Biology 9700 · AS & A Level · Homeostasis in mammals
Homeostasis in mammals — practice question
Phosphoinositide 3-kinase (PI3K) and protein kinase B(PKB) are enzymes that help control blood glucose concentration. Fig. 6.1 illustrates a cell-signalling pathway in a muscle cell involving insulin, PI3K and PKB.
(a)[4]
Type 2 diabetes mellitus is a widespread disease. In some people with type 2 diabetes, the concentration of PI3K in muscle cells is low and they are unable to keep blood glucose concentration within normal limits.
With reference to Fig. 6.1, suggest why a low concentration of PI3K can lead to type 2 diabetes.
(b)[7]
Describe how a biosensor may be used to determine blood glucose concentration.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Less/no activation of PKB” …