Cell Membrane Structure and Function

Fluid mosaic model
a mixed composition or a mosaic of phospholipids.

Transport proteins
let specific solutes diffuse through a membrane spaning channel.

Receptor proteins
Bind extracellular substances.

Recognition proteins
Indentity tags for each specie.

Adhesion proteins
help cells of the same type to locate each other and remain the proper tissue.

Communication Proteins
form channels that match up across the plasma membranes of two cells.

Concentration gradient
diferrences in number per unit volume of moleculesof a substance between two adjoining regions.

Diffusion
is the name for the net movement of like molecules or ions down concentration gradient.

Electric gradient
is a difference in electric charge between adjoining regions.

Pressure gradient
Difference in pressure exerted per unit volume between two adjoinig regions.

Osmosis

the diffusion of water across a selectively permeable membrane.

Hypotonic solution

the one with fewer solutes.

Hypertonic solution
The one having more solutes.

Isotomic solution
no net osmotic movement.

Hydrostatic pressure
pressure against the wall or membrane that contains it.

Osmotic pressure
one measure of the tendency of water to follow its water concentration gradient.

Endocytosis
a small patch of plasma membrane.

Exocytosis
a vesicle moves to the cell surface and then the protein-studded lipid bilayer of its membrane.

Phagocytosis
is a common endocytic pathway.