1 Blood is filtered in the kidney to remove unwanted substances - Edexcel - GCSE Biology - Question 1 - 2018 - Paper 1
Question 1
1 Blood is filtered in the kidney to remove unwanted substances.
Figure 1 shows part of a nephron.
Figure 1
(a) Name the structures labelled P and Q.
P
Q
Worked Solution & Example Answer:1 Blood is filtered in the kidney to remove unwanted substances - Edexcel - GCSE Biology - Question 1 - 2018 - Paper 1
Step 1
Name the structures labelled P
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Answer
P is the glomerulus. This structure is involved in the filtration of blood, where unwanted substances are removed.
Step 2
Name the structures labelled Q
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Answer
Q is Bowman's capsule. It encases the glomerulus and collects the filtrate that is produced during the filtration process.
Step 3
1(b)(i) Calculate the total concentration
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Answer
To find the total concentration, we perform the following substitution:
4.5×106−8.0×103
Evaluating this gives:
4.5×106−0.008×106=4.492×106
Thus, the answer is 4.492 million.
Step 4
1(b)(ii) Explain why certain substances are not filtered
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Answer
Red blood cells, white blood cells, and proteins are not present in the filtrate because:
They are too large to pass through the membrane into the nephron.
On the other hand, glucose is found in the filtrate because it is small enough to pass through the membrane into the nephron.
Step 5
1(c) Name another hormone involved
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Answer
Another hormone involved in this process is ADH (Anti-diuretic hormone), which helps regulate water balance in the body.
