Part I — Blood, Skeletal Muscle Cells, and Glucose Uptake
1. Why does glucose uptake by a skeletal muscle cell require a transporter such as GLUT4? In other words, why isn’t simple diffusion possible?
2. What stimulates the insertion of GLUT4s into the sarcolemma?
3. The existence of GLUT4s in the sarcolemma does not guarantee glucose uptake into the cell. Why? What else is required?
4. Exercise helps reduce blood glucose levels in people, even if they are insulin resistant and thus their cells can no longer respond to insulin efficiently. How is this possible?
