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Microbiology > Lecture 4 and 5 Microbial Metabolism > Flashcards

Lecture 4 and 5 Microbial Metabolism Flashcards

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1
Q

What is metabolism?

A

Sum of chemical reactions in a cell

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2
Q

What are the two parts of metabolism?

A

Catabolism, anabolism/biosynthesis

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3
Q

What is catabolism

A

Processes that degrade compounds to release energy
- cells capture to make ATP

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4
Q

What is anabolism?

A

Assemble subunits of macromolecules
uses ATP to drive reactions

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5
Q

What is energy?

A

Capacity to do work

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6
Q

What is potential energy?
(chemical bonds, rock on a hill, water behind a dam)

A

Stored energy

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7
Q

What is kinetic energy?

A

Energy of motion

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8
Q

Photosynthetic organisms harvest energy in sunlight
- power synthesis of organic compounds from ______
- converts kinetic energy of _____ to potential energy of ____

A

CO2

photons, chemical bonds

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9
Q

_______ obtain energy from organic compounds

A

Chemoorganotrophs

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10
Q

Chemoorganotrophs depend on activities of ______

A

Chemolithoautotrophs

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11
Q

What is free energy?

A

Energy available to do work
- released when a chemical bond is broken

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12
Q

What is exergonic reactions

A

When reactants have more free energy than products

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13
Q

Is energy released in exergonic reactions?

A

yes

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14
Q

Endergonic reactions

A

Products have more free energy than reactants

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15
Q

In an endergonic reaction, the reaction requires what?

A

An input of energy

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16
Q

Change in free energy is the ______ regardless of number of steps involved

A

Same

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17
Q

Cells use multiple steps when _________ compounds

A

degrading

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18
Q

Energy released from _____ reactions power ______ reactions

A

Exergonic, endergonic

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19
Q

Metabolic pathway

A

Series of reactions that converts starting compounds to a product

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20
Q

Metabolic pathways may be….

A

Linear, branched, cyclical

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21
Q

What is the role of biological catalysts

A

Speeds up conversion of substrate into a product by LOWERING activation energy

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22
Q

What is ATP long form

A

Adenosine triphosphate

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23
Q

What is ATP

A

Energy currency of a cell

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24
Q

What is ATP composed of?

A

Ribose, adenine, three phosphate groups

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25
Q

Cells use energy to produce ATP by adding Pi to what?

A

Adenosine disphosphate (ADP)

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26
Q

How is energy released in a metabolic pathway?

A

removing Pi from ATP to yield ADP

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27
Q

What is substrate level phosphorylation?

A

energy generated in exergonic reactions

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28
Q

What process do some bacteria, especially steptococci, get their energy from?

A

Substrate-level phosphorylation

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29
Q

What is oxidative phosphorylation

A

Energy generated by proton motive force

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30
Q

What type of organisms use substrate level phosphorylation and oxidative phosphorylation

A

Chemoogranotrophs

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31
Q

What is photophosphorylation?

A

Sunlight used to create proton motive force

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32
Q

What type of organisms use photophosphorylation?

A

Photosynthetic organisms

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33
Q

What is an electron that has a low affinity for electrons called

A

energy source

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34
Q

What is a molecule that has a high affinity for electrons called

A

Terminal electron acceptor

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35
Q

How is energy release in terms of affinity?

A

electrons move from a molecule that has a low affinity to a molecule that has a high affinity
AKA energy source to terminal electron acceptors

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36
Q

More energy is released when the difference in ______ is greater

A

Electronegativity

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37
Q

Electronegativity is the same as ______

A

Affinity for electrons

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38
Q

Prokaryotes use diverse energy sources and ______

A

terminal electron acceptors

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39
Q

In prokaryotes, what compounds are used as energy soruce?

A

inorganic compounds

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40
Q

In prokaryotes, what compounds are used as terminal electron acceptors?

A

O2 and other moecuels

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41
Q

Electrons are removed through what process?

A

Redox reactions

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42
Q

Substances that loses electrons is ______

A

Oxidized

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43
Q

Substances that gains electrons is ______

A

Reduced

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44
Q

______ is transferred in a redox reaction

A

Electron proton pair or hydrogen atoms

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45
Q

What is dehydrogenation?

A

oxidation

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46
Q

What is hydrogenation?

A

Reduction

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47
Q

Electrons are initially transferred to what?

A

electron carriers

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48
Q

What are common electron carriers?

A

NAD/NADH, NADP/NADPH, FAD/FADH2

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49
Q

Reduced electron carriers represent what power?

A

Reducing

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50
Q

What is the role of reduced electron carriers?

A

Easily transfer electrons to chemicals with HIGHER affinity for electrons/electronegativity

Raise energy level of recipient molecules

drive synthesis of ATP or biosynthesis

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51
Q

What occurs in central metabolic pathways?

