Chp 5 Flashcards

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1
Q

Metabolism is the

A

buildup and breakdown of nutrients within a cell

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2
Q

These chemical reactions provide energy and create substances that sustain life

A

Metabolism

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3
Q

microbial metabolism can cause

A

disease and food spoilage, many pathways are beneficial rather than pathogenic

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4
Q

Catabolism

A

breaks down complex molecules; provides energy and building blocks for anabolism; exergonic

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5
Q

Anabolism

A

uses energy and building blocks to build complex molecules; endergonic

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6
Q

Metabolic pathways are

A

sequences of enzymatically catalyzed chemical reactions in a cell

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7
Q

Metabolic pathways are determined by

A

enzymes

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8
Q

Enzymes are encoded by

A

genes

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9
Q

The collision theory states

A

that chemical reactions occur when atoms, ions, and molecules collide

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10
Q

Activation energy

A

is the collision energy required for a chemical reaction to occur

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11
Q

Reaction rate

A

is the frequency of collisions containing enough energy to bring about a reaction

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12
Q

Reaction rate can be increased by

A

enzymes or by increasing temperature, pressure, or concentration

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13
Q

Catalysts

A

speed up chemical reactions without being altered

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14
Q

Enzymes are

A

biological catalysts

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15
Q

Enzymes act on a

A

specific substrate and lower the activation energy

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16
Q

Substrate contacts the enzyme’s active site to form an

A

enzyme-substrate complex

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17
Q

Substrate is transformed and rearranged into

A

products, which are released from the enzyme

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18
Q

Enzyme is unchanged and can react with other

A

substrates

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19
Q

Enzymes have specificity for

A

particular substrates

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20
Q

Turnover number is the

A

number of substrate molecules an enzyme converts to a product per second

Generally 1 to 10,000

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21
Q

Names of enzymes usually end in

A

ase

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22
Q

Naming enzymes

A

1) Oxidoreductase: oxidation-reduction reactions
2) Transferase: transfer functional groups

3) Hydrolase:
hydrolysis

4) Lyase: removal of atoms without hydrolysis
5) Isomerase: rearrangement of atoms
6) Ligase: joining of molecules; uses ATP

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23
Q

Enzyme Components

A

1) Apoenzyme: protein portion

2) Cofactor: nonprotein component
- –Coenzyme: organic cofactor

3) Holoenzyme: apoenzyme plus cofactor

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24
Q

Enzyme Components Assist

A

enzymes; electron carriers

example:
- Nicotinamide adenine dinucleotide (NAD+)
- Nicotinamide adenine dinucleotide phosphate (NADP+)
- Flavin adenine dinucleotide (FAD)
- Coenzyme A

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25
Q

Factors Influencing Enzyme Activity

A

1) Temperature
2) pH
3) Substrate concentration
4) Inhibitors

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26
Q

High temperature and extreme pH do what to enzyme activity

A

denature proteins

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27
Q

what happens to enzymes if the concentration of substrate is high

A

(saturation), the enzyme catalyzes at its maximum rate

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28
Q

increasing temperature does what to enzymatic activity

A

The enzymatic activity (rate of reaction catalyzed by the enzyme) increases with increasing temperature until the enzyme, a protein, is denatured by heat and inactivated. At this point, the reaction rate falls steeply.

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29
Q

Competitive inhibitors

A

fill the active site of an enzyme and compete with the substrate

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30
Q

Noncompetitive inhibitors

A

interact with another part of the enzyme (allosteric site) rather than the active site in a process called allosteric inhibition

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31
Q

Feedback Inhibition

A

End-product of a reaction allosterically inhibits enzymes from earlier in the pathway

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32
Q

Ribozymes

A

RNA that function as catalysts by cutting and splicing RNA

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33
Q

Oxidation:

A

removal of electrons

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34
Q

Reduction

A

gain of electrons

35
Q

Redox reaction

A

an oxidation reaction paired with a reduction reaction

36
Q

Biological oxidations are often

A

dehydrogenations

37
Q

In biological systems, electrons and protons are removed at

A

the same time; equivalent to a hydrogen atom

38
Q

ATP is generated by the

A

phosphorylation of ADP with the input of energy

39
Q

ATP generated when

A

added to ADP generates ATP

40
Q

Electrons are transferred from one electron carrier to another along an

A

electron transport chain (system) on a membrane that releases energy to generate ATP

41
Q

Photophosphorylation Occurs

A

only in light-trapping photosynthetic cells

42
Q

In Photophosphorylation Light energy is converted to

A

ATP when the transfer of electrons (oxidation) from chlorophyll pass through a system of carrier molecules

43
Q

Metabolic Pathways of Energy Production

A

Series of enzymatically catalyzed chemical reactions

Extracts energy from organic compounds and stores it in chemical form (ATP)

44
Q

Carbohydrate Catabolism is

A

The breakdown of carbohydrates to release energy

  • Glycolysis
  • Krebs cycle
  • Electron transport chain (system)
45
Q

Glycolysis

A

The oxidation of glucose to pyruvic acid produces ATP and NADH

46
Q

Glycolysis -Preparatory stage

A

2 ATP are used

Glucose is split to form two molecules of glyceraldehyde 3-phosphate

47
Q

Glycolysis -

Energy conserving stage

A
  • The two glyceraldehyde 3-phosphate molecules are oxidized to 2 pyruvic acid molecules
  • 4 ATP are produced
  • 2 NADH are produced
48
Q

