exam qs: kidney excretion

Question 1

The kidneys of a healthy individual filter 178 dm3 day−1 of fluid from the glomeruli into the renal capsules.
However, only 1.5 dm3 day−1 of urine is produced.

What percentage of the filtrate is reabsorbed back into the blood? (1)

A 176.5
B 0.8
C 11.8
D 99.2

Answer 1

D 99.2

Question 2

Patients with kidney failure can be treated in different ways.

Which of the following statements describes a feature of peritoneal dialysis? (1)

1 Urea and mineral ions pass into the tissue fluid.
2 Blood is passed over an artificial membrane to remove toxins.
3 The patient receives immunosuppressant medication.

A 1, 2 and 3
B Only 1 and 2
C Only 2 and 3
D Only 1

Answer 2

D Only 1

Question 3

The hormone hCG can be detected in urine using pregnancy tests.

Which of the following properties of the hormone hCG allows it to be detected in urine? (1)

A hCG is a polar molecule
B hCG has a molecular mass of less than 69,000
C hCG is a polypeptide
D hCG binds to cells using glycoproteins

Answer 3

C hCG is a polypeptide

Question 4

Damage to the hypothalamus results in lower water potential of the blood.

Which of the following, A to D, explains these observations? (1)

A ADH release increases the water potential of blood.
B Mineralocorticoids affect cells in the loop of Henle.
C Fewer water channels are inserted into the cell surface membranes of the collecting duct.
D The anterior pituitary releases hormones into the blood.

Answer 4

C Fewer water channels are inserted into the cell surface membranes of the collecting duct.

(mark scheme also says to allow A)

Question 5

Sodium ions and glucose are both reabsorbed into the blood from proximal convoluted tubules (PCTs)
in the kidney.

A student designed an experiment to investigate the effect of temperature on the rate of glucose
diffusion through dialysis tubing.

State two factors that would need to be controlled in this experiment (2)

Answer 5

• glucose concentration (on both sides on the membrane)
• volume of solution
• length / diameter, of dialysis
  tubing
• type / brand, of dialysis tubing

Question 6

Describe the structural difference between alpha and beta glucose molecules. (1)

Answer 6

alpha glucose: H above ring / OH below ring, on, carbon 1/C1

(annotated diagram allowed)