Plasma Membrane - so that the polar heads are oriented...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Plasma Membrane The plasma membrane surrounds the cell and functions as an interface between the living interior of the cell and the nonliving exterior. All cells have one. It regulates the movement of molecules into and out of the cell. Membrane Structure The fluid-mosaic model states that membranes are phospholipid bilayers with protein molecules embedded in the bilayer. Phospholipids Most of the lipids in a membrane are phospholipids . Phospholipids contain glycerol, two fatty acids, and a phosphate group. The phosphate group is polar ( hydrophilic ), enabling it to interact with water. The fatty acid tails are nonpolar ( hydrophobic ) and do not interact with water. Phospholipid Bilayers Phospholipids spontaneously form a bilayer in a watery environment. They arrange themselves
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: so that the polar heads are oriented toward the water and the fatty acid tails are oriented toward the inside of the bilayer (see the diagram below). In general, nonpolar molecules do not interact with polar molecules. This can be seen when oil (nonpolar) is mixed with water (polar). Polar molecules interact with other polar molecules and ions. For example table salt (ionic) dissolves in water (polar). The bilayer arrangement shown below enables the nonpolar fatty acid tails to remain together, avoiding the water. The polar phosphate groups are oriented toward the water....
View Full Document

This note was uploaded on 12/15/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

Ask a homework question - tutors are online