passive transport Flashcards
what are the functions of the membranes
To control the exchange of gases, nutrients and waste between the cell and its surroundings.
what is diffusion
The net movement of particles from a region of high concentration to a region of low concentration
what does it mean when particles reach an equilibrium
When particles have distributed themselves evenly in the system. At equilibrium, the molecules are still moving but are effectively cancelling each other out.
how can diffusion be sped up or slowed down
- concentration
- temperature
what is a simple diffusion
the process of diffusion through the plasma membrane. Simple diffusion only occurs with small and unchanged molecules.
what is facilitated diffusion
Relies on membrane transport proteins to assist particles entering the cell.
what two proteins are involved in facilitated diffusion
- carrier proteins
- channel proteins
what are channel proteins
They have narrow passageways through the membrane, allowing small particles to pass through. Channel proteins rely on the concentration gradients
what are carrier proteins
Will bind to specific molecules on one side of the membrane and change shape to release the molecules on the other side.
