Chapter 8 Section 4+5 Flashcards
Enzyme
macromolecule that acts as a catalyst that speeds up reaction w/out being consumed by the reaction
Activation Energy
the initial amount of energy needed to start a reaction
The Ea creates a ____ that determines what?
barrier, the speed of a reaction
Catalysis
the process where enzymes reduces the Ea barrier in order for reactant molecules to reach a transition state at moderate temps.
Substrate
the reactant an enzyme acts on
Enzyme-Substrate Complex
when enzyme binds w/substrate
Active Site
restricted region the enzyme binds to substrate
Induced Fit
enzyme changes shape slightly to fit in more snuggly w/ substrate to enhance ability to catalyze
Ways an active site can lower Ea and speed up reaction
- acting as a template for substrate orientation
- stressing the substrates & stabilizing the transition state
-providing favorable microenvironment - participating directly in catalytic reaction
synthesis
active site orients substrate in correct position for reaction
synthesis
active site orients substrate in correct position for reaction
digestion
active site binds w/ substrate & puts stress on bonds that must be broken, making it easier to separate molecules
What are responsible for the fit of substrate & active site & enzyme?
H-Bonds
An increase in enzymes means an increase in what?
reaction rate
When does a reaction level off when there is an enzyme concentration?
when substrate is limiting factor & not all enzymes can find substrate
An increase in substrate means an increase in what?
reaction rate
When does a reaction level off when there is an substrate concentration?
when all enzyme have active sites engaged, enzymes are saturated, max. rate of reaction
Optium Temp.
greatest # of molecular collisons, humans 35-40 C
Heat above Optium Temp.
the energy level disrupts bonds in enzymes and b/tw enzyme & substrate
Cold Temp.
molecules move slower, decrease in collision b/tw enzyme & substrate
Changes in pH
disrupts bonds & charged amino acids, disrupts 3D shapes
Optimal pH
6-8
Changes in Salinity
disrupts bonds, 3D shapes & attraction b/tw charged amino acid
What are the types of activators
cofactors & coenzymes
Cofactors
non-protein, small inorganic compounds & ions, bound within enzyme molecule
Coenzymes
non-protein, organic molecules
Compettive Inhibator
mimics substrate competing for active site
How can a Competitive Inhibitor be overcome?
Increasing substrate concentration, so it out competes inhibitor for active site
Inhibitors
molecules that reduce enzyme activity
Non-Competitive Inhibitor
binds to site other than active site
When an allosteric inhibitor binds w/ allosteric site, what happens to the enzyme?
the enzyme changes shape
Conformational change
active site is no longer functional binding site
Irreversible Inhibition
inhibitor permanently binds w/enzyme
-competitive
permanently binds to active site
-allosteric
permanently binds to allosteric site
permanently changes enzyme’s shape
Allosteric Regulation
conformational changes by regulatory molecules
inhibitors
-keeps enzyme in inactive form
Allosteric Regulation
conformational changes by regulatory molecules
inhibitors
-keeps enzyme in inactive form
Metabolic Pathways
Chem reactions of life are organized in pathways, divide chem reactions into many small steps
Feedback Inhibition
Regulation & coordination of production
-product is used by next step in pathway
-final product is inhibitor of earlier step
allosteric inhibitor of earlier enzyme
-no unnecessary accumulation of products
Caspases
enzymes that are activated when a cell has ordered to go through apoptosis
