Q. Consider the following statements about the functions of Insulin in our body:

1. It prevents absorption of glucose from the blood
2. It facilitates storing of glucose as glycogen
3. It prevents the use of fat for deriving energy

Which of the above statements is / are correct?
Answer: Only 2 & 3
Notes: Insulin activates the absorption of glucose from the blood by the cells of the muscle, liver and fat tissues. It also facilitates the storing of glucose as glycogen in the liver and muscle. Besides this, it prevents the use of fat for deriving energy. Insulin is released in the body in two phases. The first phase involves the rapid release of a large amount of insulin in response to an increased level of glucose in the blood produced from the digestion of food. This high level of insulin induces the cells to absorb glucose from the blood which results in a reduction in the blood glucose level. The second phase refers to the small amount of insulin continuously secreted by the beta cells. This ensures a constant supply of energy. When the blood plasma comes into contact with the liver and muscle cells, the insulin bounded to the beta globulins interact with the receptors (protein molecules) embedded in plasma membrane or cytoplasm of the cells, helping the passage of glucose into the cells. In the absence of insulin, the absorption of glucose gets impaired due to which the body tends to use stored fats to get energy, thereby generating harmful byproducts, ketones. On the other hand, the blood glucose level increases since the body cannot absorb and utilize glucose in the absence of insulin.