energy and enzymes Flashcards
do things tend towards order or disorder?
disorder
what is NAD and what does it turn into?
an enzyme co factor that acts to carry electrons. found in all living cells.
In REDOX rxns, an H+ is transferred to NAD+ forming NADH.
NAD+ + 2e’s and 2H+’s = NADH.
The compound is a dinucleotide, because it consists of two nucleotides joined through their phosphate groups
why is NAD an enzyme ‘co factor’ ?
It’s a co factor because the enzymes needs the NAD+ to do its job; NAD+ and H+ plug into enzyme for reaction to occur
structure NAD+?
It’s a nucleotide (base, sugar , phosphate) + another nucleotide with an unfamiliar base (nicotinamide) which has a + charge
is NADH recycled?
yes. after enzyme releases it, diffuses away and is available to other molecules
endergonic
when delta G is positive- requires energy
exergonic
- Delta G is negative. Favorable/spontaneous
ATP hydrolysis= ___ kcal
-7.3
how does exergonic ATP hydrolysis drive other reactions?
- Can create coupled reactions. Use ATP hydrolysis + to push other unfavorable rxn. Its like how sodium can bring glucose in with it- pair good with bad (aka non spontaneous rxn)
example of a process that is only energetically favorable due to ATP production
glutamine formation.
glutamic acid -> glutamine = G of 3.4.
ATP-> ADP + P = -7.3.
overall G is -3.9 kcal/mol; it goes!
how do enzymes work with energy and rate of rxn? are they used up?
Enzyme lowers activation energy of rxn. Enzymes increase rate of rxn without changing equilibrium. never used up or changed.
what exactly are enzymes?
proteins, with binding sites
what occurs when the substrate goes into the binding site?
enzyme tightens grip around it , called ‘induced fit’ , by using things like H-bonds
describe the process of the enzyme working once substrate is plugged in.
- induced fit
- Destabilizes the bonds as they exist.
- by destabilizing the bonds, allows substrate to overcome the linkage between the components (ex: sucrose monomers), releasing the monomers.
- Once bond has destabilized, sugars easily fall out. Enzyme remains unchanged.
describe an enzyme pathway
product of 1st Enzyme gets taken up by 2nd E, taken up by 3rd etc. each one spits out a new substrate and eventually the last enzyme gives us a useful product.
