using the example of the Na+ symporter, is what how i'm going about explaining it correct? thanks in advance.
energy from ATP causes Na+ to be pushed out of the cell. Now that there's a higher concentration of Na+ outside the cell, Na+ will want to move back into the cell but it can't because the hydrophobic core is impermeable to ions. When glucose is present, Na+ can transport glucose into the cell against it's concentration gradient, using the energy stored in it's gradient (Na+ gradient), and so they both move into the cell together.
i'm a little confused, i don't think what i'm thinking is correct because if Na+ can't move across the hydrophobic core, why can it when glucose is there? I know Na+ can move across the hydrophobic core by carrier or channel mediated transport so is one of those used for contransporting?
energy from ATP causes Na+ to be pushed out of the cell. Now that there's a higher concentration of Na+ outside the cell, Na+ will want to move back into the cell but it can't because the hydrophobic core is impermeable to ions. When glucose is present, Na+ can transport glucose into the cell against it's concentration gradient, using the energy stored in it's gradient (Na+ gradient), and so they both move into the cell together.
i'm a little confused, i don't think what i'm thinking is correct because if Na+ can't move across the hydrophobic core, why can it when glucose is there? I know Na+ can move across the hydrophobic core by carrier or channel mediated transport so is one of those used for contransporting?
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You have the right information, but you are missing a few things that are making it confusing, both to you and the teacher.
It's important to say that the Na+ can't diffuse across the cell membrane because the lipid bi-layer has an ion impermeable hydrophobic core.
The reason Na+ can cross back in to the cell with glucose is because of the Symporter.
The cell membrane is like a wall around a city: You can't go through a wall, you have to use a door. The SymPorter/CoTransporter is one of many special doors, called "channels" which, most of which are made up of trans-membrane proteins. There are hundreds of different channels, some are very specific while others are very permeable, but each has a specific and exact function.
The channel you are talking only allows gluten in when there is Na+ with it. That's where it gets its name. The prefixes "co" and "sym" mean "with" or "together. You see these in words like "CoWorker" and "SymBiotic".
This name differentiates it from other transporters, such as ConTransporters, which allow one thing in only when it lets a different thing out ( like a revolving door, if you've ever used one).
I hope this helps. Let me know if it's still unclear.
It's important to say that the Na+ can't diffuse across the cell membrane because the lipid bi-layer has an ion impermeable hydrophobic core.
The reason Na+ can cross back in to the cell with glucose is because of the Symporter.
The cell membrane is like a wall around a city: You can't go through a wall, you have to use a door. The SymPorter/CoTransporter is one of many special doors, called "channels" which, most of which are made up of trans-membrane proteins. There are hundreds of different channels, some are very specific while others are very permeable, but each has a specific and exact function.
The channel you are talking only allows gluten in when there is Na+ with it. That's where it gets its name. The prefixes "co" and "sym" mean "with" or "together. You see these in words like "CoWorker" and "SymBiotic".
This name differentiates it from other transporters, such as ConTransporters, which allow one thing in only when it lets a different thing out ( like a revolving door, if you've ever used one).
I hope this helps. Let me know if it's still unclear.