Biology test part 2

Fluid-Mosaic model of the cell membrane

The cell membrane is flexible and has proteins scattered throughout it like a mosaic.

Active transport

Movement of molecules from low to high concentration using energy (ATP).

Passive transport

Movement of molecules from high to low concentration without using energy.

Concentration gradient 

A difference in the amount of a substance between two areas.

Diffusion

Molecules spreading from high concentration to low concentration.

Facilitated diffusion

Diffusion that uses protein channels to move molecules across the membrane without energy.

Endocytosis

The cell taking in large materials by forming a vesicle from its membrane.

Exocytosis

The cell releasing materials by fusing a vesicle with the cell membrane.

Osmosis 

The diffusion of water across a membrane from high water concentration to low water concentration.

Hypertonic

A solution with more solutes than the cell; water leaves the cell and the cell shrinks.

Hypotonic

A solution with fewer solutes than the cell; water enters the cell and the cell swells.

Isotonic

A solution with equal solutes to the cell; water moves equally in both directions and the cell stays the same size.

Aquaporins

Protein channels in the membrane that allow water to pass through quickly.