Membrane transport 1
Subject and importance of the membrane transport. Types of transport (classification). Free diffusion of non-charged particles - first and second Fick’s laws. The Stokes-Einstein equation.
Definition and functions of the membrane transport:
- Transport: Processes of passing through membrane of small molecules and ions. Usually it’s a highly selectable process.
Functions:
- Regulation of the cells volume
- Imports substances necessary for energy & growth in cell
- Maintains the ion gradients & transforms energy
Importance:
- Faults in transport are cause for many diseases.
- Some kind of drugs can restore the normal cells function, changing due to membrane transport.
Types of cellular transport:
PASSIVE TRANSPORT:
- Cell does not use energy
- Molecules move randomly
- Molecules spread out from an area of high concentration to an area of low concentration
There are 3 types of passive transport:
- 1. Diffusion
- 2. Facilitated diffusion - diffusion with help of transport proteins
- 3. Osmosis - diffusion of water
ACTIVE TRANSPORT:
- Cell does use energy
- Actively moves molecules to where they are needed
- Movement from area of low concentration to area with high concentration
There are 3 types of active transport.
- 1. Protein pumps
- 2. Endocytosis
- 3. Exocytosis
Fick’s 2nd law states that the change in concentration with time in a particular region is proportional to the change in the concentration gradient at that point in the system.