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Biology > Chapter 7 - Metabolic Components > Flashcards

Chapter 7 - Metabolic Components Flashcards

1
Q

What is a catalyst?

A

any substance which can provide an alternative route or an alternative transition state (they lower the transition state’s activation energy)

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2
Q

How can a competitive inhibitor be overcome?

A

It can be overcome at high concentrations of substrate.

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3
Q

Lineweaver-Burk plot of mixed inhibition

A
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4
Q

What is a mixed inhibitor?

A

a molecule that can bind the free enzyme or the enzyme-substrate complex, but has a greater affinity for one state over another (this specifically is how it differs from a non-competitive inhibitor)

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5
Q

Michaelis-Menten kinetics graph

A

Beginning of graph: rate depends on [S] (first order)

End of graph: rate depends on [E] (zero order)

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6
Q

Coenzyme A structure

A
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7
Q

Lineweaver-Burk plot of competitive inhibition

A
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8
Q

In the reaction A –> B, if k1 > k2, then at equilibrium how do their concentrations differ?

A

[B] > [A]

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9
Q

Where is the phosphomonoester linkage in ATP?

A

between the C5’ of the ribose ring and the first phosphate group

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10
Q

What is the active site of an enzyme?

A

the specific site to which a specific substrate molecule will bind

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11
Q

What is a competitive inhibitor?

A

a molecule that resembles the normal substrate and can readily bind the active site of the enzyme to form an enzyme-inhibitor complex (EI)

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12
Q

In competitive inhibition, what is the effect on Vmax?

A

It is unchanged - initially, there is a lower Vmax for a given substrate concentration, but as substrate concentration increases, [I] becomes negligible and the same Vmax can be reached.

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13
Q

Lineweaver-Burk plot of non-competitive inhibition

A
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14
Q

What are the 3 main active residues in chymotrypsin’s active site (catalytic triad)?

A

serine, histidine, aspartic acid

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15
Q

Lineweaver-Burk kinetics plot

A
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16
Q

Michaelis-Menten graph of competitive inhibition

A
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17
Q

NAD structure

A
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18
Q

Where is the phosphoric anhydride linkage in ATP?

A

between each phosphate group

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19
Q

Michaelis-Menten graph of non-competitive inhibition

A
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20
Q

What is the active site of coenzyme A?

A

a sulfhydryl group (-SH)

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21
Q

What is the shape of the Michaelis-Menten graph?

A

hyperbolic

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22
Q

What is convergent evolution?

A

Molecules/organisms that are similar evolved independently of each other, but are similar due to the environment.

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23
Q

General reaction for an enzyme + substrate

A

E + S <—> ES —> E + P

k1: E + S –> ES

k2: E + S <– ES

k3: ES –> E + P

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24
Q

Describe the general mechanism of chymotrypsin

A
  • At physiologic pH, aspartic acid is deprotonated. It makes its neighbor Histidine more basic. As a result, Histidine can deprotonate its neighbor Serine to form an alkoxide ion.
  • In the presence of an ester/peptide, Serine’s alkoxide ion can attack the carbonyl carbon, forming an unstable tetrahedral intermediate. The electrons reform the carbonyl, kicking off the amino group.
  • Water enters, and is deprotonated by Histidine. The OH attacks the carbonyl, again forming an unstable tetrahedral intermediate. The electrons reform the carbonyl, kicking off the bond to Serine, and allowing the new acid to leave the enzyme.
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25
Q

Michaelis-Menten kinetics curve for allosteric enzymes

26
Q

FAD structure

27
Q

What are the three main components of adenosine triphosphate (ATP)?

A

- 3 phosphate groups

Adenosine:

- adenine

- D-ribose

28
Q

We must have enough ___ in our diet to synthesize NAD?

A

tryptophan (essential amino acid)

29
Q

Equation: Lineweaver Burk rate equation

A

1/V = [KM/Vmax][1/S] + 1/Vmax

30
Q

In competitive inhibition, what is the effect on KM?

A

The apparent KM increases.

