Question

There are two glucose transporters, GLUT1 and GLUT4. For GLUT1, the Km for glucose is about 1.5 mM. For GLUT4, it is 20 mM. If the extracellular glucose concentration is now 10 mM, which one will transport glucose into cells more efficiently?

A. GLUT1
B. GLUT4

Answer 1

GLUT1 will transport glucose into cells more efficiently than GLUT4 when the extracellular glucose concentration is 10 mM due to its lower Km value, indicating a higher affinity for glucose.

Step-by-step explanation:

The difference in Km values for GLUT1 and GLUT4 indicates their affinity for glucose at a given concentration. A lower Km value signifies a higher affinity for glucose at low concentrations.

When the extracellular glucose concentration is 10 mM, GLUT1, with a Km of 1.5 mM, will transport glucose more efficiently into cells compared to GLUT4, which has a Km of 20 mM. GLUT1 is already near its optimal functioning concentration at 10 mM, whereas GLUT4 is far from its optimal concentration and will not function as efficiently.