L3 - Plasma Membrane And Organelles Flashcards
Phospholipid bilayer
Made of double layer of phospholipids to create a divide with the hydrophilic head and hydrophobic tail
Saturated tails
Creates viscous membrane due to fully carbon bonded tails
Unsaturated tails
Fluid membrane due to the double or triple bonds in the tail creating kinks
Temperatures effect on membranes
High temps, more fluid, low temps, more solid
Cholesterol effects on membrane
Stabilises membrane fluidity, creating the perfect balance between too thick and too thin
Membrane protein purpose
Signal transduction, cell recognition, intercellular joining, linking cytoskeleton and extra cellular matrix, and membrane transport.
Signal transduction
Relay messages from body into the cell
Cell recognition
A way to recognise other cells, using glycoproteins.
Intercellular joining
Protein to protein bonds that connect cells
Linking cytoskeleton and extra cellular matrix
Allows cells to physically connect with protein structures outside of the cell.
Membrane transport
Small amounts of molecules across membrane
Diffusion
Passive transport, molecules move down the concentration gradient, only for non polar molecules
Facilitated diffusion
Passive transport, movement through channel or carrier proteins, down the concentration gradient, carries undergo a shape change to guide the molecule.
Osmosis
Facilitated diffusion through aquaporins, from high water concentration to low water concentration
Active transport
Proteins requiring energy to push substances against the concentration gradient.
Co-transport
Indirect active transport, using active transport to push something out so it can join to another molecule and passively transport back in.
