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Flashcards in Ch 4 Enzymes and Energy Deck (11):

Enzymes as catalysts

make reactions faster
subclass of proteins
biological catalysts that increase the rate of chemical reactions. Most enzymes are proteins, and their catalytic action results from their complex structure.



is a chemical that:
1. increase the rate of reactin
2. is not itself changed at the end of the reaction
3. does not change the nature of the reaction or its final result



have to break bonds to make new bonds


2 mechanisms of enzyme activity

1. lock and key- substrates fit into active site like a key into a lock and bring substrates together to react
2.Induced fit- like lock and key, but whne substrate lands in active site the make the enzyme shift into a new shape. When the enzyme shifts it forces old bonds to break and new ones to form


Law of Mass Action

the consentration of reactants and products will dicatet which way a reversible reaction will go
carbonic anhydrase: H2CO3-> H2O + CO2


Effects of temp and pH on enzymes

when the rate of an enzymatic reaction is measured at different pH values each enzyme characteristacally exibits peak activity in a very narrow pH range which is the pH optimum
cold molecules move slower therefore the reverse is true


cofactors and coenzymes

ions and smaller organic molecules needed for the activity of specific enzymes
some enzymes with a cofactor requirement do not have a properly shaped active site in the absence of the cofactor
cofactor changes the conformation of the active site, allowing for a better fit between enzyme and its subtrates
cofactors are minerals (Mg, Zn, Cu) join the enzyme to make the active site more attractive to substrate (like iron in catalyse enzyme)
coenzymes are some vitamins that help ozidation reduction reactions (vit B3)


Metabolic pathways

a sequence of enzymatic reactions that begins with an initial substrate, progresses though a number of intermediates, and ends with a final product known as a metabolic pathway
most of the big reactions like breaking down sugar need several steps. Each step catalyzed by a different enzyme and along the way there may be _______ points


End-Product inhibition

(when to store)
when a final product shuts down an enzyme in its own pathway
final product blocks that active site for the time being


How does ATP drive reactions? ATP coupled reactions

ATP is a nucleotide P-P-P-S-B
going to use the energy that bonds the #2 P to the #3P to push a negative #3P onto a substrate or enzyme
ADP- + P- ->ATP


what relation is there betwn the rusty nail and catalase

both have iron, nail does not have catalyst. Liver has catalyst and right active site to align substrates perfectly everytime provides optimal pH of enzymatic activity has evolved to body temp to carry out reactions effectively