What is the definition of cell membrane?

Question

What is the definition of cell membrane?

Answer 1

It is the part of the cell that holds all the genetic material together.

Answer 2

It's what separates the inside of a cell from the outside; much like a glass holding water.

It is composed of what is called a "phospholipid bilayer".

Let's break the name down and figure out what it really means. "Phospho-lipid" - Just as the name sounds, phospho refers to having a phosphate portion. This is located in the "head" region of the molecule.

"lipid" - lipid is a fat. This is a hydrophobic region of the molecule. It is made up of a long chain of carbons covered with, or saturated, with hydrogen. Because of this, it repels water.

"Bi-layer" - Just as the name sounds this is 2 layers.

Putting this all together: The phosphate heads are arranged so they are in contact with the outside and inside of the cell respectively. Meanwhile, the hydrophobic tails (fats), are arranged so they are in contact with each other, in the middle of the bi-layer.

Still find this confusing? check out this picture:

http://www.fz-juelich.de/inb/inb-1/datap...

Hope this helps!

Answer 3

A cell membrane controls the moving in an out of materials in a cell.