Question

this question has 3 parts.
when the hormone insulin is present, some human cells will move glucose from outside the cell (in the blood) to inside the cell. one way insulin does this is by activating a transmembrane protein called glut4. glucose moves from high concentrations outside the cell to lower concentrations inside the cell through glut4.
what type of membrane transport occurs as glucose moves through the glut4 transmembrane protein?
○ active transport, because glucose is moving down its concentration gradient.
○ passive transport, because glucose is moving against its concentration gradient.
○ passive transport, because glucose is moving down its concentration gradient.
○ active transport, because glucose is moving against its concentration gradient.
does glucose movement through the glut4 transmembrane protein likely need additional energy input? explain why or why not.
b i u t t, i, : : : :
0 / 10000 word limit

Explanation:

• For the multiple - choice part:
• Active transport requires energy (usually ATP) to move substances against their concentration gradient. Passive transport (including facilitated diffusion) does not require additional energy input as substances move down their concentration gradient. Since glucose is moving from high concentration (outside the cell) to low concentration (inside the cell) through a protein (GLUT4, which is a facilitative transporter), this is a form of passive transport (facilitated diffusion).
• For the second part:
• In passive transport (such as facilitated diffusion which is what occurs with GLUT4 and glucose here), substances move down their concentration gradient. The concentration gradient itself provides the "driving force" for the movement, and no additional energy (like ATP) is needed.

Answer:

• Multiple - choice: C. Passive transport, because glucose is moving down its concentration gradient.
• Second part: No, glucose movement through the GLUT4 transmembrane protein does not likely need additional energy input. This is because it is a form of passive transport (facilitated diffusion), and in passive transport, substances move down their concentration gradient. The concentration gradient provides the energy for the movement, so no extra energy (such as ATP) is required.