Organsisms Exchange Substances With Their Environment Flashcards
Describe molecules that undergo simple diffusion across a membrane.
Small, lipid soluble
Describe the molecules that undergo facilitated diffusion.
Large, water soluble molecules
What do molecules undergoing facilitated diffusion require?
A channel protein
Describe the type of molecule that can move via active transport
Any molecule!
What does a molecule going through active transport require?
A carrier protein
What is co transport?
Molecules travelling across a membrane together
What does co transport require?
A carrier protein
Describe the action of bile salts on lipids.
Bile salts emulsify fats into micelles (tiny droplets)
Describe the action of pancreatic lipases.
They break down triglycerides into a monoglyceride and two fatty acids
What is the role of endopeptidases?
They hydrolyse internal peptide bonds in the middle of proteins.
This forms a shorter polypeptide chain, so there are more ends for proteases to work on
Describe the role of exopeptidases.
They hydrolyse peptide bonds at the end of polypeptide chains to remove terminal amino acids or dipeptides
What is the role of cholesterol in the cell surface membrane
It reduces fluidity of the membrane, therefore stabilising it.
Describe the role of intrinsic proteins in the cell surface membrane (channel and carrier proteins)
They bring large molecules and ions across the membrane
What is the role of glycoproteins and glycolipids?
They are involved in cell signaling, cell adhesion and cell recognition
Describe how cells surface membrane may be adapted for rapid transport of molecules
Increased surface area, more channel and carrier proteins.
