If Na+ levels were depleted in the extracellular fluid, rate of glucose movement would

Question

A.  increase.
B.  decrease.
C.  stay the same.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?

Gather Content
· What do you know about coupled transport of glucose and sodium? What other information is related to the question?

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

B.  decrease.

Clarify Question
· What is the key concept addressed by the question?
        o The question asks about coupled transport of glucose and sodium.
· What type of thinking is required?
        o You are being asked to apply your knowledge about coupled transport of glucose and sodium.

Gather Content
· What do you know about coupled transport of glucose and sodium? What other information is related to the question?
        o The active glucose transporter uses the Na+ gradient produced by the Na+/K+ pump as a source of energy to power the movement of glucose into the cell. In this system, both glucose and Na+ bind to the transport protein, which allows Na+ to pass into the cell down its concentration gradient, capturing the energy and using it to move glucose into the cell through a symporter.

Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o If Na+ levels drop on the outside of a cell, less Na+ is available to move to the inside of the cell, bringing glucose along with it through the symporter. As a result glucose transport will decrease.

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to apply your knowledge about coupled transport of glucose and sodium. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you think that sodium and glucose were transported by an antiporter? Did you think that glucose transport was not linked to Na+ transport?