sushma_roberts
Badges: 8
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 3 years ago
#1
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.
0
reply
goldstarfish101
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 3 years ago
#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.

The carrier protein uses ATP
co transport is just sodium binding to something else and entering via the carrier protein
0
reply
S.G.
Badges: 22
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 3 years ago
#3
Protein used ATP.

Just think low to high = ATP will be used.
0
reply
tomnelson_
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 3 years ago
#4
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.
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

What is your favourite revision method?

Taking notes manually (63)
22.34%
Note taking apps (6)
2.13%
Flashcards (54)
19.15%
Revision guides (16)
5.67%
Past papers (132)
46.81%
Something else (let us know in the thread) (11)
3.9%

Watched Threads

View All
Latest
My Feed