Active and Passive Transport

Active transport is the movement of molecules across a cell membrane from a region of lower concentration to a region of higher concentration, using energy in the form of ATP.

Passive transport is the movement of molecules across a cell membrane without the use of energy, moving from an area of higher concentration to an area of lower concentration.

In a hypotonic solution, water moves into the cell, causing it to swell and potentially burst.

In a hypertonic solution, water moves out of the cell, causing it to shrink.

An isotonic solution has the same concentration of solute particles as the cell, resulting in no net movement of water.

Osmosis is the diffusion of water molecules across a selectively permeable membrane from an area of lower solute concentration to an area of higher solute concentration.

Facilitated diffusion is a type of passive transport that uses protein channels to help move particles across the cell membrane.

Endocytosis is the process by which a cell engulfs material from the outside environment, bringing it into the cell.

Exocytosis is the process by which a cell expels materials to the outside environment, often using vesicles.

The sodium-potassium pump is an active transport mechanism that moves sodium ions out of the cell and potassium ions into the cell against their concentration gradients.