OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What triggers the release of insulin?

1. High levels of glucose in the blood

2. Low body temperature

3. Excessive muscle activity

4. Decreased oxygen levels

The correct answer is: High levels of glucose in the blood

The release of insulin is primarily triggered by high levels of glucose in the blood. When you consume food, particularly carbohydrates, the digestive system breaks these down into glucose, which enters the bloodstream. As blood glucose levels rise, it signals the pancreas to release insulin. Insulin is a hormone that facilitates the uptake of glucose by the cells, enabling them to use it for energy or store it as glycogen in the liver and muscle tissue. This process is vital for regulating blood sugar levels and maintaining overall metabolic balance. The other options do not play a role in triggering insulin release. Low body temperature, excessive muscle activity, and decreased oxygen levels are not direct factors involved in insulin secretion, illustrating the specificity of the body's responses to changes in blood glucose concentration.