chapter 8 pt 1 Flashcards
catabolism
break bonds of large molecules
-release energy
anabolism
forms large macromolecules
-needs energy
what do enzymes do to chemical reaction
increase rate by lowering energy of activation
-not permanetly altering the reaction
-it is a physical site for substrate molecules to bind
simple enzyme
only proteins
conjugated enzymes
holoenzymes
-have protein and non protein molecules
-apoensyme and cofactors (can have one or both)
apoenzyme
part of the conjugate enzyeme that is protein
-secondary (h bond), tertiary (side group) and some quaternary structures
-site for substrate binding (active site) or catalytic site
-when the substrate moves into the active site a temporary enzyme substrate union occurs
cofactors
non protein part of the conjugates enzyme
-can be metallic (iron, copper, magnesium)
-can be coenzymes (an organic molecule like a vitamin)
-heme of hemoglobin
induces fit
the temporary union of the substrate moving into the active site
-this is not the lock and key model
-the key (substrate) never fits the lock right it has to be forced into the apoenzyme
synthesis
condensation reactions
-anabolic reaction that forms covalent bonds
-requires atp and releases one water molecule for each bond formed
hydrolysis reaction
Catabolic reaction
Input water to break bonds
-released energy can be harvested and used elsewhere
enzymes are sensitive to what?
their environment
-temp, ph and osmotic pressure of their organisms habitat
-ex: extremophile pol for pcr
labile
chemically unstable enzymes from changes in organisms habitat
denaturation
weak bonds that maintain the shape of the apoenzyme are broken due to changes in the organisms environment
constitutive enzymes
always present and produced in equal amounts/ rates regardless of the amount of substrate
regulated enzymes
not always present their production has to be turned on / induced and then repressed/ turned off in response to changes in the substrate concentration
how do we control enzyme activity
enzyme represion and enzyme induction
enzyme repression
inhibits at the genetic level by controlling the synthesis of enzymes
enzyme induction
enzymes are only made when suitable substrates are present
direct enzyme control
competitive inhibition and noncompetitive inhibition
competitive inhibition
substances that resemble the normal substrate and compete with the substrate for the active site
noncompetitive inhibition
enzymes are regulated by the binding of molecules other than the substrate away from the active site
-allosteric inhibition
-molecule changes the shape so the original cant bind anymore
steps of metabolic pathways are all….
all catalyzed by a different enzyme
metabolic pathway
sum of the steps from start to finished product
mutlienzyme system shaptes
linear, cyclic, branched (divergent and convergent)
