Explain why the estimate of glucose concentration achieved by this method is only ‘semi-quantitative’.
One of the two enzymes immobilised in the cellulose pad on the test strip is glucose oxidase, which catalyses the following reaction: $\text{glucose} + \text{oxygen} \rightarrow \text{gluconic acid} + \text{hydrogen peroxide}$. This reaction does not produce the colour shown by the chromogen. That colour change is brought about by the second immobilised enzyme in the pad.
State the name of the second immobilised enzyme in the pad.
Explain how the reaction catalysed by this enzyme causes the chromogen to change colour.
A layer of cellulose acetate covers the cellulose pad on the test strip; it is permeable to glucose molecules but not to larger molecules. Suggest why the cellulose acetate layer is there.
Two young men, subjects A and B, each received a standardised glucose dose after fasting. Their blood glucose concentrations were measured immediately and then at $30$ minute intervals over two hours. Urine samples from each subject were collected and tested at the same time points. The colour change on each test strip was compared with the colour chart and recorded as -, +, ++ or +++. The findings are shown in Fig. 2.2.
Using Fig. 2.2, explain why the blood glucose concentrations of A and B differ.
State what is meant by the term ‘renal threshold’.
Describe the renal events after ultrafiltration that lead to the rising amount of glucose in B’s urine.
Using Fig. 2.2, explain why the blood glucose concentrations of A and B differ.
State what is meant by the term ‘renal threshold’.
Describe the kidney events after ultrafiltration that lead to the increasing amount of glucose in B’s urine.