Membranes, energy, enzymes Flashcards
What do competitive inhibitors do
bind to active site of enzyme, blocking substrate
What do non competitive inhibitors do
Bind to another site of the enzyme altering its physical conformation, stopping substrate from entering
What do allosteric activators do
Bind to regulatory site on enzyme, locking it from oscillating state into active state
What do allosteric inhibitors do
Binds to enzyme in another site stabilising it in an inactive form so active site is non functional
What does cooperativity mean in terms of enzymes
A substrate is used as an allosteric activator to allow other substates to bind to the active sites
What can diffuse across phospholipid bilayer
small, polar, hydrophobic molecules
What cannot diffuse across phospholipid bilayer and therefore needs transport proteins
large, hydrophilic ions
Types of transport proteins that move with concentration gradient (passive transport)
- channel proteins
- hydrophilic pore, quick
- carrier proteins
- conformational change, slower
How does Na+ / K+ pump work
- Na+ binds
- high energy phosphate linkage triggers conformational change
- Na+ ejected
- K+ binds
- dephosphorylated (phosphate removed)
- back to original configuration
- K+ ejected
Types of transport proteins that move ions against concentration gradient
- ATP driven
- Na+ / K+ pump - Coupled transporters
- electrochemical gradient created to then transport protons + sucrose back in
What are other ways of transport that does not involve proteins
- phago cytosis - food vacuole
- pino cytosis - fluid vacuole
- receptor mediated endo cytosis - for specific molecules in short supply
Describe feedback inhibition
When enough of the product has been formed for use, the product itself can bind to a non competitive site on the enzyme to prevent any more being made
