Cell Membrane Structure

Fluid Mosaic The cell membrane is often referred to as a ‘Fluid Mosaic” Fluid, because the membrane is not static. It is constantly moving and rearranging itself. Mosaic, because it is made up of a variety of different components that are specifically arranged. Video: The inner life of the cell @ 0:22

Phospholipids The cell membrane is primarily made up of phospholipids Explain hydrophobic and hydrophilic

Arrangement of phospholipids

Cell membranes are phospholipid bilayers

Saturated and unsaturated fats No double bonds Cis double bonds/trans fats

Trans fats in the news FDA to ban trans fats

Cholesterol

Unsaturated fats and cholesterol Bend fatty acid tails and membrane embedded cholesterol both lead to membrane fluidity. For animals that live in colder climates, unsaturated fats and cholesterol are beneficial and even necessary for proper membrane function.

Summary Questions Cell membranes are sometimes referred to as a ______________. This is because they are dynamic arrangements of different elements. Cell membranes are made up of a special lipid known as a ___________. Phospholipids have _________ heads and __________ tails. These hydrophilic/phobic interactions create a double layer of phospholipids, also known as a ______ _________. Unsaturated fats (trans and cis double bonds) and cholesterol make membranes more ________.