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1 (a) Figure 1 shows part of a reflex arc in the spinal cord - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1
Question 1
1 (a) Figure 1 shows part of a reflex arc in the spinal cord. (i) Describe how an impulse passes from the relay neurone to the motor neurone. (ii) Explain the func... show full transcript
Worked Solution & Example Answer:1 (a) Figure 1 shows part of a reflex arc in the spinal cord - Edexcel - GCSE Biology Combined Science - Question 1 - 2021 - Paper 1
Step 1
Describe how an impulse passes from the relay neurone to the motor neurone.
Answer
The process begins when the impulse in the relay neurone triggers the release of a neurotransmitter, which acts as a chemical messenger. This neurotransmitter then diffuses across the synapse, creating a new impulse in the next neurone, which is the motor neurone. As a result, the electrical signal is transmitted efficiently from one neurone to the other.
Step 2
Explain the function of a reflex arc.
Answer
A reflex arc is a neural pathway that bypasses the brain to generate a quick response to stimuli. It allows the body to react without the need for conscious thought, ensuring faster transmission of electrical impulses. This mechanism is crucial for protecting the body from harm by facilitating actions that help avoid dangerous situations, such as quickly pulling away from a hot object.
Step 3
Which is the median result for these students?
Answer
The median reaction time for the students is 215 milliseconds. To find the median, the reaction times should be arranged in ascending order: 200, 210, 215, 225, 245. The median is the middle value in this ordered list, which in this case is 215 milliseconds.