Question

Some glucose transport molecules are controlled by levels of insulin. When insulin binds to a specific _____, the signal is relayed to a(n) _____, which then controls gene expression.

a) Gene, enzyme
b) Receptor, transporter
c) Protein, promoter
d) Hormone, substrate

Answer 1

Insulin binds to the insulin receptor on cell membranes, which triggers a series of events leading to the translocation of the GLUT4 transporter to the cell surface, thus promoting glucose uptake into the cells.

Step-by-step explanation:

When insulin binds to a specific receptor, the signal is relayed to a protein, which then controls gene expression. The correct answer to the student's question is b) Receptor, transporter.

Insulin initiates its action by binding to the insulin receptor on the cell membrane. This binding activates a tyrosine kinase, which then phosphorylates various proteins, including a substrate called IRS-1 or Insulin Receptor Substrate-1. This phosphorylation triggers a cascade of events leading to the translocation of the GLUT4 transporter to the cell membrane, increasing glucose uptake into cells. This mechanism is critical for regulating blood glucose levels. In diabetic individuals, this process can be compromised, leading to elevated blood glucose levels and the potential for glucose to be excreted in the urine.