31
Q

What is a ribozyme?

A

An RNA enzyme that catalyzes specific reactions. They were the first discovered catalytic RNA molecule.

32
Q

Where is the N-acetal/N-glycosidic linkage in ATP?

A

C1’ of the ribose ring and N9 the adenine ring

33
Q

In uncompetitive inhibition, what is the effect on Vmax?

A

Vmax is reduced.

34
Q

How can non-competitive inhibition be overcome?

A

It cannot be overcome.

35
Q

What is flavin adenine dinucleotide (FAD)?

A

a coenzyme

36
Q

In the Lineweaver-Burk plot, what is the y-intercept?

37
Q

What is Vmax?

A

It is the rate obtained when all the enzyme’s active sites are saturated with subtrate.

38
Q

What is divergent evolution?

A

Molecules/organisms that have similar makeup because of a related ancester.

39
Q

What is the relationship between chymotrypsin, chymotrypsinogen, and trypsin?

A

Trypsin cleaves the inactive chymotrypsinogen into active chymotrypsin.

40
Q

What is a non-competitive inhibitor?

A

A molecule that does not compete at the active site of an enzyme, but rather binds to some other site on the enzyme or enzyme-substrate complex (allosteric site), altering the conformation of the enzyme, reversibly inactivating the active site.

41
Q

Lineweaver-Burk plot of uncompetitive inhibition

42
Q

What is anabolism?

A

The component of metabolism that builds complex molecules and uses energy.

43
Q

In the Lineweaver-Burk plot, what is the x-intercept?

44
Q

What is an uncompetitive inhibitor?

A

a molecule that binds to the enzyme-substrate complex

45
Q

Graph of catalyzed reaction vs. uncatalyzed reaction

46
Q

Equation: Michaelis-Menten rate equation

A

V = Vmax[S]/([S] + KM)

47
Q

What does a curved Lineweaver-Burk plot indicate?

A

The enzyme is multimeric and binds more than one molecule of substrate.

48
Q

What are transition state analogs?

A

They are synthesized molecules that look like the transition states of certain reactions. They are competitive inhibitors of reactions.

49
Q

In non-competitive inhibition, what is the effect on Vmax?

A

It lowers Vmax. There concentration of active enzymes is smaller.

50
Q

Why does hydrolysis of phosphoric anhydride linkages release so much energy?

A

the products can be stabilized by resonance

51
Q

In non-competitive inhibition, what is the effect on KM?

A

KM remains unchanged. Enzymes that have not encountered the non-competitive inhibitor still have the same KM.

52
Q

In a Lineweaver-Burk plot, what is the slope equation?

A

slope = KM/Vmax

53
Q

What is meant by KM? What about a high value vs. low value?

A

It is equal to the substrate concentration at which the reaction rate is half of its maximal value.

When [S] = KM, then V = Vmax/2

High KM indicates a weak binding of the ES complex, while a low KM indicates a strong binding of the ES complex.

54
Q

What is catabolism?

A

The component of metabolism that breaks down complex molecules into simpler products accomponied by the release of energy (ATP).

55
Q

What are the two main ways you can get reactants/products to cross through a high-energy transition state

A
  • raise the temperature (give them sufficient energy)
  • use a catalyst (lower the activation energy)
56
Q

What is the role of chymotrypsin and what is its enzyme classification?

A

It catalyzes the hydrolysis of either ester or peptide bonds (C-terminus of aromatic amino acids). It is a serine protease.

57
Q

What is a proenzyme/zymogen?

A

inactive precursor of an enzyme

58
Q

In uncompetitive inhibition, what is the effect on KM?

A

KM is reduced.

59
Q

Which portion of nicotinamide adenine dinucleotide (NAD) is used by an enzyme’s active site?

A

the nicotinamide (the rest of the molecule is held within the enzyme, anchoring the cofactor)

60
Q

What are coenzymes?

A

non-amino acid, non-polypeptide, non-protein sybstance which is required fo the activity of an enzyme

Biology (9 decks)

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