Protein movment in cell membrane?

Debate and discussion of any biological questions not pertaining to a particular topic.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
aic92
Garter
Garter
Posts: 3
Joined: Tue Dec 13, 2011 4:34 pm

Protein movment in cell membrane?

Post by aic92 » Tue Dec 13, 2011 4:42 pm

I was reading about the phospholipid bilayer/membranes and how it's fluid like in nature which is the reason why molecules such as proteins are able to move across it laterally. What I don't understand is which kind of proteins are able to move around the membrane; my book says there's two major types of membrane proteins including integral proteins which are firmly bound to the membrane and peripheral proteins which are not even embedded in the lipid bilayer. If integral proteins are firmly bound and peripheral proteins are not even embedded in the first place, then which proteins exactly are able to move around the lipid bilayer?

User avatar
jonmoulton
Viper
Viper
Posts: 442
Joined: Fri Feb 15, 2008 5:38 pm
Location: Philomath, Oregon, USA

Post by jonmoulton » Tue Dec 13, 2011 5:06 pm

Integral proteins cannot move out of the bilayer, but they can diffuse to any side. Peripheral proteins are associated with one surface, but can scoot around on that surface. If you think of the cell membrane as the surface of a planet then these proteins can move north, south, east, and west, but they generally cannot burrow toward the planet's core or fly off into space.

aic92
Garter
Garter
Posts: 3
Joined: Tue Dec 13, 2011 4:34 pm

Post by aic92 » Tue Dec 13, 2011 5:07 pm

Oh okay. Thanks for the help! :D

aic92
Garter
Garter
Posts: 3
Joined: Tue Dec 13, 2011 4:34 pm

Post by aic92 » Tue Dec 13, 2011 5:45 pm

Actually I just have one last question: Why are cell membranes permeable to non-polar molecules and relatively impermeable to polar molecules?

User avatar
JackBean
Inland Taipan
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm

Post by JackBean » Thu Dec 15, 2011 3:36 pm

do you know, what is the membrane composed of? What properties does it have?
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests