Structure and function of membranes 2.1.5 (a.b) Flashcards
role of membranes
compartmentalisation
site of chemical reactions
controls what enters and leaves
maintaining chemical gradients
cell signalling
what is compartmentalisation?
the formation of separate membrane-bound areas in a cell
what makes up the plasma membrane?
the phospholipid bilayer
what is the phospholipid bilayer made up of?
hydrophilic phosphate heads pointing outwards
hydrophobic fatty acid tails pointing inwards
creates a hydrophobic core
what is the fluid-mosaic model?
phospholipids are free to move around and proteins are randomly embedded in the bilayer
what are the two types of membrane proteins?
intrinsic
extrinsic
what are intrinsic proteins?
proteins which are embedded through both layers of a membrane
what is a channel protein?
a hydrophilic channel which allows for the passive movement of polar molecules down a concentration gradient
what is a carrier protein?
allow for passive transport down the concentration gradient
AND
for active transport against the concentration gradient
what are glycoproteins?
intrinsic proteins with an attached carbohydrate chain of varying length
role of glycoproteins
- cell adhesion
- receptors for signalling and hormones
- antigens for self recognition
what are glycolipids?
lipids which have a carbohydrate chain attached
role of glycolipids
are antigens
properties of intrinsic proteins
they have hydrophobic R-groups which interact with the hydrophobic core of the bilayer
properties of extrinsic proteins
they have hydrophillic R-groups which interact with the polar phosphate heads
