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Microbio 3220 > Exam 2 - Lecture 10 > Flashcards

Exam 2 - Lecture 10 Flashcards

1
Q

what are the three major metabolic requirements for all organisms?

A
  • energy (ATP)
  • electrons (NADH)
  • carbon
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2
Q

what are the six classifications of organisms based on their nutritional requirements?

A
  • phototroph (light energy)
  • chemotroph (chemical energy)
  • lithotroph (inorganic e-)
  • organotroph (organic e-)
  • autotroph (CO2 carbon)
  • heterotroph (organic carbon)
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3
Q

what are the five major nutritional types/classes?

A
  • photolithoautotrophs* (plants)
  • photoorganoheterotrophs
  • chemolithoautotrophs*
  • chemolithoheterotrophs
  • chemoorganoheterotrophs* (higher order animals; pathogens)

*majority of microbes known are in these three categories

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4
Q

what are precursor metabolites?

A

carbon molecules used in biosynthesis

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5
Q

what three processes do chemoorganoheterotrophs use to break down organic molecules?

A
  • aerobic respiration
  • anaerobic respiration
  • fermentation
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6
Q

how is ATP made in respiration?

A

primarily by oxidative phosphorylation

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7
Q

what kind of final electron acceptor is used in anaerobic respiration?

A
  • not oxygen
  • NO3-, SO4, CO2, Fe3+, etc.
  • organic acceptors can be used too
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8
Q

true or false: fermentation only uses an electron transport chain, but no proton motive force.

A

false; it uses neither.

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9
Q

how is ATP made in fermentation?

A

substrate-level phosphorylation

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10
Q

which is more efficient: respiration or fermentation?

A

respiration

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11
Q

what kind of electron acceptor is used in fermentation?

A

an endogenous e- acceptor

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12
Q

what do you call enzymes that work in both catabolic and anabolic directions?

A

amphibolic enzymes

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13
Q

what are four important amphibolic pathways?

A
  • Embden-Meyerhof pathway
  • Entner-Duodoroff pathway
  • pentose phosphate pathway (PPP)
  • TCA (tricarboxylic acid) cycle
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14
Q

what is aerobic respiration?

A

a process that can completely catabolize an organic energy source to CO2 using

  • glycolysis
  • TCA cycle
  • ETC

it also produces ATP and high energy electron carriers like NADH

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15
Q

what are the three common pathways used in aerobic respiration to get from glucose to pyruvate?

A
  • Embden-Meyerhof pathway (most common; plants, animals, microbes)
  • Entner-Duodoroff pathway (used by gram neg soil bacteria and very few gram pos)
  • pentose phosphate pathway (PPP)
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16
Q

what are the two phases of the Embden-Meyerhof pathway?

A
  • six carbon phase
  • three carbon phase
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17
Q

how many ATP does the six carbon phase of the EMP use?

A

2 ATP

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18
Q

how many ATP and NADH does the three carbon phase of the EMP produce? how is the ATP synthesized?

A
  • 4 ATP, 2 NADH
  • substrate-level phosphorylation
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19
Q

what is the net gain of ATP and NADH in the EMP?

A

2 ATP and 2 NADH

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20
Q

what does the Entner-Duodoroff pathway replace? what is the net gain?

A
  • replaces the first step in the EMP
  • net gain: 1 ATP, 1 NADH, 1 NADPH
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21
Q

the Entner-Duodoroff pathway generates less energy that others. bacteria that use it normally don’t need much energy anyway.

A

don’t think this is SOS, just wanted this to be a card.

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22
Q

what is the pentose phosphate pathway also known as?

A

the hexose monophosphate pathway

23
Q

what are the three functions of the PPP?

A
  • produce NADPH
  • sugar transformation reactions
  • produces precursor molecules needed for biosynthesis
24
Q

what are two important metabolites produced from the PPP and what are some of their products?

A
  • erythrose 4-phosphate (aromatic amino acids, Vit B6)
  • ribuose 5-phosphate (nucleic acids)
25
Q

what are two other names for the TCA cycle?

A
  • citric acid cycle
  • Kreb’s cycle
26
Q

what are two important functions of the TCA cycle?

