Cambridge O Level Biology · Syllabus 5090 · Coordination and Control
Glucagon
What is Glucagon?
A hormone secreted by the pancreas when the blood glucose concentration falls below the set point. It causes the liver to convert stored glycogen back into glucose and to release that glucose into the blood, so the blood glucose concentration rises towards the set point.
This definition is part of the Coordination and Control chapter in Cambridge O Level Biology.
Common mistakes with Glucagon
- Glycogen, glucagon, glucose. Three words, and in an exam under pressure they blur. Glucose is the sugar dissolved in the blood. Glycogen is the storage carbohydrate made of many glucose molecules, held in the liver. Glucagon is the hormone. Write each one out slowly the first time you use it in an answer.
- Direction check. Insulin goes with high and pushes down. Glucose to glycogen. Out of the blood, into store. If your answer has insulin doing anything that raises blood glucose, you have written glucagon's job under insulin's name.
Questions students ask about Glucagon
What does glucagon do?
Glucagon is released by the pancreas when the blood glucose concentration falls below the set point. It causes the liver to convert stored glycogen into glucose and release that glucose into the blood, so the blood glucose concentration rises back towards the set point.
Last reviewed Syllabus 2026-2028