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
Calculate the number of people who need glasses to correct their vision.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
To find the number of people who need glasses, first calculate the number of people who can see normally. 35% of 240 people can read the normal vision row:
0.35×240=84
Now, subtract this from the total number of people:
240−84=156
Thus, 156 people need glasses to correct their vision.
Step 2
Give one reason why people are short-sighted.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
One reason why people are short-sighted (myopic) is that their eyes may be too long, causing light to focus in front of the retina instead of directly on it, leading to blurred distance vision.
Step 3
Which diagram shows how short-sightedness can be corrected?
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The diagram that shows how short-sightedness can be corrected is Diagram B, which typically illustrates the use of a diverging lens that helps move the focal point back onto the retina.
Step 4
Describe why a person with cataracts would see the image shown in Figure 20.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A person with cataracts would see a blurred image due to the clouding of the lens in the eye. This condition scatters light entering the eye, thereby reducing clarity and sharpness of vision, making it difficult to distinguish between different letters.
Step 5
State the treatment for cataracts.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The treatment for cataracts typically involves surgical removal of the cloudy lens, which is often replaced with an artificial intraocular lens.
Step 6
Which region of the brain is labelled structure X?
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The region of the brain labelled structure X is B - cerebral hemisphere.
Step 7
Describe how messages are sent from the brain to muscles.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Messages are sent from the brain to muscles via motor neurons. When a stimulus is received, the brain generates electrical impulses that travel down the spinal cord and through the peripheral nerves. These impulses reach the muscle fibers, leading to muscle contraction and movement.
