1.1. Figure 1 shows the human urinary system.

Figure 1

Urine is made by removing water, urea and salts from the blood.

Use the letter X to label where urine is made.

1.2. Which substance is converted to urea in the liver?

1.3. A patient cannot remove enough urea from the blood when making urine.

Figure 2 shows a dialysis machine attached to the arm of this patient.

Their blood is pumped out of their arm, passed through the dialysis machine, and then put back into the patient.

Figure 2

(i) Describe what happens to urea as the blood passes through the dialysis machine.

(2)

(ii) Two patients need to have dialysis treatment.

Patient A needs this treatment three times a week.

Patient B needs this treatment once a week.

Give one reason why patient B needs dialysis treatment less often than patient A.

(1)

1.4. Describe how to test for glucose in the dialysis fluid.

1.5. Urease is an enzyme that breaks down urea into smaller molecules.

Explain why urease will not break down starch into smaller molecules.