Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT > Enzymes > Flashcards

Enzymes Flashcards

You may prefer our related Brainscape-certified flashcards:
MCAT flashcards
1
Q

Enzyme effect on activation energy

A

Lowers it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Enzyme effect on reaction rate

A

Increases it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Enzyme effect on equilibrium constant

A

No effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Is an enzyme used in a reaction?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Enzymes must have ________ to function.

A

Optimal temperature and ph ranges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Enzyme effect on free gibbs energy

A

No effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do enzymes know which reaction to catalyze?

A

They are specific for reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Oxidoreductases

A

They catalyze oxidation-reduction reactions by transferring electrons. They usually have cofactors to carry electrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Reductant

A

Donates electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Oxidant

A

Accepts electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Transferases

A

They catalyze the transfer of functional groups from one molecule to another. Kinases are an example and they transfer phosphate from ATP to a molecule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Hydrolyase

A

They break down compounds by adding water. Examples include phospotases, peptidases, lipases, and nucleases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Lyase

A

Cleave single molecule into two without adding water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Synthase

A

Make compound by joining two molecules; reverse action of lyase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Isomerase

A

They rearrange bonds in a molecule. They can be oxidoreductases, transferases, and lyases. They can do reactions between stereoisomers as well as consituitional isomers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Ligases

A

Synthesis of large molecules and often require ATP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Endergonic

A

Free gibbs energy of products is higher and reaction requires energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Exergonic

A

Free gibbs energy of products is lower and reaction releases energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many copies of an enzyme do you need for a reaction?

A

You don’t much because they do not get used up in reactions and can be reused.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Enzymes lower the activation energy to get to _______

A

transition state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Active site

A

Site on enzyme where substrate is held

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does a substrate know which enzyme to bind to?

A

The active site has a defined spatial arrangement that dictates specificity of that enzyme for a substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What interactions stabilize the active site?

A

Hydrogen bonding, ionic bonding, transient covalent bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Lock and key theory

A

Enzyme is lock and substrate is key. There is no change in tertiary and quaternary structure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Induced model fit

A

Substrate and enzyme do not seem to fit. Substrate induces a conformational change in the enzyme which requires energy. When the substrate is released, energy is released.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

According to the induced model fit, what will happen to the enzyme if the wrong substrate tries to bind to it?

A

No conformation change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Cofactors and conezymes

A

They are small, bind to the active site of an enzyme, can carry charge, and usually there is a low concentration of them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Apoenzymes

A

Enzymes without cofactors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Haloenzymes

A

Enzymes with cofactors

30
Q

Cofactors

A

Inorganic molecules e.g. metal ions

31
Q

Coenzymes

A

Small organic molecules, mostly vitamins

32
Q

Saturation

A

When all active sites are occupied.

33
Q

What will happen to Vmax if more substrate is added?

A

Nothing will happen because all active sites are occupied

34
Q

How do you raise Vmax?

A

Increase enzyme concentration by increasings its gene expression

35
Q

Michaelis-Menten Equation

A

Look this up for clear picture buts its V=(Vmax*[S])/(Km+[S])

36
Q

What is V when Km=[S]

A

V=0.5Vmax

37
Q

Km

A

Substrate concentration at which 0.5 of enzyme active sites are full

38
Q

Low Km

A

Enzyme has higher affinity for substrate

39
Q

High Km

A

Enzyme has lower affinity for substrate

40
Q

Vmax equation

A

Vmax=[E]kcat

41
Q

Kcat

A

Number of substrate molecules “turned over” into product

ES –> E+P

42
Q

Catalytic efficiency

A

Kcat/Km

43
Q

Lineweaver burk plots

A

Linear version of Michaelis-Menten equation. It is 1/[S] vs 1/v. The x and y intercepts represent the 1/vmax and 1/kmax.

44
Q

[S] vs V shape for cooperativity

A

Sigmoidal

45
Q

T

A

Low affinity tense state

46
Q

R

A

High affinity relaxed state

47
Q

Hill’s coefficient

A

Measures cooperativity

48
Q

Hills cooefficient < 1

A

Negative cooperativity

49
Q

Hill’s coefficient > 1

A

Positive cooperativity

50
Q

Hill’s coefficient = 1

A

No cooperativity observed

51
Q

Human temperature

A

37 C, 98.6 F, 310 K

52
Q

What happens to enzyme activity as temperature increases?

A

Activity increases but after certain temperature, the enzyme starts to denature and so activity lowers.

53
Q

What happens to enzyme activity is there is change in pH?

A

It lowers because enzymes denature.

54
Q

What happens to enzyme activity if there is change in [salt] in vitro?

A

This disrupts hydrogen and ionic bonds and change in enzyme structure and denaturation.

55
Q

Feedback regulation

A

Enzymes regulated by products made later

56
Q

Forward regulation

A

Enzymes regulated by products made before

57
Q

Negative feedback

A

Enough product created so turn off synthesis pathway; product may bind to active site and compete with substrates

58
Q

Competitive inhibition, it’s effects on Vmax and Km

A

Substrates cannot access actives site if inhibitor is in the way

  • Vmax does not change
  • Km increases because you have to add more S
59
Q

How can you overcome competitive inhibition?

A

By increasing [S] so S is more likely to encounter E rather than the competitive inhbitor

60
Q

Noncompetitive inhibitor, its effects on Vmax and Km

A

It binds to allosteric site on enzyme which induces enzyme conformational and substrate is unable to bind.

  • Vmax decreases
  • Km does not change because adding [S] won’t do anything
61
Q

Mixed inhbition

A

Has unequal affinity for enzyme or enzyme-substrate complex
Binds to allosteric site
If it binds to enzyme, Km increases and Vmax decreases
If it binds to complex, Km decreases and Vmax decreases

62
Q

Uncompetitive inhibitor

A

It binds to allosteric sites on enzyme-substrate complex and increases affinity for substrate and so enzyme complex does not release it. Kmax decreases and so does Vmax

63
Q

How do you overcome irreversible inhibition?

A

Make new copies of enzyme to get function back

64
Q

Irreversible inhbition

A

Enzyme permanently altered or not easily reversible.

65
Q

Allosteric sites

A

Binding here affects affinity of binding sites

66
Q

Allosteric activators

A

Make the active site for available

67
Q

Allosteric inhibitors

A

Inhibit active site

68
Q

Zymogen

A

They have catalytic (active) domain and regulatory domain. Regulatory domain must be altered to expose active site.

69
Q

Which has more affinity? A cooperative enzyme or cooperative enzyme with substrate bound?

A

In cooperative enzymes, as susbtrates bind, cooperativity (+ or -) increases so an unbound nezyme has less afinity than one bound to one < 2< 3

70
Q

Can triglycerides be cofactors?

A

No, they are too big.

71
Q

What happens to ideal temperature if a catalyst is added to a reaction?

A

It is lowered

MCAT (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions