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When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob - AQA - A-Level Biology - Question 1 - 2017 - Paper 3
Question 1
When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob. 1. The arrival of the nerve impulse lead... show full transcript
Worked Solution & Example Answer:When a nerve impulse arrives at a synapse, it causes the release of neurotransmitter from vesicles in the presynaptic knob - AQA - A-Level Biology - Question 1 - 2017 - Paper 3
Step 1
0 1 . 2 Use your knowledge of how myosin and actin interact to suggest how the myosin molecule moves the mitochondrion towards the presynaptic membrane.
Answer
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Myosin head attaches to actin filaments and bends, performing a power stroke.
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This action pulls the mitochondrion along the actin filament towards the presynaptic membrane, effectively moving it closer to where neurotransmitter release occurs.
Step 2
0 1 . 3 Suggest and explain one advantage of the movement of mitochondria towards the synapse.
Answer
- The movement of mitochondria provides additional ATP, which is crucial for energy supply, enabling the active transport of ions needed for the recycling or re-synthesis of neurotransmitters. This enhances the efficiency of neurotransmission during nerve impulses.