Cell Membrane Structure and Function

Flashcards on cell membrane structure and function.

Fluid Mosaic Model

Describes membrane structure as a 'sea of lipids in which proteins float like icebergs'; membrane is 50% lipid & 50% protein, held together by hydrogen bonds.

Phospholipids

Lipid molecules arranged in two parallel layers, each molecule being amphipathic (polar and nonpolar regions).

Amphipathic

Having both polar (hydrophilic) and nonpolar (hydrophobic) regions.

Integral Proteins

Proteins that extend into or completely across cell membranes (transmembrane protein), possessing both hydrophobic and hydrophilic regions..

Peripheral Proteins

Proteins attached to either the inner or outer surface of cell membranes and are easily removed from it.

Receptor Proteins

Membrane proteins that act as cell signal receptors.

Selective Permeability

The membrane's ability to allow some substances to cross more easily than others, due to its molecular organization.

Diffusion

Movement of particles from an area of high concentration to an area of low concentration.

Electrical Gradient

The influence on ion movement due to membrane potential in addition to the concentration gradient.

Osmosis

The net movement of H2O through a selectively permeable membrane from an area of high water concentration to an area of lower water concentration.

Aquaporins

Water channel proteins that mediate Pf (water movement through water channels).

Osmotic Pressure

The pressure applied to a solution to prevent the inward flow of water across a semi-permeable membrane.