Biological Membranes Flashcards
(16 cards)
Function of bilayer in membranes?
Acts as a barrier for most water soluble substances.
Prevents leaking of water soluble molecules.
What are the tails joined by?
Van de vaals forces
What are the heads of the membrane structure joined to?
Water molecules in solution.
By hydrogen bonds.
What are the two different types of membrane proteins?
Intrinsic and Extrinsic
What is the intrinsic Protein in membranes?
Transmembrane embedded in BOTH layers of the membrane.
Examples: channel proteins
Carrier proteins
Glycoproteins
What are extrinsic proteins in membranes?
Found on the surface/ present on ONE side of the bilayer.
Examples: function as enzymes and catalyse chemical reactions - hormones
What are phospholipids?
They are in fluid, free to move within.
Provides membrane flexibility
Describe the proteins in membranes.
Variable in size and shape and scattered around the membrane.
What do channel proteins provide?
A hydrophilic channel.
Function of channel proteins?
Allows small polar molecules and ions to pass passively through the membrane.
Down a concentration gradient.
Function of carrier proteins?
Can change their shape in order to transport molecules across the membrane.
In both passive and active transport.
What are glycoproteins?
They are intrinsic proteins with carbohydrates chains attached.
Function of glycoproteins?
Play a role in cell adhesion in certain tissues.
Important for communication: acts as receptors for chemical signals - process called cell signaling.
Function of Cholesterol in membranes?
Regulates the fluidity of the membrane and adds stability.
What are glycolipids?
They are lipids with attached carbohydrate chain.
What are the function of glycolipids in membranes?
Act as cell markers or antigens for cell-cell recognition.
Recognised by the immune system.
