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Completed > Ch 8 Microbial Metabolism > Flashcards

Ch 8 Microbial Metabolism Flashcards

0
Q

What is a metabolic pathway

A

Sequence of chemical reactions each catalyzed by a particular enzyme; anabolic and catabolic

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1
Q

Define metabolism

A

The sum total of all energy exchanges that occur in cells

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2
Q

What is an anabolic pathway

A

Consume energy to build larger more complex molecules from simpler ones; can be called biosynthetic pathways; “uphill pathways”

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3
Q

Catabolic pathway

A

Release energy by breaking down more complex molecules into simpler ones; “downhill pathways”

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4
Q

What is free energy

A

The portion of a system’s energy that can perform work

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5
Q

Exergonic reaction

A

Proceeds with a net release of free energy; spontaneous reactions; “downhill reactions” products have less free energy than the reactants; catabolic

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6
Q

Endergonic reactions

A

One that absorbs free energy from its surroundings; non-spontaneous reactions; “uphill reactions” products have more free energy than the reactants

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7
Q

ATP is made up of what two things

A

Nucleotide and inorganic phosphate groups (Pi)

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8
Q

What three things make up a nucleotide

A

Nitrogenous base, ribose, phosphate group

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9
Q

Which nitrogenous base is found in ATP

A

Adenine (which is a purine)

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10
Q

What is Phosphorylation

A

Addition of a Pi (an inorganic phosphate group)

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11
Q

Phosphorylation of ADP would form ____ and is a _____ reaction

A

ATP; it is an endergonic reaction

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12
Q

Hydrolysis

A

Release of a Pi (inorganic phosphate group)

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13
Q

Hydrolysis of ATP would form ____ and is a _____ reaction

A

ADP; is and exergonic reaction

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14
Q

Phosphorylated intermediate

A

Formed from ATP transferring a phosphate group to a specific reactant; becomes more reactive-less stable

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15
Q

Enzymes

A

A macromolecule, usually a protein that acts as a catalyst; have very specific shapes, are globular proteins and are not consumed in a reaction so they can be used repeatedly

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16
Q

Catalyst

A

A chemical agent that speeds up a reaction without being consumed by the reaction

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17
Q

What is the activation energy barrier

A

Amount of energy needed to push the reactants to the top of an energy barrier or uphill so the downhill part of the reaction can occur

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18
Q

What do enzymes do to the amount of activation energy required

A

Enzymes lower the activation energy required

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19
Q

Transition state

A

The molecules have absorbed enough activation energy and their bonds can be broken and then reformed into the more stable bonding arrangements

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20
Q

What is the active site of an enzyme

A

Typically a pocket or groove on the surface of the enzyme where catalysis occurs

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21
Q

What is a substrate

A

The reactant of an enzyme catalyzed reaction

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22
Q

What is an enzyme-substrate complex

A

Formed when an enzyme binds to it’s substrates

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23
Q

Name five factors that affect enzyme activity

A

Temperature, pH, cofactors, coenzymes, inhibitors

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24
Q

What are cofactors

A

Any nonprotein molecules or ion that is required for the proper functioning of an enzyme. Can be permanently bound to the active site or bind loosely and reversibly along with the substrates

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25
Q

Examples of cofactors

A

Inorganic; metal ions; Ex: Fe2, Mg2

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26
Q

What are coenzymes

A

An organic molecule serving as a cofactor

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27
Q

Examples of coenzymes

A

Organic; most are vitamins; Ex: NAD, FAD, CoA, CoQ, and cytochromes

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28
Q

What are inhibitors? name 2 types

A

Reduce the productivity of enzymes; competitive and noncompetitive

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29
Q

Describe competitive inhibitors

A

Reduce the productivity of enzymes by blocking substrates from entering active sites; directly competes with substrates for binding to the active site

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30
Q

Describe noncompetitive inhibitors

A

Do not directly compete with the substrate to bind to the enzyme and active site; binds to another part of the enzyme

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31
Q

What is oxidation

A

Loss of electrons and hydrogen ions(H+)

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32
Q

What is reduction

A

Gain of electrons and hydrogen ions(H+)

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33
Q

LEO the lion says GER

A 
Lose
Electrons
Oxidation
Gain
Electrons
Reduction
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34
Q

What is an internal acceptor?

A

An organic molecule that is an intermediate product in the catabolic pathway

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35
Q

What is the name of the catabolic pathway with an internal electron acceptor

A

Fermentation

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36
Q

What is an external electron acceptor

A

Other electronegative molecules not produced in the catabolic pathway

37
Q

What is the name of the catabolic pathway in which an external electron acceptor is used

A

Respiration

38
Q

Name two types of respiration and their final external electron acceptor

A

Aerobic respiration: catabolic pathway, oxygen

Anaerobic respiration: catabolic pathway, non-oxygen

39
Q

What are cytochromes

A

Transmembrane proteins in the electron transport chain

40
Q

Name the four metabolic stages of aerobic or anaerobic respiration

A

Glycolysis, pyruvate oxidation, citric acid cycle, oxidative phosphorylation

41
Q

Where does glycolysis occur

A

In the cytoplasm

42
Q

Where does pyruvate oxidation occur

A

In the cytoplasm

43
Q

Where does the citric acid cycle occur

A

In the cytoplasm

44
Q

Where does oxidative phosphorylation occur

A

At the cell membrane

45
Q

Two activities that occur during oxidative phosphorylation

A

Electron transport chain and Chemiosmosis

46
Q

What is glycolysis

A

The splitting of sugar. Partial oxidation of glucose to a three carbon intermediate product

47
Q

Describe the energy investment phase of glycolysis

A

Invest 2 ATP, produce 2 G3P (a 3 carbon sugar)

48
Q

Describe the energy payoff phase of glycolysis

A

Yield 4 ATP, produce 2 pyruvate, 2 NADH+

49
Q

What is the 3 carbon intermediate product of glycolysis called

A

Pyruvate

50
Q

What is substrate level phosphorylation

A

The enzyme catalyzed formation of ATP by direct transfer of a Pi to ADP from an intermediate substrate in catabolism

51
Q

What are the NET products of glycolysis

A

2 ATP
2 NADH
2 pyruvate

52
Q

During pyruvate oxidation what happens for EACH pyruvate

A

CO2 is given off and pyruvate is oxidized to form acetyl which combines with CoA to form acetyl-CoA. NAD is reduced to form NADH.

53
Q

What are the NET products of pyruvate oxidation

A

2 CO2
2 NADH
2 Acetyl-CoA

54
Q

During the citric acid cycle explain how to get from acetyl-CoA to citrate

A

Each acetyl-CoA enters the citric acid cycle by joining with a 4 carbon molecule of oxaloacetate (OA) to form a 6 carbon IP called citrate. CoA departed.

55
Q

How many carbons are left at the end of the citric acid cycle and why

A

Cycle will completely oxidize the carbon compounds recycling back into the OA receiver; CO2 is given off, so NO carbons continue into the next phase.

56
Q

How is ATP produced during the citric acid cycle

A

By using substrate level phosphorylation (SLP)

57
Q

What are the NET products of the citric acid cycle

A

4 CO2
2 ATP
6 NADH
2 FADH2

58
Q

During the citric acid cycle which IP is oxidized

A

Citrate

59
Q

What happens during the first step of the electron transport chain

A

NADH & FADH deliver the electrons and H+ to the transmembrane proteins (cytochromes) to the ETC.

60
Q

What is the second step in the electron transport chain

A

Electrons move from one carrier to another in the chain. The transfer of electrons occurs from a carrier with less electronegativity to a carrier that has more EN

61
Q

The ETC is a ______ reaction resulting in a ______ of free energy

A

Spontaneous downhill reaction resulting in a release of free energy

62
Q

What is the final electron acceptor in the ETC during aerobic respiration?

A

Oxygen

63
Q

What happens at the final electron acceptor in the ETC

A

As oxygen receives the electrons and combines with 2 H+ a molecule of water is formed

64
Q

If the final electron acceptor was not oxygen what would the process be called

A

Anaerobic respiration

65
Q

What happens to the free energy released from the ETC

A

Is used to power proton pumps embedded in the cell membrane

66
Q

Proton pumps embedded in the cell membrane pump protons (H+) out of the ______ into the ______

A

Proton pumps embedded in the cell membrane pump protons out of the cytoplasm into the periplasmic space

67
Q

The pH of the cytoplasm will be ______ compared to the _____ pH of the periplasmic space

A

The pH of the cytoplasm will be low compared to the high pH of the periplasmic space

68
Q

Explain the proton motive force

A

The electrochemical gradient created by the proton pumps; source of potential energy to power the chemiosmosis that will follow

69
Q

Explain how chemiosmosis works

A

Protons flow back through the cell membrane to relieve the proton motive force gradient through a channel protein/enzyme called ATP synthase

70
Q

What does ATP synthase do

A

Harnesses the proton motive force energy to phosphorylate ADP to form ATP

71
Q

What are the NET products of the ETC

A

10 NAD+
2 FAD
6 H2O

72
Q

What are the NET products of chemiosmosis

A

3 ATP per NADH = 30 ATP
2 ATP per FADH2 = 4 ATP
TOTAL = 34 ATP

73
Q

Explain the difference between aerobic respiration and anaerobic respiration

A

Anaerobic respiration follows the same metabolic pathway as aerobic except that a non-oxygen final electron acceptor is used. Products are variable and ATP yields are much less

74
Q

Name the three non-oxygen final electron acceptors used in anaerobic respiration

A

Nitrate, sulfate, carbonate

75
Q

What is the product when nitrate is reduced during anaerobic respiration

A

Nitrogen gas + ammonia + 4 ATP

76
Q

What is the product of sulfate reduction using anaerobic respiration

A

Hydrogen sulfide + 3 ATP

77
Q

What is the product of carbonate reduction in anaerobic respiration

A

Methane + 2 ATP

78
Q

What is the internal electron acceptor used for fermentation

A

Pyruvate

79
Q

During fermentation ____ gets reduced and ______ gets oxidized

A

During fermentation pyruvate gets reduced and NADH gets oxidized

80
Q

Acid fermentation produces what

A

Lactic acid or mixed acids

81
Q

Alcohol fermentation produces what

A

Ethyl alcohol (ethanol) + CO2

82
Q

What is the first step of fermentation

A

Glycolysis

83
Q

What is the function of fermentation

A

To regenerate the NADs to allow glycolysis to continue

84
Q

How many carbons does G3P have

A

3

85
Q

How many carbons does pyruvate have

A

3

86
Q

How many carbons does oxaloacetate (OA) have

A

4

87
Q

How many carbons does citrate have

A

6

88
Q

How many carbons does acetyl-CoA have

A

2

89
Q

How many NADH and FADH2 arrive at the ETC

A

10 NADH

2 FADH

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