filament Theory |
72%
Level 2: 60%+
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During muscle contraction, when the myosin head releases ADP and iP it:
1. forms cross bridge with actin
2. pulls actin towards M-line
3. goes back to its relaxed state
4. gets detached from the cross bridge
Subtopic: Sliding Filament Theory | Energy for Muscle Contraction |
Level 3: 35%-60%
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