Figure 19 shows a chart used by opticians to test a person’s vision - Edexcel - GCSE Biology - Question 10 - 2023 - Paper 1
Question 10
Figure 19 shows a chart used by opticians to test a person’s vision.
The person’s vision is judged by the lowest row of letters they can read.
(a) (i) An optician t... show full transcript
Worked Solution & Example Answer:Figure 19 shows a chart used by opticians to test a person’s vision - Edexcel - GCSE Biology - Question 10 - 2023 - Paper 1
Step 1
An optician tested the eyesight of 240 people. Calculate the number of people who need glasses to correct their vision.
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Answer
To find the number of people who need glasses, first calculate the number of people who could read the normal vision row.
35% of 240 is calculated as:
240×0.35=84
This means 84 people have normal vision. The remaining people who need glasses is:
240−84=156
Therefore, 156 people need glasses to correct their vision.
Step 2
Give one reason why people are short-sighted.
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Answer
One reason why people are short-sighted is that their eyeball may be too long, causing light rays to focus in front of the retina instead of directly on it.
Step 3
Which diagram shows how short-sightedness can be corrected?
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Answer
The correct diagram is the one that shows a lens diverging the incoming light rays to ensure they focus on the retina, which is typically represented by diagram A.
Step 4
Describe why a person with cataracts would see the image shown in Figure 20.
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Answer
A person with cataracts has a cloudy lens in their eye, which scatters light rays and makes images appear blurry. This condition affects their ability to see clearly, resulting in the distorted or unclear image shown in Figure 20.
Step 5
State the treatment for cataracts.
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Answer
The treatment for cataracts is usually surgical, where the cloudy lens is removed and replaced with an artificial lens.
Step 6
Which region of the brain is labelled structure X?
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Answer
Structure X is labelled as the cerebellum (Option A).
Step 7
Describe how messages are sent from the brain to muscles.
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Answer
Messages are sent from the brain to muscles via motor neurons. When the brain decides to initiate a movement, it sends a signal down the spinal cord through motor pathways, leading to the appropriate muscles. These neurons release neurotransmitters at the neuromuscular junction, causing muscle contraction.
