Plasma Membrane Flashcards
Properties of the plasma membrane
Flexible, able to fuse and break easily
Allow cellular compartments to have different compartments eg PH
Made of phospholipids in a bilayer
Polar water soluble hydrophilic heads and non polar lipid soluble hydrophobic tails
Explain why phospholipids form a bilayer in plasma membranes
- phospholipid have a polar water soluble phosphate group which is hydrophilic so will face the aqueous solution
- fatty acid tails are non polar lipid soluble and hydrophobic so will move away from aqueous environments
- as both tissue fluid and cytoplasm is aqueous phospholipid form 2 layers with the tails facing in and the heads facing out
How does the fluid mosaic model describe the structure of the plasma membrane
- Shows proteins are distributed throughout the bilayer in a mosaic pattern
- shows membrane is fluid and has considerable side ways movement of molecules within it- protein can move freely
- the ease in which protein moves is dependant on the number of phospholipids with unsaturated fatty acid chains in the bilayer
- unsaturated fatty acids allow fluidity as the kinks in the chain allow space between the phospholipids
Function of hydrophilic phosphate head
Attracts water and polar solutes
Function of hydrophobic fatty acid tail
Attracts lipid soluble non polar molecules OR barrier to polar molecules
Function of glycolipid, glycoprotein and carbohydrate
Receptor
Function of cholesterol
Regulates membrane fluidity. High cholesterol = high fluidity
Assists impermeability
Function of peripheral protein
Bind to carbohydrates OR acts as a receptor
Function of channel protein
Osmosis/ active transport/ diffusion
What type of molecule can and cannot diffuse through the bilayer
Can: lipid soluble, non polar, uncharged
Cannot: water soluble, polar, charged
