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%
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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 |
 84%
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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%
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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 |
 54%
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Consider the given two statements:
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%
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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 |
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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 |
 62%
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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 |
 68%
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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 |
 73%
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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 |
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