When we're thinking of cells, both plant and animal cells have cell membranes. The cell membrane allows different substances and super-tiny particles to move in and out of the cell. The ability to allow different substances and super-tiny particles to pass through it is known as semi-permeability. The key word to remember here is permeability.
What are some things in our everyday lives that have permeability?
AIR FILTERS (this HEPA filter pulls in air and allergens like dust and moves out fresh air for us to breathe)
Our SKIN (which also has pores that allow us to move sweat out of our bodies)
AIR FILTERS (this HEPA filter pulls in air and allergens like dust and moves out fresh air for us to breathe)
Our SKIN (which also has pores that allow us to move sweat out of our bodies)
This is what the inside of our skin looks like.....
And this is what the inside of a cell membrane looks like....
What are the differences?
- the cell membrane has structures going from one side to the other.
- the skin has a greater variety of structures than the cell membrane.
What are the similarities?
- they both have channels through which different things can pass
- they both have an inner layer and an outer layer
CELL MEMBRANE STRUCTURE
Cell membranes have an inner layer of phospholipids and an outer layer of phospholipids. Having this two layers is called having a lipid bilayer ("bi" = "two").
CELL MEMBRANE FUNCTION
Like an air filter which filters allergens or the human skin which secretes sweat to cool down the body, a cell membrane functions to allow different things in and out of the cell!
