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Transport across membranes
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sushma_roberts
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I came across this exam question:
Sodium ions from salt (sodium chloride) are absorbed by cells lining the gut.
Some of these cells have membranes with a carrier protein called NHE3.
NHE3 actively transports one sodium ion into the cell in exchange for one proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how NHE3
does this.
The mark scheme says that it's co-transport and uses ATP, however I thought co-transport doesn't use ATP?
Thanks.
Sodium ions from salt (sodium chloride) are absorbed by cells lining the gut.
Some of these cells have membranes with a carrier protein called NHE3.
NHE3 actively transports one sodium ion into the cell in exchange for one proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how NHE3
does this.
The mark scheme says that it's co-transport and uses ATP, however I thought co-transport doesn't use ATP?
Thanks.
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goldstarfish101
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#2
(Original post by sushma_roberts)
I came across this exam question:
Sodium ions from salt (sodium chloride) are absorbed by cells lining the gut.
Some of these cells have membranes with a carrier protein called NHE3.
NHE3 actively transports one sodium ion into the cell in exchange for one proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how NHE3
does this.
The mark scheme says that it's co-transport and uses ATP, however I thought co-transport doesn't use ATP?
Thanks.
I came across this exam question:
Sodium ions from salt (sodium chloride) are absorbed by cells lining the gut.
Some of these cells have membranes with a carrier protein called NHE3.
NHE3 actively transports one sodium ion into the cell in exchange for one proton
(hydrogen ion) out of the cell.
Use your knowledge of transport across cell membranes to suggest how NHE3
does this.
The mark scheme says that it's co-transport and uses ATP, however I thought co-transport doesn't use ATP?
Thanks.
The carrier protein uses ATP
co transport is just sodium binding to something else and entering via the carrier protein
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S.G.
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tomnelson_
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An example of this occurs in the kidneys in order to maintain reabsorption in the proximal convoluted tubule. Sodium facilitates transport of many molecules back into the bloodstream, however it would be quickly used up and many essential molecules would be left in the tubule to be excreted. In order to maintain enough sodium in the tubule it is continuous returned using a sodium hydrogen exchange.
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