Question

Which of the following is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal?

A) The sodium ions are moving down their electrochemical gradient while glucose is moving up.
B) Glucose entering the cell along its concentration gradient provides energy for uptake of sodium ions against the electrochemical gradient.
C) Sodium ions can move down their electrochemical gradient through the cotransporter whether or not glucose is present outside the cell.
D) The cotransporter can also transport potassium ions.
E) A substance that blocks sodium ions from binding to the cotransport protein will also block the transport of glucose

Answer 1

The most likely true statement is that the sodium ions move down their electrochemical gradient while glucose moves up against its gradient, facilitated by a symporter in a process of secondary active transport.

Step-by-step explanation:

The correct answer to the question of what is most likely true of a protein that cotransports glucose and sodium ions into the intestinal cells of an animal is: A) The sodium ions are moving down their electrochemical gradient while glucose is moving up. This process is a type of secondary active transport known as a symport system, where sodium ions enter the cell down their electrochemical gradient, and this exergonic process powers the uphill movement of glucose into the cell.

The energy for this process is provided by the sodium-potassium pump, which maintains a high concentration of sodium ions outside the cell by pumping sodium out and potassium in using ATP, thereby establishing the electrochemical gradient needed for cotransport.