Question

1. Which of the following statements about insulin is false?

(a) It is a type of extracellular messenger molecule called a paracrine signal

(b) Insulin receptors are present on some but not all cells of the body

(c) When insulin binds to its receptor, it activates a signal transduction pathway inside cells

(d) A cellular response to insulin is the uptake of glucose, this helps to lower blood glucose levels after a meal

(e) Many people have a condition called insulin resistance that predisposes them to diseases like type II diabetes and obesity.

Answer 1

The insulin hormone is produced by the pancreas. It is a type of paracrine signal which acts on a distant target. Since it can't cross the plasma membrane it binds on the receptors on the membrane which results in a signaling cascade. The high level of blood glucose results in the uptake of glucose by insulin. But due to malfunction in the receptor for insulin Type II diabetes and obesity like disease develops.

Since insulin is required by all cells, the receptor for insulin is present on all cells.

The answer is B.