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Metabolism II Flashcards

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1
Q

Pentose phosphate pathway: used to break down what molecule

A

Glucose

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2
Q

Pentose phosphate pathway: first reaction

A

Glucose-6-phosphate to ribulose-5-phosphate (pentose sugar)

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3
Q

Pentose phosphate pathway generates many _____ for ____.

A

Sugars

Biosynthesis

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4
Q

Net yield of pentose phosphate pathway

A

6 NADPH (reducing power for biosynthesis), 1 ATP

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5
Q

Entner-Doudoroff pathway: used to break down what molecule

A

Glucose

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6
Q

Entner-Doudoroff pathway combines reactions of what 2 pathways?

A

Glycolysis and pentose phosphate

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7
Q

Net yield of Entner-Doudoroff pathway

A

1 ATP, 1 NADH, 1 NADPH

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8
Q

What electron carrying molecule is found in pentose phosphate and Entner-Doudoroff pathways but not in glycolysis?

A

NADPH

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9
Q

Tricarboxylic acid cycle: ____ is completely oxidized to ____

A

Pyruvate

CO2

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10
Q

Where does tricarboxylic acid cycle take place in eukaryotes? Where in prokaryotes?

A

Eukaryotes: mitochondria
Prokaryotes: cytoplasm

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11
Q

What 3 things does tricarboxylic acid cycle produce?

A

CO2
NADH and FADH2 (another diffusible electron carrier)
Precursors for biosynthesis

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12
Q

Part 1 of tricarboxylic acid cycle

A

Pyruvate oxidized to CO2 and acetyl CoA

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13
Q

Acetyl CoA has what type of high energy bond?

A

Thioester

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14
Q

Part 2 of tricarboxylic acid cycle

A

Acetyl CoA is condensed with oxaloacetate to form citrate

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15
Q

Part 3 of tricarboxylic acid cycle

A

Oxidation and decarboxylation reactions form NADH and CO2 (6 and 5 carbon stages)

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16
Q

Part 4 of tricarboxylic acid cycle

A

Succinyl-CoA to succinate generates high energy GTP (guanosine triphosphate) via substrate level phosphorylation

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17
Q

Part 5 of tricarboxylic acid cycle

A

More oxidations form NADH and FADH2

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18
Q

How many ATP molecules are synthesized directly from oxidation of glucose? When is most ATP made?

A

4 ATP molecules generated from oxidation of glucose

Most ATP made when NADH and FADH are oxidized in electron transport chain

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19
Q

Electrons from _____ and _____ generated by the oxidation of organic substrates during _____ and _____ are transferred through a series of _______ to a final terminal ______

A
  1. NADH
  2. FADH
  3. Glycolysis
  4. Tricarboxylic acid cycle
  5. Membrane bound electron carriers
  6. Electron acceptor
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20
Q

Electrons flow from carriers with more _____ E0 to more ____ E0

A

Negative

Positive

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21
Q

How many ATP can be generated per NADH using O2 as terminal electron acceptor?

A

3

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22
Q

Electron transport chains: locations in eukaryotes and in prokaryotes

A

Eukaryotes: mitochondrial membrane
Prokaryotes: plasma membrane

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23
Q

Electron carriers used in electron transport chain

A

Cytochromes and quinones

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24
Q

Chemiosmotic hypothesis

A

Energy released during electron transport is used to establish proton gradient and charge difference across membrane (proton motive force)

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25
Electron flow causes _____ to move outward across the membrane, _____ is made when they move back in
Protons | ATP
26
ATP synthase
Enzyme that uses proton movement to catalyze ATP synthesis
27
Movement of what establishes proton motive force?
Protons
28
What are the two portions of ATP synthase, and where are they located?
F0 portion is embedded in plasma membrane | F1 portion is located in cytoplasm
29
2 subunits of F0 subunit: names, locations, what they do
``` a subunit (left of c subunits) is the proton channel Ring of c subunits (directly above F1 subunit) rotates ```
30
2 portions of F1 subunit: names, locations, what they do
``` Gamma shaft (attaches F1 to c subunits of F0) rotates Rotation of gamma shaft causes conformational changes in alpha and beta subunits (located below gamma shaft) ```
31
Bacteria that can transfer electrons extracellularly onto certain metals
Shewanella
32
Extracellular electron transport: how it works
Electron pass through carriers out of cell through cell layers to iron or other metal
33
Can extracellular electron transport result in synthesis of ATP?
Yes, but electrons wind up outside of cell
34
What a microbial fuel cell is used for
Extracellular electrons are captured to generate electricity
35
Two portions of microbial fuel cell
Anode | Cathode
36
In anode of microbial fuel cell, microbes are fed what that cause them to undergo what two metabolic processes?
Microbes are fed glucose and undergo glycolysis and tricarboxylic acid cycle
37
What is present in the anode that microbes attach to? What is its purpose?
Metal electrode is present for microbes to transfer electrons onto
38
Is the anode oxic or anoxic? Why does this matter?
Anode is anoxic: microbes are forced to attach electrons to electrode rather than oxygen
39
What do the microbes build in the fuel cell?
Biofilm
40
How is the cathode connected to the anode?
Electric wire attached to metal electrode in anode
41
How are electrons pulled into the cathode? What do electrons form in cathode?
Presence of oxygen pulls electrons into cathode | Electrons form water with oxygen
42
Mudwatts
Microbial fuel cells that harness the electrogenic potential of soil microbes to produce electrical power
43
Fermentation: organic or inorganic electron donor, what type of electron acceptor
Organic electron donor | Endogenous organic electron acceptor (ex- pyruvate)
44
Aerobic respiration: organic or inorganic electron donor, what type of electron acceptor?
Organic electron donor | O2 as electron acceptor
45
Anaerobic respiration: organic or inorganic electron donor, what type of electron acceptor?
Organic electron donor | NO3-, SO4-2, CO2, fumarate
46
Chemolithotrophy: organic or inorganic electron donor, what type of electron acceptor?
Inorganic electron donor | O2, SO4-2, NO3-
47
Why does anaerobic respiration generate less ATP than aerobic respiration?
Electron receptors used in anaerobic respiration such as NO3- have less positive reduction potentials as O2 Energy yield is directly related to magnitude of reduction potential difference
48
Denitrification: example of what type of respiration?
Anaerobic respiration
49
Denitrification: what molecule is used as terminal electron acceptor? What is this molecule reduced to?
``` Nitrate (NO3-) Nitrogen gas (N2) ```
50
Example of microbe that uses denitrification: what term is used to describe its relationship with oxygen? Where does it live?
Paracoccus denitrificans Facultative anaerobe Lives in soil
51
What does Paracoccus denitrificans do to the soil? What effect does this have on plants?
Depletes soil nitrogen | Lowers crop yield
52
Commonly studied bacteria that uses denitrification: name, what it does to nitrate and what that reaction forms, term used to describe its relationship with oxygen
Escherichia coli Facultative anaerobe Nitrate is first reduced to nitrite
53
Nitrite strip test
Test for E. coli, as it reduces nitrate to nitrite | Used for diagnosis of urinary tract infections
54
Fermentation: completion of catabolism without what two things?
Electron transport system | Terminal electron acceptor
55
Fermentation occurs where?
Cytoplasm
56
Fermentation: hydrogens from what are transfered onto what?
NADH | Pyruvate
57
Yield of fermentation: 3 things
Fermentation products (lactic acid, ethanol) NAD+ ATP by substrate level phosphorylation
58
Reduction of _____ in _____ is balanced by its oxidation in ______
NAD Glycolysis Fermentation
59
Microbial fermentation plays an important role in what industry? What 4 things are produced by fermentation?
Food industry | Yogurt, cheese, chocolate, alcoholic beverages
60
Major fermentations used in food processing
Lactic Propionic Ethanolic
61
Starter culture for yogurt: what two genuses of bacteria?
Lactobacillus | Streptococcus
62
Yogurt production: _____ is hydrolyzed to _____ which is fermented to _____
Lactose (in milk) Glucose Lactic acid
63
Contamination with what microbe is a major concern in yogurt production?
Bacteriophage
64
Starter culture for cheese: what bacteria and what enzyme? What does the enzyme do?
Lactococcus Enzyme: renin Renin promotes coagulation
65
During ripening stage of cheese production, what is added?
More microbes
66
Starting material, intermediate material, and end product for cheese formation
Milk -> curd -> cheese
67
What type of bacteria is added to make Swiss cheese? What type of fermentation does it undergo?
Propionibacterium undergoes propionic fermentation
68
What type of microbe is added to make bleu and brie cheese? What is its name?
Penicillium (fungus)
69
What type of microbe is used for ethanol fermentation in making wine and beer? What is its name?
Saccharomyces (yeast)
70
Ingredients for wine
Grape juice, sugar, Saccharomyces
71
Ingredients for beer
Barley, hops, water, Saccharomyces
72
What breaks down complex starches and proteins in beer production?
Plant enzymes
73
Ginger beer: ingredients
Ginger spice, sugar, Saccharomyces, Lactobacillus
74
Kombucha tea: what types of microbes used in its production?
Saccharomyces (yeast), Bacillus (bacteria)
75
What is the term used for starter culture of kombucha tea? What does it stand for?
SCOBY: symbiotic colony of bacteria and yeast
76
Using fermentation to differentiate Staphylococcus aureus from Staphylococcus epidermidis
Both strains of Staphylococcus are grown on a mannitol salt agar plate Color change is noted: Staphylococcus aureus ferments mannitol, but Staphylococcus epidermidis does not
77
Chemolithotrophs: what are they, how do they acquire electrons
Microbes that acquire electrons from the oxidation of inorganic sources such as H2, NO2, or Fe+2
78
2 examples of chemolithotrophy
Iron-oxidizing bacteria | Nitrifying bacteria
79
Iron-oxidizing bacteria species
Acidithiobacillus ferrooxidans
80
Iron-oxidizing bacteria oxidize ____ compounds as ____ source using _____ as final ____ ____
1. Iron 2. Electron 3. O2 4. Electron acceptor
81
Iron oxidation generates insoluble _____. What is the impact of this compound on aquatic life?
Ferric hydroxide | Compound is toxic to aquatic life
82
Why does iron oxidation yield little energy?
Iron is not a great electron donor (E0 is too positive)
83
Nitrification: definition
Oxidation of ammonia to nitrate
84
What are the 2 genera of bacteria that work together in nitrification? What reaction does each carry out?
Nitrosomonas (ammonia to nitrite) | Nitrobacter (nitrite to nitrate)
85
Nitrification is used to remove ammonia in what two water sources?
Wastewater and fish tanks
86
Nitrification is often followed by _____.
Denitrification

Microbiology (24 decks)

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