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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Biology => Topic started by: run-bandit on February 27, 2010, 09:39:24 am

Title: If water is polar then how does it get into the cell?
Post by: run-bandit on February 27, 2010, 09:39:24 am

If water is polar then how does it get into the cell?

Title: Re: If water is polar then how does it get into the cell?
Post by: qshyrn on February 27, 2010, 10:17:48 am

protein channels embedded in the membrane with a hydrophilic lining

Title: Re: If water is polar then how does it get into the cell?
Post by: lexitu on February 27, 2010, 11:10:05 am

Also, water molecules are small enough to fit in between the gaps of the membrane.

Title: Re: If water is polar then how does it get into the cell?
Post by: stonecold on February 27, 2010, 11:26:31 am

yeah, small uncharged molecules like water and urea, diffuse through the gaps between the membrane.  remember that for water it is called osmosis though.

water also moves in and out of the cell through specialised channel proteins called aquaporins.  i.e. facilitated diffusion.

Title: Re: If water is polar then how does it get into the cell?
Post by: run-bandit on February 27, 2010, 12:11:03 pm

but water is polar (slightly charged) won't it be repelled by trying to get through small gaps.

Isn't only this answer right:

Quote from: qshyrn on February 27, 2010, 10:17:48 am

protein channels embedded in the membrane with a hydrophilic lining

Title: Re: If water is polar then how does it get into the cell?
Post by: hasho on February 27, 2010, 12:23:20 pm

aquaporins

Title: Re: If water is polar then how does it get into the cell?
Post by: stonecold on February 27, 2010, 12:26:00 pm

nah, water has a partial positive charge and a partial negative charge, but overall, it is still uncharged.
small uncharged polar molecules can diffuse between the gaps in the cell membrane.