In glycolysis Overall net gain

A

of two molecules of ATP for each molecule of glucose oxidized

49
Q

Additional Pathways to Glycolysis

A

Pentose phosphate pathway
and
Entner-Doudoroff pathway

50
Q

Pentose phosphate pathway to glycolysis

A
  • Uses pentoses and produces NADPH

- Operates simultaneously with glycolysis

51
Q

Entner-Doudoroff pathway

to glycolysis

A
  • Produces NADPH and ATP
  • Does not involve glycolysis
  • Occurs in Pseudomonas, Rhizobium, and Agrobacterium
52
Q

Cellular Respiration

A
  • Oxidation of molecules liberates electrons to operate an electron transport chain
  • Final electron acceptor comes from outside the cell and is inorganic
  • ATP is generated by oxidative phosphorylation
53
Q

Aerobic Respiration

A

Krebs cycle

Electron Transport Chain

Chemiosmosis

54
Q

Krebs cycle

A
  • Pyruvic acid (from glycolysis) is oxidized and decarboxylation (loss of CO2) occurs
  • The resulting two-carbon compound attaches to coenzyme A, forming acetyl CoA and NADH
55
Q

Krebs cycle is

Oxidation of

A

acetyl CoA produces NADH, FADH2, and ATP, and liberates CO2 as waste

56
Q

Electron transport chain (system) occurs in

A

the plasma membrane of prokaryotes; inner mitochondrial membrane of eukaryotes

57
Q

Electron transport chain series of

A

carrier molecules (flavoproteins, cytochromes, and ubiquinones) are oxidized and reduced as electrons are passed down the chain

58
Q

During the electron transport chain energy released is

A

used to produce ATP by chemiosmosis

59
Q

Chemiosmosis

A
  • Electrons (from NADH) pass down the electron transport chain while protons are pumped across the membrane
  • -Establishes proton gradient (proton motive force)

Protons in higher concentration on one side of the membrane diffuse through ATP synthase
–Releases energy to synthesize ATP

60
Q

During Aerobic Respiration The final electron acceptor in the electron transport chain is

A

molecular oxygen (O2)

61
Q

Carbohydrate Catabolism

A
  • Each NADH can be oxidized in the electron transport chain to produce 3 molecules of ATP
  • Each FADH2 can produce 2 molecules of ATP
62
Q

During anaerobic respiration The final electron acceptor in the electron transport chain is

A

NOT O2

Yields less energy than aerobic respiration

63
Q

Fermentation releases

A

energy from the oxidation of organic molecules

64
Q

Fermentation does not require

A

oxygen

65
Q

Fermentation does not use which cycles

A

Krebs cycle or ETC

66
Q

Fermentation Uses what molecule as the final electron acceptor

A

organic molecule

67
Q

Does fermentation Produce large or small amounts of ATP

A

small

68
Q

Lactic acid fermentation: produces

A

lactic acid

69
Q

two types of lactic acid fermentation are

A

1) Homolactic fermentation: produces lactic acid only

2) Heterolactic fermentation: produces lactic acid and other compounds

70
Q

in lactic acid fermentation glucose is oxidized to

A

pyruvic acid, which is then reduced by NADH

71
Q

Alcohol fermentation: produces

A

produces ethanol + CO2

Glucose is oxidized to pyruvic acid; pyruvic acid is converted to acetaldehyde and CO2; NADH reduces acetaldehyde to ethanol

72
Q

Lipid and Protien Catabolism stages

A

Protein
—extracellular proteases —>

Amino Acids
—-Deamination, decarboxylation, dehydrogenation, desulfurization—>

Organic Acid —->

Krebs Cycle

73
Q

Biochemical tests identify bacteria by

A

by detecting enzymes (e.g., those involved in decarboxylation and dehydrogenation)

74
Q

Fermentation test:

A

bacteria that catabolize carbohydrate or protein produce acid, causing the pH indicator to change color

75
Q

Oxidase test:

A

identifies bacteria that have cytochrome oxidase (e.g., Pseudomonas)

76
Q

Light-dependent (light) reactions:

A

conversion of light energy into chemical energy (ATP and NADPH)

77
Q

Light-independent (dark) reactions

A

ATP and NADPH are used to reduce CO2 to sugar (carbon fixation) via the Calvin-Benson cycle

78
Q

Photosynthesis is made up of what two kinds of reactions

A

light dependent reactions

light independent reactions

79
Q

Phototrophs use

A

light energy to metabolize

80
Q

Photoautotrophs use what in metabolism

A

energy in the Calvin-Benson cycle to fix CO2 to sugar

  • Oxygenic: produces O2
  • Anoxygenic: does not produce O2
81
Q

Photoheterotrophs use what compounds

A

use organic compounds as sources of carbon; anoxygenic

82
Q

Chemoautotrophs

A
  • Use energy from inorganic chemicals; CO2 as carbon source
  • Energy is used in the Calvin-Benson cycle to fix CO2
  • Use energy and carbon from organic chemicals
83
Q

Amphibolic pathways

A

:metabolic pathways that function in both anabolism and catabolism

-Many pathways function simultaneously with common intermediates