Movement across membranes

[Yacoubb]

Aquaporins form pores in the membrane of a cell and mainly allows for the movement of water molecules across the cell membrane. Water can also travel directly through the cell membrane and be active transported out of the cell. Is there a specific moment in time were the aquaporins are used?

Good point because aquaporins enable the facilitated diffusion of water molecules.. I've just never happened to know when lol!

[thushan]

Aquaporins form pores in the membrane of a cell and mainly allows for the movement of water molecules across the cell membrane. Water can also travel directly through the cell membrane and be active transported out of the cell. Is there a specific moment in time were the aquaporins are used?

Aquaporins are only found in some cells, from memory tubule cells in the kidney if I am not mistaken.

[golden]

Aquaporins are only found in some cells, from memory tubule cells in the kidney if I am not mistaken.

Yeah that sounds right from what I recall.

[peterpan101]

why does glucose pass through dialysis but not a cell membrane ?

[paulsterio]

why does glucose pass through dialysis but not a cell membrane ?

It does pass through a cell membrane.

P.S. It passes through kidney cells better due to aquaporins.

[peterpan101]

It does pass through a cell membrane.

P.S. It passes through kidney cells better due to aquaporins.

sorry another question does salt ? because its polar?

[Yacoubb]

sorry another question does salt ? because its polar?

Not 100% on this, and please correct me if I'm wrong, but I think that salt in the form of a hypertonic solution can induce the osmotic exit of water molecules from the cell (an area of low solute concentration when placed in a hypertonic solution) to the extracellular matrix (an area of high solute concentration). But when you say NaCl, I think that it wouldn't readily diffuse across and would probably do so by active transport via the protein channel.

[pi]

Salt (NaCl) is not polar.

[Smiley_]

Salt (NaCl) is not polar.

so it can travel through a membrane ?


will it travel thorough dialysis?

[pi]

NaCl isn't found as NaCl, but rather the ions Na+ and Cl-. NaCl is an ionic compound. Ions can not freely travel through the cell membrane.

[Smiley_]

NaCl isn't found as NaCl, but rather the ions Na+ and Cl-. NaCl is an ionic compound. Ions can not freely travel through the cell membrane.

would it travel through dialysis

[Bad Student]

would it travel through dialysis

Since the membrane of a dialysis is made of cellulose and not phospholipids, then it should be possible for salt to pass through as long as the pores are big enough.