Focus your attention on step three of the Focus Figure. During this step, the pu
ID: 3521346 • Letter: F
Question
Focus your attention on step three of the Focus Figure. During this step, the pump releases N a + into the extracellular fluid. N a + has now been transported from the cytoplasm to the extracellular fluid. Which of the following best describes why N a + isn’t also transported in the opposite direction—from the extracellular fluid to the cytoplasm? View Available Hint(s) Focus your attention on step three of the Focus Figure. During this step, the pump releases into the extracellular fluid. has now been transported from the cytoplasm to the extracellular fluid. Which of the following best describes why isn’t also transported in the opposite direction—from the extracellular fluid to the cytoplasm? In this pump conformation, N a + can no longer bind. In this pump conformation, K + can now bind. In the extracellular fluid, the concentration of N a + is less than the concentration of K + . The concentration of N a + in the extracellular fluid is less than its concentration in the cytoplasm.
Explanation / Answer
Answer.
In this pump conformation Na+ can no longer bind .
Na+ is not transported in the opposite direction from extracellular fluid to cytoplasm because it does not bind.