photosynthesis Questions with Complete
Solutions
Energy coupling Use of an exergonic process to drive an endergonic process (ATP helps
mediate such)
ATP Broken down to ADP + phosphate by hydrolysis (the addition of water)
Phosphorylation Using specific enzymes a cell couples the energy of ATP hydrolysis with
endergonic processes (done by transferring a phosphate group to another molecule which in turn
becomes phosphorylated)
ATP interaction Catabolism drives ATP while the breakdown of ATP drives Anabolic
reactions
Enzymes Protein catalysts that increase the rate of reactions without being consumed
,Activation energy Initial investment of energy for starting a reaction (energy required to
contort the reactant molecules so bonds can break)
Amount of energy needed to push the reactants to the top of an energy barrier or uphill so that
the downhill part of the reaction can begin
Often in the form of heat
Enzymes lower activation energy
Active site Region of the enzyme that binds to the substrate in a lock and key fashion
(may undergo an induced fit)
Manner in which enzymes speed up reactions: Properly orienting reactants to favor
reaction
Stress or bending substrate to favor a reaction
Provide local conditions that favor a reaction
Rate of reaction Dependent on concentration of substrate and amount enzyme
Factors that affect enzyme activity pH, temperature, solute concentrations, etc
(37 degrees C is optimal human enzyme temp while pH of 2 is optimal for stomach enzymes)
, Cofactors Nonprotein helpers for catalytic activity
If it is organic called a coenzyme
Enzyme inhibitors Enzyme activity regulated when it is not needed
Many antibiotics inhibit bacterial enzymes and not our own
Reversible (does not permanently damage enzymes)
vs
Irreversible (permanently alters enzymes)
vs.
Competitive- competes with substrate for active site
vs.
Noncompetitive- binds elsewhere causing a shape change in the active site
Allosteric site In noncompetitive inhibition can bind here
Can also stimulate enzyme's activity
Binding of activator vs. inhibitor