EVERYDAY SCIENCE

Detailed explanation-1: -All channel proteins and many carrier proteins allow solutes to cross the membrane only passively (“downhill”), a process called passive transport, or facilitated diffusion.

Detailed explanation-2: -An example of passive transport is diffusion, the movement of molecules from an area of high concentration to an area of low concentration. Carrier proteins and channel proteins are involved in facilitated diffusion.

Detailed explanation-3: -During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.

Detailed explanation-4: -Osmosis is a form of passive transport when water molecules move from low solute concentration(high water concentration) to high solute or low water concentration across a membrane that is not permeable to the solute.

Detailed explanation-5: -In facilitated diffusion, molecules diffuse across the plasma membrane with assistance from membrane proteins, such as channels and carriers. A concentration gradient exists for these molecules, so they have the potential to diffuse into (or out of) the cell by moving down it.