AP BIOLOGY

Detailed explanation-1: -Following a meal, insulin is secreted by the pancreas and engages its receptor on the surface of myocytes and adipocytes, thereby activating the canonical PI3K–AKT pathway. Activation of this pathway is necessary and sufficient to trigger exocytosis of GSVs to the plasma membrane.

Detailed explanation-2: -When glucose in the blood binds to glucose receptors on the beta cell membrane, a signal cascade is initiated inside the cell that results in insulin stored in vesicles in these cells being released into the blood stream. Increased insulin levels cause the uptake of glucose into the cells.

Detailed explanation-3: -Like a key fits into a lock, insulin binds to receptors on the cell’s surface, causing GLUT4 molecules to come to the cell’s surface. As their name implies, glucose transporter proteins act as vehicles to ferry glucose inside the cell.

Detailed explanation-4: -Contraction stimulates GLUT4-EGFP translocation to both the sarcolemma and t-tubules. In the basal state, GLUT4-EGFP was found in larger and smaller vesicle structures (Fig.

Detailed explanation-5: -Complete answer: No, GLUT4 may be a passive transporter of glucose down the concentration gradient. It’s a glucose transporter present within the adipose tissues, skeletal and cardiac muscles. It facilitates diffusion of glucose across the cell wall into muscle and fat cells.