A

Oxidized glucose molecules generate ATP, reducing power (NADH, FADH2 and NADPH) and precursor metabolites

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52
Q

Transferring the electrons carried by NADH and FADH2 to the terminal electron acceptor which is done by either ________ or ________

A

cellular respiration or fermentation

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53
Q

What do central metabolic pathways do?

A

Oxidize glucose to CO2

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54
Q

The catabolic, but precursor metabolites and reducing power can be also used in biosynthesis
- this means it is called ________ because of dual role

A

Amphibolic

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55
Q

What does glycolysis do?

A

Splits glucose to two pyruvate molecules

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56
Q

What does glycolysis generate?

A

ATP, reducing power, precursors

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57
Q

What is the role of pentose phosphate patway?

A

production precursor metabolites, NADH

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58
Q

What does tricarboxylic acid (TCA) cycle do?

A

Oxidizes pyruvate, release CO2

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59
Q

What does TCA cycle generate?

A

Reducing power, precursor metabolites, ATP

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60
Q

What process transfers electrons from glucose to ETC to terminal electron acceptor?

A

Cellular respiration

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61
Q

What does electron transport chain generate?

A

proton motive forces

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62
Q

In aerobic respiration, what is the terminal electron acceptor?

A

O2

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63
Q

In anaerobic respiration, what is the terminal electron acceptor?

A

Molecule other than O2

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64
Q

Anaerobic respiration is a modified version of what?

A

TCA cycles

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65
Q

What does fermentation do?

A

recycles electron carriers in a cell that cannot respire so that it can continue to make ATP

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66
Q

What is the terminal electron acceptor in fermentation process?

A

Pyruvate or derivate
- receives H from NADH

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67
Q

Fermentation regenerates NAD so that

A

glycolysis can continue

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68
Q

What does glycolysis provide

A

small amount of ATP

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69
Q

What are enzymes and what do they do?

A

biological catalysts, increase the rate of a reaction

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70
Q

enzymes are highly specific ________
enzymes are not changed by a reaction so a single molecules can be used ________

A

substrates
again and again

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71
Q

________ on surface of enzymes binds substrates weakly

A

active site

72
Q

What does the enzyme fitting in an active sit result in?

A

enzyme substrate complex that destabilizes existing bond or allows new ones to form

73
Q

What does the enzyme substrate complex do to the activation energy?

A

lowers in

74
Q

enzyme- catalyzed reactions are ________

A

reversible
- but free energy of some reactions prevents reversibility

75
Q

What assists different enzymes?

A

cofactors

76
Q

What are common cofactors?

A

magnesium, zinc, copper

77
Q

What are coenzymes

A

Organic cofactors

78
Q

What are examples of coenzymes

A

electron carriers FAD, NAD, NADP
-derived from enzymes

79
Q

What are environmental factors that influence enzyme activity

A

Temp, pH, salt concentration

80
Q

What happens to proteins at high temperatures?

A

They denature

81
Q

What is the optimum condition for most enzymes?

A

Low salt, neutral pH

82
Q

What does 10 degrees celsius increase do to the speed of enzyme reaction?

A

Doubles speed

83
Q

What is allosteric regulation?

A

enzyme activity controlled by regulatory molecules binding to allosteric site

84
Q

What does allosteric regulation do the the enzyme shape and binding of substrate to active site?

A

Distorts enzyme shape
Prevents or enhances binding of substrate

85
Q

What is the regulatory molecule in a metabolic pathway?

A

The end product that allows feedback inhibition

86
Q

What is competitive inhibition?

A

When the inhibitor binds to the active site

87
Q

The chemical structure of inhibitor is similar to what?

A

Substrate

88
Q

What happens in non-competitive inhibition?

A

inhibitor binds to a site other than the active site

89
Q

In which non competitive inhibitor is the action reversible?

A

Allosteric inhibitors
Some are not reversible

90
Q

Mercery oxidizes the S-H groups of amino acid cysteine and converts to ______

A

Cystine

  • cystine cannot form important S-S bond, so enzyme changes shape and becomes nonfunctional
91
Q

What do the central metabolic pathways generate?

A

ATP, reducing power NADH, NADPH, precursor metabolites

92
Q

Glucose molecules can be completely oxidized to CO2 which does what?

A

Generates maximum ATP

93
Q

Glucose molecules can bo siphoned off as ________ for use in biosynthesis

How much ATP does it produce?

A

Precursor metabolite

It won’t produce maximum ATP

94
Q

What does glycolysis generate?

A

2 ATP by substrate level phosphorylation
2 NADH
2 H
6 different precursor metabolites

95
Q

What does the pentose Phosphate Cycle generate?

A

NADPH
H
2 different precursor metabolites

96
Q

What does the transition step repeated twice do?

