enzymes Flashcards

1
Q

enzymes are ____ catalysts

A

biological

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2
Q

biological catalysts have milder reactions compared to chemical catalysts and have greation reaction _____ with respect to substrates and products (have capacity for regulation)

A

specificity

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3
Q

why is it important that proteins and enzymes are regulated

A

to stay away from disease state but also to facilitate interactions (can change structure or use cofactors, remove things physically, storage or phosphorylation)

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4
Q

enzymes ____ reaction rates compared to uncatalyzed reactions and chemically catalyzed reactions n

A

increase

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5
Q

enzymes use _____ conditions comared to chemical catalysis

A

milder

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6
Q

nitrogen fixation can be catalyzed by

A
  1. lightning
  2. haber process (150-250 atmospheres)
  3. symbiotic bacteria in root nodules of legumes
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7
Q

enzymes have reaction specificity as well as _____ specificity and ____

A

geometry (of chemical structures) & stereo

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8
Q

the regulation of the activity of an enzyme by binding of an inhibitor or activator at a site on the protein separate from the substrate binding site

A

allostery

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9
Q

regulation: phosphorylation, acetylation, and removal of inhibitory peptides

A

covalent modification

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10
Q

regulation of enzymes: assembly into ____ complexes

A

macromolecule

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11
Q

regulation of metabolic pathway by the inhibition of enzyme that catalyzes a reaction early in the pathway by the product of the pathway

A

feedback inhibition

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12
Q

the ____ is missing a cofactor or co enzyme

A

apoenzyme

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13
Q

when a ____ contains a cofactor or coenzyme and can act on substrate

A

haloenzyme

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14
Q

common names of enzymes end in

A

ase

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14
Q

some enzymes need help to catalyze their reactions so they use a ____

A

cofactor

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14
Q

co factors can be

A

small molecules or metal ions

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15
Q

organic cofactors derived from vitamins, may associate transiently or be tightly linked

16
Q

delta G double dagger is

A

activation energy barrier

16
Q

the standard free energy change from product to substrate is

A

standard free energy change

17
Q

delta G’° is how ___ that the reaction will happen

18
Q

delta G double dagger is how ___the reaction will take place

19
Q

enzymes can only change which delta G

A

delta G double dagger

20
Q

a large delta G double (large activation barrier) dagger means ___ k and ___ reaction

A

small (rate constant) , slow

21
Q

delta G’° < 0 has more ___ than __ at equilibrium (forward rxn is favorable)

22
if delta G double dagger is big enough it will never reach equilibrium no matter how ____ delta G'°
negative
23
enzymes low ___
deltaG double dagger
24
ES and EP can be considered __ ___
reaction intermediates
25
the step with the highest energy barrier is (has smallest k)
rate limiting step
26
enzymes catalyze both forward and ___ reactions
reverse
27
what is a catalyzed reaction step wise
S+E <---> ES <----> EP <---> P + E
28
an enzymes active site should be complimentary to the _____ state to break up products
transition
29
if the enzyme is complimentary to substrate it will stabilize ___ state which increases the delta G double dagger significantly
ES
30
catalytic power of enzymes derived from
1. binding energy 2. binding is optimized to the transition state
31
conversion from two free reactants to one single transition state is entropically _____
unfavorable
32
uncatalyzed unimolecular reactions has a flexible reactant ---> rigid transition state; the conversion is entropically _______
unfavorable
33
enzymes uses the binding energy of substrates to organize reactants to fairly rigid ES complex; when is entropy cost paid
during binding
34
interactions between S and H2O are replaced by S and E; increases reaction rate
desolvation of substrates
35
catalysis involves formation of ____ bonds
covalent
36
specific acid base catalysis means that donation/ abstraction of charge is carried out by _____
water
37
occurs frequently with general acid base catalysis and results in new reaction pathway that are uncatalyzed
covalent catalysis
38
as long as the steps involved in forming and breaking the covalent bonds are ____ than the uncatalyzed, catalysis will occur
faster