A

generating energy and it is a source of carbon skeletons used in biosynthesis

27
Q

what kind of bond is the bond between Coenzyme-A and sulfur in acetyl-CoA?

A

a high energy bond

28
Q

how much of the following does one molecule of glucose generate in the TCA cycle:

CO2, NADH, FADH2, GTP (ATP)

A
  • 6 CO2
  • 8 NADH
  • 2 FADH2
  • 2 GTP (ATP)
29
Q

how much of the following does one molecule of acetyl-CoA generate in the TCA cycle:

CO2, NADH, FADH2, GTP (ATP)

A
  • 2 CO2
  • 3 NADH
  • 1 FADH2
  • 1 GTP (ATP)
30
Q

what is the mitochondrial electron transport chain?

A

a series of e- carriers operating together to transfer e- from NADH to FADH2, to a terminal e- acceptor, O2 (in aerobic respiration)

31
Q

electrons flow from carriers with more negative _____ to carriers with more positive ____

A

Eo (reduction potential)

32
Q

are protons transported in or out of the cell during NADH oxidation?

A

out of the cell

33
Q

how do protons re-enter the cell and make ATP?

A

through ATP synthase and ATP is made through oxidative phosphorylation using the proton motive force

34
Q

how do bacterial and archaeal ETC’s differ from mitochondrial ones?

A
  • different electron carriers
  • may be shorter
  • may be branched
  • may have lower phosphate/oxygen ratio (less H+ transported out of the cell)
35
Q

what kind of pathway is the ETC in E. coli?

A

branched pathway
- upper branch: stationary phase and low aeration conditions (less efficient, less H+ transported)
- lower branch: log phase and high aeration conditions (more efficient)

36
Q

what can proton motive force produced from the ETC be sued for?

A
  • oxidative phosphorylation
  • flagellar rotation
  • secondary active transport
37
Q

what are the two portions of ATP synthase?

A
  • F0 (plasma membrane portion)
  • F1 (cytoplasmic portion)
38
Q

what is a phosphate/oxygen (P/O) ratio?

A

the number of ATP generated per oxygen

39
Q

what is the P/O of NADH? FADH2? which is more energetically favorable?

A
  • NADH: 2.5 (more favorable)
  • FADH2: 1.5
40
Q

what is the maximum yield of ATP during aerobic respiration? why doesn’t the actual number always reflect this?

A
  • 32 ATP
  • there are factors affecting max yield
41
Q

what are the four factors that affect ATP yield?

A
  • bacterial ETCs are shorter and have lower P/O ratios
  • ATP production may vary w environmental factors
  • PMF in bacteria and archaea is used for other things besides ATP production
  • precursor metabolites may be used for biosynthesis
42
Q

why does anaerobic respiration usually produce less energy than aerobic?

A

the final electron acceptor has a more negative/less positive Eo than O2

43
Q

what is the final electron acceptor for enteric bacteria that use anaerobic respiration?

A

NO3- (nitrate)

44
Q

what is denitrification? is it bad?

A
  • it’s when nitrogen gas is released outside of the cell
  • yeah, it causes loss of soil fertility, but we also need the release of them a little bit
45
Q

is oxygen needed for fermentation?

A

nope

46
Q

does fermentation have an ETC? how is ATP generated?

A
  • no, so it has no PMF
  • ATP is generated by substrate -level phosphorylation
47
Q

what is often the final electron acceptor in fermentation?

A

pyruvate or a pyruvate derivative

48
Q

how do monosaccharides enter the glycolytic pathway?

A

they are converted to other sugars that can enter

49
Q

how do di- and polysaccharides enter the glycolytic pathway?

A

they are cleaved by hydrolases or phosphorylases

50
Q

triglycerides are converted to ___________ and _______ ______ by lipases to be used as energy sources

A

glycerol and fatty acids.
- glycerol is degraded by the glycolytic pathway
- fatty acids are often oxidized via the beta-oxidation pathway

51
Q

proteins can be used as a _________ source

A

carbon

52
Q

what enzyme hydrolyzes protein to amino acids?

A

protease

53
Q

what is deamination?

A

removal of an amino group from an amino acid

Microbio 3220 (24 decks)

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