Question Constellation Sign up for free AQA · GCSE · Biology · Higher
Kidney filtration and selective reabsorption
The kidneys have an important role in homeostasis. Describe what happens to glucose, protein and urea in the kidneys.
Write your answer first. You can study the marking guidance whenever you need it.
Study the marking See what earns credit and compare it with a full-mark answer.
Marking points
- 1 States that glucose and urea are filtered from the blood.
- 2 States that protein is not filtered from the blood.
- 3 States that all glucose is reabsorbed into the blood.
- 4 States that urea is mostly not reabsorbed and leaves in urine.
Full-mark answer
Glucose and urea are filtered out of the blood, but proteins remain in the blood because they are not filtered. All the glucose is selectively reabsorbed into the blood, whereas most urea is not reabsorbed and leaves the body in urine.
Why this answer loses marks
The kidneys filter out glucose, protein and urea and remove them all in urine.
This treats all three substances alike; distinguish what is filtered, retained, reabsorbed and excreted.