3.3 to 3.5. Cell Membrane, Diffusion and Osmosis, &Active Transport

Diffusion

The movement of a solute from an area of HIGH concentration to an area of lower concentration.

Osmosis

The movement of WATER across a semi-permeable membrane through diffusion. From HIGH concentration of water to area of LOW concentration of water.

Passive Transport

The movement of materials through a cell membrane without using energy

Selectively Permeable

cell membranes that allows some substances to pass through, while others cannot

Active Transport

The movement of substances AGAINST the concentration gradient. Requires energy (ATP).

Facilitated diffusion

the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins, the channel protein makes it EASIER (facil)

Endocytosis

When the cell membrane folds around large substances so they can ENTER the cell.

Exocytosis

When the cell membrane folds around large substances so they can EXIT the cell.

solute

The substance that is dissolved in a solution

solvent

The substance doing the dissolving

concentration gradient

Difference in concentration of a substance from one place to another.

isotonic

Solution that has an equal concentration of solutes as another solution.

hypertonic

Solution that has a higher concentration of solutes as another solution.

hypotonic

Solution that has a lower concentration of solutes as another solution.

phospholipid structure

2 fatty acids, 1 glycerol, 1 phosphate group

lipid tails

the hydrophobic end of a phospholipid

phosphate head

the hydrophilic end of the phospholipid

Cholesterol

these molecules strengthen a cell membrane

protein channel

a protein that allows the transport of specific substances across a cell membrane