10 (a) Figure 18 shows two light receptor cells from the human eye - Edexcel - GCSE Biology - Question 10 - 2022 - Paper 1
Question 10
10 (a) Figure 18 shows two light receptor cells from the human eye.
(i) Which part of the eye contains light receptor cells?
A cornea
B iris
C lens
D retina
(ii) ... show full transcript
Worked Solution & Example Answer:10 (a) Figure 18 shows two light receptor cells from the human eye - Edexcel - GCSE Biology - Question 10 - 2022 - Paper 1
Step 1
Which part of the eye contains light receptor cells?
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Answer
The part of the eye that contains light receptor cells is the D retina. The retina houses both rods and cones, which are essential for vision.
Step 2
Name the organelles labelled X.
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Answer
The organelles labelled X are mitochondria. These organelles are responsible for producing energy through respiration.
Step 3
Name the organelle labelled Y.
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The organelle labelled Y is the nucleus. The nucleus contains the chromosomes within the cell.
Step 4
Name cell A.
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Cell A is known as a rod cell. Rods are sensitive to low light levels, facilitating night vision.
Step 5
Describe how the role of light receptor cell B is different from the role of light receptor cell A.
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Light receptor cell B, likely a cone cell, is responsible for color vision and operates best in bright light conditions. In contrast, cell A (the rod cell) is adapted for low light conditions and does not perceive color, focusing instead on brightness and movement.
Step 6
Calculate the time an impulse takes to travel the length of the optic nerve.
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To calculate time, we use the formula:
ext{time} = rac{ ext{distance}}{ ext{speed}}
$$.
Here, the distance is 47 mm (or 0.047 m) and the speed is 75 m/s. Thus, the time is:
ext{time} = rac{0.047 ext{ m}}{75 ext{ m/s}} = 0.00062667 ext{ s} ext{ or approximately } 0.0006 ext{ seconds}.
Step 7
Which part of the brain contains the occipital lobe?
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Answer
The part of the brain that contains the occipital lobe is the A cerebral hemispheres. The occipital lobe is located at the back part of the brain and is primarily responsible for visual processing.
Step 8
State the sense most likely to be affected if the occipital lobe is damaged.
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The sense most likely to be affected if the occipital lobe is damaged is sight. Damage to this area can lead to visual impairments or loss of vision.