Here's a breakdown:
* Passive transport: Movement of substances across a cell membrane without the use of cellular energy (ATP). It relies on the second law of thermodynamics, moving from an area of high concentration to low concentration.
There are several types of passive transport:
* Simple diffusion: Movement of a substance across a membrane from an area of high concentration to an area of low concentration. This doesn't require any membrane proteins.
* Facilitated diffusion: Movement of a substance across a membrane with the help of a membrane protein. This protein acts as a channel or carrier for the substance.
* Osmosis: Movement of water across a semipermeable membrane from an area of high water concentration to an area of low water concentration.
Active transport, on the other hand, requires cellular energy (ATP) to move substances against their concentration gradient, from an area of low concentration to an area of high concentration.
