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B12 > Regulation of Enzymes (4.2) > Flashcards

Regulation of Enzymes (4.2) Flashcards

1
Q

State 3 factors that regulate enzymatic activity

A
  1. temp
  2. pH
  3. enzyme and substrate concentration
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2
Q

Describe temperature as a factor regulating enzymatic activity

A

Enzyme-catalysed reactions will generally increase as the temperature increases.

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3
Q

Describe the effect of cold temperatures on enzymatic activity

A

When enzymes fall below the optimal temperature, the rate of the reactions will slow down. Collision rate will also decrease and conformational changes will not occur.

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4
Q

Describe the optimal temperature range of human enzymes

A

36-38C

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5
Q

Describe the homeostatic temperature of humans

A

37C

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6
Q

State the optimal temperature of Taq polymerase

A

70C

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7
Q

Describe pH as a factor regulating enzymatic activity

A

If enzymes are taken too far above or below their optimal pH range, then the tertiary structure is affected and the substrate may not be able to bind.

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8
Q

Describe the effect of high temperatures on enzymatic activity

A

The hydrogen bonds and hydrophobic interactions of tertiary and quaternary structures are broken and enzyme shape will change so that the substrate cannot bind. The reaction won’t occur.

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9
Q

Describe the effect of non-ideal pH on enzymatic activity

A

If the reaction occurs in an environment in which the pH is not ideal, the micro-environment of the active site may provide a different pH to create a specific environment.

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10
Q

Describe the effect of enzyme and substrate concentration on enzymatic activity

A

The concentration of enzymes compared to substrates affects the rate of reactions.

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11
Q

Describe the effect of high enzyme concentration on reaction rate

A

High enzyme concentration compared to substrate will mean the reaction occurs over a short period of time

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12
Q

Describe the effect of low enzyme concentration on reaction rate

A

Low enzyme concentration compared to substrate will mean the reaction occurs over a long period of time

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13
Q

State 3 factors that determine if enzymes are able to catalyse reactions

A
  1. inhibition
  2. phosphorylation
  3. cofactors and coenzymes
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14
Q

State the 2 characteristics of enzyme inhibition

A
  1. reversible

2. irreversible

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15
Q

Describe reversible inhibition

A

Bonds formed between the inhibitor and enzymes are weak, so they are easily broken and inhibition reversed.

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16
Q

Describe irreversible inhibition

A

Bonds formed between the inhibitor and enzymes are strong, so the binding is irreversible.

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17
Q

Describe the effect of reversible inhibition on enzyme activity

A

Inhibitor can move in and out of the active site, which reduces the activity of the enzyme because its active site will not be available for the substrate to bind to as often.

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18
Q

Describe the effect of irreversible inhibition on enzyme activity

A

Inhibitor blocks all enzyme activity permanently and the enzyme will not be able to partake in reactions.

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19
Q

Describe the 3 major types of inhibition

A
  1. competitive
  2. non-competitive
  3. feedback
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20
Q

Describe competitive inhibition

A

Shape of the inhibitor is similar to substrate shape. As a result, inhibitors bind to enzyme active site and block the substrate.

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21
Q

Describe non-competitive inhibition

A

Allosteric inhibiton

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22
Q

Describe the allosteric site

A

Site on enzyme other than the active site to which an effector molecule binds

23
Q

Describe the 2 possible consequences of allosteric regulation

A
  • allosteric inhibition

- allosteric activation

24
Q

Describe allosteric inhibition

A

Inhibitor binds to an allosteric site which changes enzyme shape and prevents the substrate from binding.

25
Q

Describe allosteric activation

A

Some molecules that bind to allosteric sites can cause a conformational change that allows reactions to occur.

26
Q

Describe feedback inhibition

A

Product produced late in a pathway inhibits enzyme activity earlier in the pathway.

27
Q

Provide a step by step description of feedback inhibition and its’ effect on enzyme activity

A
  1. amount of inhibitors increase
  2. inhibitors bind to enzymes
  3. reduces amount of inhibitors
  4. less inhibitors bind to enzymes
  5. enzyme functions again
28
Q

Describe the effect of phosphorylation and dephosphorylation on enzyme activity

A

Phosphorylation and dehosphorylation can change protein structure

29
Q

Describe phosphorylation

A

Process of adding a phosphate group to a molecule

30
Q

Describe dephosphorylation

A

Reaction that involves the removal of a covalenty coupled phosphate group from another molecule.

31
Q

Describe the effect of cofactors on enzyme activity

A

Some enzymes require additional components that enable them to catalyse reactions.

32
Q

Describe the effect of coenzymes on enzyme activity

A

For certain enzymes, specific coenzymes are required to catalyse reactions

33
Q

Provide 3 examples of cofactors

A
  1. iron
  2. magnesium
  3. ATP
34
Q

Provide 3 examples of coenzymes

A
  1. ATP
  2. NADPH
  3. NADH
35
Q

State whether or not coenzymes are often structurally altered during reaction and whether or not they revert to their original form at reaction completion

A

Yes. Coenzymes are often structurally altered and revert to their original form once the reaction has been completed

36
Q

Describe what coenzymes ATP, NADH, NADPH, FADH2 act as

A

Metabolic intermediates

37
Q

Describe the role of metabolic intermediates

A

Carry chemical groups between different reactions

38
Q

Describe the role of metabolic intermediates in maintaining cellular processes

A

Store and transport chemical groups, protons and electrons from one reaction to another

39
Q

Describe the unloaded form of a coenzyme

A

Form of a coenzyme that is free to accept a proton, electron or chemical group

40
Q

Describe the loaded form of a coenzyme

A

Form of a coenzyme that has a proton, electron or chemical group to donate

41
Q

Describe what the cycling between loaded and unloaded coenzymatic forms is referred to as

A

Cycling of a coenzyme

42
Q

Describe chemical group

A

Group of covalently linked atoms

43
Q

Describe the role of ATP and ADP during reactions

A

Involved in energy transfer

44
Q

Describe what the breakdown of ATP to ADP results in

A

The release of energy stored in the bond between the third phosphate and ADP molecule

45
Q

Describe the role of NAD+/NADH

A

Involved in electron transfer

46
Q

Describe coenzyme

A

Organic molecule that combines with an enzyme and supports activity

47
Q

Describe cofactor

A

Chemical component that is required for the proper function of proteins

48
Q

Describe saturation point

A

Maximum rate of reaction where increasing the enzyme or substrate concentration further does not affect the reaction rate.

49
Q

Describe an oxidation reaction

A

Occurs when a coenzyme donates an electron

50
Q

Describe a reduction reaction

A

Occurs when a coenzyme accepts electrons

51
Q

Describe how coenzymes are involved in oxidation and reduction reactions

A

Coenzymes are involved in the transfer of electrons between reaction or biochemical pathways

52
Q

State whether or not AUG is the starting amino acids for all functional proteins.

A

No. There are some rare exceptions

e.g. Fungus Candida albicans

53
Q

State whether or not introns or extrons are spliced out during RNA processing

A

Introns are spliced. Exons are expressed as proteins or RNA and form mRNA strand.

B12 (41 decks)

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