1.1. Extended only

Table 1 shows the concentration of different substances in blood plasma, filtrate entering the proximal convoluted tubule and urine.

Table 1

Explain the difference in concentration of protein in the blood plasma and filtrate.

1.2. Extended only

Under normal circumstances there should be no glucose present in urine.

(i)

Explain the reason for this.

[2]

(ii)

Suggest an explanation for the diagnosis that a doctor could make if glucose was present in the urine.

[2]

1.3. Extended only

Fig. 1 shows one of the cells found in the proximal convoluted tubule of the nephron.

Fig. 1

Explain the presence of structure A in Fig. 1.

1.4. Extended only

The concentration of substance X in different parts of the urinary system is shown in Table 1 at part (a).

(i)

Identify whether substance X can be considered a waste product or a useful substance to the body.

[1]

(ii)

Use the information in Table 1 to explain your answer at part (i).

[2]