During periods of fasting, blood glucose levels drop, triggering the release of glucagon from α\alphaα-cells in the islets of Langerhans. Which of the following describes the correct intracellular cascade initiated by glucagon in liver cells to elevate blood glucose?
Glucagon binds to intracellular receptors, activating tyrosine kinase to convert cAMP into ATP. ATP activates protein kinase A, promoting glycogenesis and gluconeogenesis.
Glucagon binds to transmembrane receptors, activating tyrosine kinase to convert ATP into cyclic AMP (cAMP). cAMP activates protein phosphorylase, promoting glycogenesis and glycogenolysis.
Glucagon binds to transmembrane receptors, activating adenylate cyclase to convert ATP into cyclic AMP (cAMP). cAMP activates protein kinase A, promoting glycogenolysis and gluconeogenesis.
Glucagon binds to intracellular receptors, activating adenylate cyclase to convert cAMP into ATP. ATP activates glycogen phosphorylase, promoting glycogenolysis and glycogenesis.
Practise OCR GCSE Biology Maintaining internal environments with exam-style questions for Foundation and Higher tier. 53 questions, matched to the OCR GCSE Biology (J247) specification and written in the written papers style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.