A

oxidizes two molecules of pyruvate to acetyl -CoA

97
Q

What does the transition step generate?

A

2 NADH
2H
1 precursor metabolite

98
Q

What does the TCA cycle, repeated twice do?

A

incorporates two acetyl groups

99
Q

What does the TCA cycle generate?

A

2 ATP by substrate level phosphorylation
6 NADH
6 H
2 FADH2
2 different precursor metabolites

100
Q

Glycolysis converts what to what?

A

1 glucose to 2 pyruvates

net yield: 2 ATP, NADH

101
Q

What happens in the investment phase of glycolysis?

A

2 ATP consumed
2 phosphate groups added
Glucose split to two 3-carbon molecules

102
Q

What happens in the pay-off phase of glycolysis?

A

3-carbon molecules converted to pyruvate
generates 4 ATP, 2 NAD

103
Q

What does the pentose phosphate pathway do?

A

Breaks down glucose?

104
Q

What is pentose phosphate pathway important for?

A

biosynthesis for precursor metabolites

105
Q

What are the precursor metabolites in pentose phosphate pathway?

A

Ribose 5-phosphate
erythrose 4-phosphate

106
Q

What does pentose phosphate pathway generate variable amounts of?

A

NADPH

107
Q

What is the product of pentose phosphate pathway

A

Glyceraldehyde-3-phosphate can enter glycolysis

108
Q

What happens in the transition step ?

A

CO2 is removed from pyruvate

Electrons transfer to NAD ruding it to NADH and H

109
Q

What happens with the 2-carbon acetyl group in the transition step?

A

joins coenzyme A to form Acetyl- CoA
- links previous pathways to TCA cycles

110
Q

What does TCA cycle stand for?

A

Tricarboxylic Acid cycle

111
Q

What does the TCA cycle do?

A

Completes oxidation of glucose

112
Q

What does TCA cycle produce?

A

2 CO2
2 ATP
6 NADH
2FADH2
Precursor metabolites

113
Q

What does oxidative phosphorylation do?

A

Uses reducing power (NADH, FADH2) generated by glycolysis, transition step, TCA cycle to syntehsize ATP

114
Q

What are the two processes in oxidative phosphorylation?

A
  1. Electron transport chain uses reducing power of NADh, FADH2 to generate proton motive force
  2. ATP synthase uses energy of proton motive force to generate ATP
115
Q

Who developed the oxidative phosphorylation process?

A

Peter Mitchell in 1961

116
Q

Peter Mitchell received a Nobel Prize in 1978 for what?

A

Chemiosmotic theory

117
Q

What is the electron transport chain?

A

series of membrane-embedded electrons carrier

118
Q

What does the ETC accept electrons from?

A

NADH, FADH2

119
Q

In ETC, energy released as ______ are passed from one carrier to the next

A

electrons

120
Q

in ETC, energy pumps _______ across membrane

A

Protons

121
Q

What is the membrane that protons are pumped across in prokaryotes?

A

Cytoplasmic membrane

122
Q

What is the membrane that protons are pumped across in prokaryotes?

A

Inner mitochondrial membrane

123
Q

ETC creates an electrochemical gradient called

A

Proton motive force

124
Q

What are quinones

what do they do

A

Lipid-soluble; move freely in membrane

can transfer electrons between complexes

125
Q

What do cytochromes contain?

A

Heme, molecule with iron atom
several types, can be used to distinguish bacteria

126
Q

What are flavorpteins

A

Proteins to which a flavin is attached
FAD, other flavins synthesized from RIBOFLAVIN

127
Q

Mechanism of proton pumps
- some carriers accept only _______
- some carriers accept only _______

A

Hydrogen atoms (proton-electron pairds)
electrons

128
Q

In proton pumps, _______ arrangement in membrane shuttles protons outside of membrane

A

Spatial

129
Q

In a proton pump, when hydrogen carriers ACCEPTS electron from electron carrier, it does what?

A

picks up proton from inside cell

130
Q

In a proton pump, when hydrogen carrier PASSES electrons to electron carrier, it does whata?

A

protons are released to outside of cell

131
Q

What is the net effect in a proton pump?

A

movement of protons across membrane

132
Q

What is the ETC like of prokaryotes/

A

Variation, single species can have several alternate carriers

133
Q

in aerobic respiration in E. coli can use 2 different _______

A

NADH dehydrogenases

134
Q

In aerobic respiration of E. coli, _______ is equivalent to complex I of mitochondria

A

Proton pump

135
Q

In aerobic respiration of E. coli, _______ is equivalent to complex II of mitochondria

A

Succinate dehydrogenase

136
Q

In aerobic respiration of E.Coli, ther is a lack of equivalents for In aerobic respiration of E. coli, _______ is equivalent to complex I of mitochondria

A

Complex III or cytochrome c

137
Q

In aerobic respiration in E.Coli, _______ shuttle electrons directly to functional equivalent of complex IV

A

Quinones

138
Q

which harvests less energy, anaerobic respiration or aerobic respiration in E.Coli?

