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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
what are two other names for the TCA cycle?
- citric acid cycle - Kreb's cycle
26
what are two important functions of the TCA cycle?
generating energy and it is a source of carbon skeletons used in biosynthesis
27
what kind of bond is the bond between Coenzyme-A and sulfur in acetyl-CoA?
a high energy bond
28
how much of the following does one molecule of glucose generate in the TCA cycle: CO2, NADH, FADH2, GTP (ATP)
- 6 CO2 - 8 NADH - 2 FADH2 - 2 GTP (ATP)
29
how much of the following does one molecule of acetyl-CoA generate in the TCA cycle: CO2, NADH, FADH2, GTP (ATP)
- 2 CO2 - 3 NADH - 1 FADH2 - 1 GTP (ATP)
30
what is the mitochondrial electron transport chain?
a series of e- carriers operating together to transfer e- from NADH to FADH2, to a terminal e- acceptor, O2 (in aerobic respiration)
31
electrons flow from carriers with more negative _____ to carriers with more positive ____
Eo (reduction potential)
32
are protons transported in or out of the cell during NADH oxidation?
out of the cell
33
how do protons re-enter the cell and make ATP?
through ATP synthase and ATP is made through oxidative phosphorylation using the proton motive force
34
how do bacterial and archaeal ETC's differ from mitochondrial ones?
- different electron carriers - may be shorter - may be branched - may have lower phosphate/oxygen ratio (less H+ transported out of the cell)
35
what kind of pathway is the ETC in E. coli?
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
what can proton motive force produced from the ETC be sued for?
- oxidative phosphorylation - flagellar rotation - secondary active transport
37
what are the two portions of ATP synthase?
- F0 (plasma membrane portion) - F1 (cytoplasmic portion)
38
what is a phosphate/oxygen (P/O) ratio?
the number of ATP generated per oxygen
39
what is the P/O of NADH? FADH2? which is more energetically favorable?
- NADH: 2.5 (more favorable) - FADH2: 1.5
40
what is the maximum yield of ATP during aerobic respiration? why doesn't the actual number always reflect this?
- 32 ATP - there are factors affecting max yield
41
what are the four factors that affect ATP yield?
- 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
why does anaerobic respiration usually produce less energy than aerobic?
the final electron acceptor has a more negative/less positive Eo than O2
43
what is the final electron acceptor for enteric bacteria that use anaerobic respiration?
NO3- (nitrate)
44
what is denitrification? is it bad?
- 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
is oxygen needed for fermentation?
nope
46
does fermentation have an ETC? how is ATP generated?
- no, so it has no PMF - ATP is generated by substrate -level phosphorylation
47
what is often the final electron acceptor in fermentation?
pyruvate or a pyruvate derivative
48
how do monosaccharides enter the glycolytic pathway?
they are converted to other sugars that can enter
49
how do di- and polysaccharides enter the glycolytic pathway?
they are cleaved by hydrolases or phosphorylases
50
triglycerides are converted to ___________ and _______ ______ by lipases to be used as energy sources
glycerol and fatty acids. - glycerol is degraded by the glycolytic pathway - fatty acids are often oxidized via the beta-oxidation pathway
51
proteins can be used as a _________ source
carbon
52
what enzyme hydrolyzes protein to amino acids?
protease
53
what is deamination?
removal of an amino group from an amino acid

Microbio 3220 (24 decks)

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