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term 2 - BioChem unit 2 BT > Unit 6. Enzymes and coenzymes > Flashcards

Unit 6. Enzymes and coenzymes Flashcards

1
Q

The rate of the rxn is dependant on (5) things

A 
Reaction concentration 
temp 
pH - [H+] 
activation E (NRG barrier)
Product concentration
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2
Q

def:______: the cencentration of products cannot increase further

A

equilibrium state

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3
Q

What is Keq?

A

Equilibrium constant : [product]/[reactant]

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4
Q

Equilibrium constant can be calc. from _____ concentration or ratio of _____

A

equilibrium concentration
or
ratio of rate constants

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5
Q

______ must be greater than the NRG barrier for the rxn to proceed

A

activation NRG (Ea or delta G)

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6
Q

What is delta G?

A

activation NRG (Ea)

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7
Q

def: ____: when 2 reactants collide, NRG is released . It must be greater than the NRG barrier for the reaction to proceed

A

Activation NRG

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8
Q

_____: the amt of NRG required for the formation of products

A

Energy barrier

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9
Q

_____: how fast the products are formed

A

Reaction rate (or velocity) (v)

  • must be measured very early in reaction (before reverse reaction )
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10
Q

When must the reaction rate be measured ?

A

before the reverse reaction occurs

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11
Q

_____: the difference btw the initial free NRG of the reactants and the products

A

Gibbs Free ENERGY

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12
Q

What determines the final concentration of the reactants and products ?

A

Delta G

  • but not the reaction rate
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13
Q

If free NRG of product is lower than substrate the sign of Delta G will be ______ (+/-)

A

negative

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14
Q

If he free NRG of product is greater than substrate the sign of Delta G will be _____(+/-)

A

positive

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15
Q

______ effets the reaction rate

A

Activation NRG

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16
Q

_____ is when the product ends with less nrg than the initial reactant

A

exergonic

-Delta G

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17
Q

____ is when the product ends with more NRG than the initial reactant

A

endergonic

+Delta G

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18
Q

Standard state for : Moles, temp, pH and pressure

A

Moles: 1.0M
Temp: 25C or 298K
Pressure: 1atm
pH: 7.0

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19
Q

Is endergonic or exergonic spontaneous ?

A

exergonic

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20
Q

Catalyst ___ the rate of reaction

A

increase

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21
Q

Catalyst are ____ consumed

A

not

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22
Q

______ bind to substrate, lowering Ea

A

Catalyst

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23
Q

Can catalyst change Keq

A

No

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24
Q

Enzyme proteins can be _NA

A

RNA

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25
Q

The prosthetic group on an enzyme protein forms a _____

A

holoenzyme

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26
Q

If an enzyme protein prosthetic group is a metal it is a _______

A

metalloenzyme

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27
Q

_____ is an enzyme without a cofactor

A

apoprotein

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28
Q

An enzyme with optical specificity has the ability to __________

A

distinguish btw L- and D- forms of AA or sugars

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29
Q

Optical specificity is ________ specific

A

absolute

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30
Q

Specificity is dictated by the 3-D structure of the catalytic site of the enzyme and sunstrate it requires _______

A

3 point attachment

31
Q

_____: substrate induces a conformational change in the catalytic site

A

induced fit model

3 pt attachment

32
Q

Difference btw absolute and group specificity

A

absolute enzyme will only bind to one type of substrate (ex: fructokinase)

Grouped enzyme will bind to any type of substrate within a group (ex: hexokinase)

33
Q

def: _______site : binds the reactants and facilitates the reaction

A

catalytic site

34
Q

At least how many attachments must there be btw a substrate and enzyme

A

3 points of attachment

35
Q

def___: the substrate fits exactly into the enzyme active site

A

lock and key

36
Q

what are two models of substrate enzyme interactions

A

induced fit & lock and key

37
Q

____ : increase the rate of reaction

A

activator (stimulator) enzymes

38
Q

____: decreases the rate of reaction

A

inhibitor enzyme

39
Q

____ is an intermediate and products of metabolism

A

metabolites

40
Q

_______ compete with the natural metabolite for the active site of the enzyme

A

competitive inhibitors

41
Q

Competitive inhibitors can be overcome by the addition of more _____

A

substrate

  • Reversible
42
Q

Irreversible enzymes fxn?

A

eliminate enzyme fxn

43
Q

Name 5 properties of an enzyme

A
  1. catalyst
  2. proteins
  3. pH & tem dependent
  4. specific
  5. saturable
44
Q

____ are secondary substrates that are required for the catalytic actions of certain enzymes

A

coenzymes (cosubstrates)

45
Q

Vit. __ are coenzymes

A

Vit B

46
Q

____ are secondary substrates

A

coenzymes

47
Q

Coenzymes are required for the catalytic action of all enzymes T/F

A

false . only some

48
Q

coenzymes can be ____ derivatives

A

vitamin

49
Q

some ____ are covalently bound as prosthetic groups of enzymes

A

coenzymes

50
Q

Name (3) inorganic coenzymes

A

Ca+, Na+, Cl-

51
Q

Name (4) organic coenzymes

A

NAD?NADH
H+
FAD/FADH
CoASH

52
Q

_____: substances other than substrates which regulate an enzyme’s activity by binding to the allosteric site

A

allosteric effectors or ligands

53
Q

Allosteric effectors bind to _____ the regulate an enzymes activiry

A

allosteric site

54
Q

The binding of an activator or inhibitor ____ especially the catalytic site, altering the reaction rate _____

A

Changes the enzyme conformation

exponentially

55
Q

The main point of kinetics is to assess the ___ of an enzymatic reaction

A

velocity

56
Q

_______: measures the velocity of a reaction, with increasing substrate concentrations, keeping pH an d temp at optimum

A

michaelis-menten equation

57
Q

What factor is increased during a michaelis-menten equation

A

concentration of substrates

58
Q

Lower the Km value, the ___ the affinity of the substrate to the enzyme

(michaelis-menten equation )

A

greater

59
Q

Km = how strong of ___ an enzyme has for its substrate

michaelis-menten equation

A

affinity

60
Q

The greater the Km, the _____ the affinity of an enzyme for its substrate

(michaelis-menten equation)

A

lower

61
Q

_____ enzymes do redox reactions

A

oxidoreductase

62
Q

_____ enzymes transfer R-groups

A

transferase

63
Q

____ enzymes break substrates by addition of H2O

A

hydrolase

digestive enzymes

64
Q

All digestive enzymes are _____

A

hydrolase

65
Q

_____ enzymes break substrates w/o H2O

A

lyase

66
Q

____ enzymes convert isomers

A

isomerase

they rearrange molecules

67
Q

______ enzymes ligate with new covalent bonds

A

Ligase

synTHEtase/ synthase

68
Q

Ligate means to ___

A

join

69
Q

synTHEtase:______

A

uses ATP/GTP as NRG source

uses THE nrg

70
Q

Synthase:_______

A

uses other sources of NRG

besides ATP/GTP

71
Q

____: 2 or more enzymes that catalyze the same biochemical reaction

A

isozymes

72
Q

_____: a proenzyme or an enzyme precursor

A

zymogen

(ex: enzymes in bile are inactive when they are in the prancrease, and activate after they leave the pancrease … so they dont eat the pancreas)

73
Q

Isozymes are distinct, so they have _____AA sequences

A

different

and different physical properties

term 2 - BioChem unit 2 BT (3 decks)

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