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Describe how ultrafiltration occurs in a glomerulus - AQA - A-Level Biology - Question 1 - 2019 - Paper 3
Question 1
Describe how ultrafiltration occurs in a glomerulus. High blood hydrostatic pressure forces water, glucose, ions, and urea out of the blood through the capillary wa... show full transcript
Worked Solution & Example Answer:Describe how ultrafiltration occurs in a glomerulus - AQA - A-Level Biology - Question 1 - 2019 - Paper 3
Step 1
Describe how ultrafiltration occurs in a glomerulus.
Answer
Ultrafiltration in a glomerulus occurs due to high blood hydrostatic pressure which forces water and small solutes, such as glucose, ions, and urea, through the capillary walls. The fenestrations in the capillaries and the podocytes create a filtration barrier that allows these substances to enter the Bowman’s capsule while preventing larger molecules, such as proteins, from passing through.
Step 2
Step 3
Calculate the mean length of the loop of Henle in an organism that produces urine with a concentration of 16.56 arbitrary units.
Answer
To find the mean length of the loop of Henle, we substitute the concentration value into the equation:
Thus, the mean length of the loop of Henle is approximately 17.4 mm.
Step 4
Explain the pattern shown by the results in Figure 1.
Answer
The results in Figure 1 show a positive correlation between the thickness of the medulla and the concentration of urine produced. As the thickness of the medulla increases, it allows for greater reabsorption of water due to a higher osmotic gradient. This adaptation results in concentrated urine, which is beneficial for water retention in species living in environments where water is scarce.