What is required for glucose to exit a cell?

• A. Phosphorylation
• B. Dephosphorylation
• C. Diffusion
• D. Active transport

Answer: (B)

For glucose to exit a cell, it primarily involves facilitated diffusion rather than simple diffusion, phosphorylation, or dephosphorylation. Normally, glucose enters cells via glucose transporters, such as GLUT proteins, which allow it to pass through the membrane down its concentration gradient. When glucose enters the cell, it is often phosphorylated to glucose-6-phosphate, which helps to maintain a concentration gradient favorable for more glucose to enter.

To exit the cell, glucose typically does not require any additional phosphorylation or dephosphorylation steps but follows the gradient based on concentration. Thus, the direct requirement for glucose to exit the cell does not hinge on these processes. Therefore, while dephosphorylation is a broader cellular process, it is not specifically necessary for glucose to exit from the cell membrane when facilitated transport mechanisms are in play.

In summary, the correct understanding centers around glucose transport mechanisms and the role of concentration gradients rather than on the phosphorylation states.