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Cell Biology > Cell Membranes > Problem
Set
Cell Membranes
Problem Set
Problem
8: Cotransport
Cotransport systems of the intestinal epithelial cells include the_________
in the intestine facing membrane, the energy requiring _____________
facing the blood, and the ______________allowing facilitated diffusion
of glucose out of the cell.
A. |
permease, cotransporters, Na+K+ ATPase |
B. |
cotransporters, CFTR, permeases |
C. |
Na+K+ ATPase, cotransporters, permeases |
D. |
cotransporters, Na+K+ ATPase, permeases
The Na+K+ ATPase moves Na+ out of the
epithelial cells lining the intestine and into the blood.
The reduced concentration of Na+ inside the cell coupled with
high Na+ inside the lumen of the intestine provides a driving
force for the movement of Na+ into the cell.
The co-transporters in the membrane
of the epithelial cell facing the intestine allow Na+ to enter
only when accompanied by either glucose or one of the amino
acids (each have their own set of co-transporters). Glucose
then moves into the blood through a permease in the membrane
between the cell and the blood. Thus, ATP is used as an energy
source to drive Na+ out of the cell resulting in glucose transport
from the intestine to our blood.
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