1
Q
functions of cell membranes
A
- boundary that separates living cells from non-living surroundings
- controls which substances pass in and out of cells
- controls uptake of nutrients
- allows waste products to pass out of cell
- cell recognition
2
Q
structure of cell membrane
A
made up of phospholipids and protein
3
Q
structure of a cell membrane - phospholipids
A
- can form bilayers
- phosphate head is a polar molecule - hydrophilic
- 2 fatty acid tails are non-polar - hydrophobic
- the phospholipid allows lipid-soluble (non-polar) molecules to enter and leave
- phospholipid prevent water soluble (polar) molecules from leaving
4
Q
structure of a cell membrane - extrinsic proteins
A
- on the surface of a bilayer or partially embedded in it
- provide structural support
5
Q
structure of a cell membrane - intrinsic proteins
A
- extend over both phospholipids bilayers
- transport protein moves molecules through active transport
- carrier protein moves polar molecules through diffusion
