5 (a) Motor neurones are found in the nervous system - Edexcel - GCSE Biology Combined Science - Question 5 - 2021 - Paper 1
Question 5
5 (a) Motor neurones are found in the nervous system.
Figure 8 shows a motor neurone.
(i) Draw an arrow on Figure 8 to show the direction of travel of an electrical... show full transcript
Worked Solution & Example Answer:5 (a) Motor neurones are found in the nervous system - Edexcel - GCSE Biology Combined Science - Question 5 - 2021 - Paper 1
Step 1
Draw an arrow on Figure 8 to show the direction of travel of an electrical impulse along the motor neurone.
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Answer
An arrow should be drawn from the dendrites (or cell body) of the motor neurone towards the axon terminal, indicating that the impulse travels from left to right.
Step 2
Name both structure K and structure L.
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Answer
K - myelin (sheath)
L - axon
Step 3
Describe how an impulse passes from the relay neurone to the motor neurone.
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Answer
The process begins when the impulse in the relay neurone triggers the release of a neurotransmitter. This neurotransmitter then diffuses across the synapse, which is the gap between the relay neurone and the motor neurone. Upon reaching the motor neurone, a new impulse is triggered, continuing the signal transmission.
Step 4
Explain the function of a reflex arc.
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Answer
A reflex arc functions as a rapid response mechanism to stimuli, enabling an immediate reaction. It bypasses the brain and directly connects sensory neurones to motor neurones via relay neurones. This process allows for quicker transmission of electrical impulses, hence providing protection from potential harm, such as pulling a hand away from a hot surface.
Step 5
Which is the median result for these students?
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The median result is 210 milliseconds.
Step 6
Describe how the scientist could compare the reaction times of these students when they respond to red squares turning into yellow squares.
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Answer
The scientist should ensure that each student measures their reaction time using red squares, maintaining all other variables constant, such as the environmental conditions. Repeat the measurements for each student to gather sufficient data, calculate a mean reaction time, and compare the results to analyze any differences influenced by the color change.