A

Anaerobic

139
Q

Anaerobic respiration in E. Coli can synthesize terminal _______ that uses NITRATE as terminal electron acceptor

A

oxidoreductase

140
Q

What does terminal oxidoreductase produce?

A

nitrite

141
Q

E.coli converts nitrite to what?

A

less toxic ammonia

142
Q

Selfate reducers use what as terminal electron acceptors?

A

SO24, sulfate

143
Q

What do sulfate reducers produce as end product?

A

Hydrogen sulfide

144
Q

what is the ATP yield of aerobic respiration in prokaryotes for substrate level phosphorylation?

A

2 ATP (from glycolysis; net gain)
2 ATP from TCA cycle

4 ATP TOTAL

145
Q

What is the ATP yield of aerobic respiration in prokaryotes for oxidative phosphorylation?

A

6 ATP from reducing power gained in glycolysis
6 ATP from reducing power gained in transition step
22 ATP from reducing power gained in TCA cycle

34 ATP total

146
Q

What is the total ATP gain in aerobic respiration for prokaryotes?

A

38 ATP

147
Q

When is fermentation used?

A

When respiration is not an option/ when the cell doesn’t have an ETC

148
Q

What type of of bacteria is E. Coli?

A

Facultative anaerobe

149
Q

What does streptoccus pneumoniae lack?

A

ETC

150
Q

What must strep. pneumoniae use for respiration?

A

fermentation

151
Q

ATP generating reactions are only those of _______

A

Glycolysis

152
Q

microbes other than glucose can secrete _______, transport subunits into a cell, degrade into _______

A

Enzymes, precursor metabolites

153
Q

_______ and _______ are broken down by amylases, cellulases, disaccharides

A

Polysaccharides and disaccharides

154
Q

for polysaccharides and disaccharides, _______ enters glycolysis directly, other _______ convert to precursor metabolites

A

glucose, monosaccharides

155
Q

for lipids broken down my lipases, _______ converts to _______ and enters glycolysis

A

Glycerol, dihydroxyacetone phosphate

156
Q

for lipids, fatty acids are degraded by _______ to enter _______ phase

A

B-oxidation, TCA cycle

157
Q

Proteins are broken down by

A

Proteases

158
Q

For proteins, amino group is _______

_______ convert to precursor metabolites

A

Deaminated

carbon skeletons

159
Q

What are chemolithotrophs?

A

Prokaryotes who can use reduced inorganic compounds as energy sources

160
Q

Hydrogen sulfide and ammonia are produced by _______ respiration when _______ molecules serve as terminal electron acceptors

A

Anaerobic respiration, inorganic

161
Q

Hydrogen sulfide and ammonia are used as energy sources for _______ and _______

A

Sulfur bacteria and nitrifying bacteria

162
Q

hydrogen bacteria can also use _______ compounds for energy

A

simple organic

163
Q

Sulfur bacteria can live at a pH of _______

A

less than 1

164
Q

iron bacteria have _______ in their sheaths

A

Iron oxide

165
Q

Nitrifying bacteria are important in the _______ cycle

A

Nitrogen

166
Q

prokaryotes similar in biosynthesis processes synthesize subunits using precursor metabolites formed in _______ pathways

A

central metabolic pathways

167
Q

If enzymes are lacking, end product must be supplies
- _______ bacteria require many growth factors

A

Fastidious

168
Q

Lipid synthesis requires _______ and _______

A

Fatty acids and glycerol

169
Q

What are fatty acids made of?

A

2 carbon units added to acetyl group from acetyl-CoA
- usually 14, 16, 18 carbons

170
Q

What is glycerol synthesized from?

A

Dihydroxyacetone phosphate generated during glycolysis

171
Q

Synthesis of _______ provides mechanism for incorporation of nitrogen into organic material

A

Glutamate

172
Q

what is commonly used via glutamate synthesis?

A

Ammonium

173
Q

_______ can generate other amino acids in amino acid synthesis

A

Transamination

174
Q

Aromatic amino acids: branching pathway
- precursors form _______ compound that enters branching pathway
- amino acids are _______ inhibitors of enzymes that directs branch to its own synthesis
- Amino acids also inhibit formation of _______
- Result is _______

A

7-carbon
feedback
original 7-carbon
cell does not make amino acids that are already present

175
Q

in nucleotide synthesis, DNA, RNA are initially synthesized as _______

A

Ribonucleotides

176
Q

What are purines?

A

Atoms added to ribose 5-phosphate to form ring

177
Q

What are pyrimidines?

A

Ring made than attached to ribose 5-phosphate

Microbiology (16 decks)

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