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37 Cards in this Set
- Front
- Back
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1. Why do bacteria break down substrate?
What do diagnostic tests for bacterial metabolism look at? |
1. Produce energy
2. Use simple compounds for biosynthesis to produce macromolecules Look at energy source and how bacteria uses the energy |
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2. How do bacteria convert glucose to pyruvate?
How is the glucose transported into the cell first? What important intermediate is formed and how? How many high energy phosphates are consumes? |
Embden-Meyerhof-Parnas pathway
Group translocation brings sugar in via glycosylation **PTS phosphotransferase system takes sugar up and into cell Additional phosphorylation to form fructose-1,6-diP Two: -ATP -PTS system (group translocation) |
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3. How many ATP are produced in converting glucose to pyruvate?
What else is produced? What must happen to this? |
4 ATP are produced
NADH+ and H+ are produced Must be oxidized by either.... 1. Reduction of pyruvate (fermentation/oxidation) 2. Used in e- transport system (respiration) |
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4. Besides glucose, what other sugars can bacteria convert to fructose-1,6-diP?
What are many of the intermediates in the glucose to pyruvate pathway used for? If pentoses or citrate are used what can gluconeogenesis produce? |
1. Hexoses
2. Complex sugars 3. Citrate Intermediates are used for biosynthesis (anabolism) as well as energy source Can produce glycolytic intermediates |
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5. Why does fermentation of pyruvate occur?
What is the hallmark of fermentation? What are three possible end products that can be produced from the fermentation of sugars? |
B/c bacteria need to reduce pyruvate to recycle NADH+/H+
Production of acid 1. Acids 2. Alcohols 3. Gas |
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6. How do bacteria deal w/ the production of acid from fermentation?
Four ways.... |
1. Neutral products
**formed by the neutralization of acid end-products 2. Stop growing 3. Alternate acid and alcohol production 4. Acid tolerant |
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7. What is produced by homolactic fermentation?
What is produced by heterolactic fermentation? What is produced by mixed acid fermentation? What is produced by clostridial spp. fermentation? |
Lactic acid
Lactic acid, ethanol, CO2, H+ Ethanol, 2,3-butanediol, succinate, lactate, acetate, formate, H2, CO2 ***2,3-butanediol is neutral (unique to mixed acid) Butyric acid, butyl alcohol, acetone, ethanol, H2, CO2 |
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8. What determines if a bacteria can metabolize sugar?
If a bacteria can metabolize sugar, what are the three different types of growth that can be seen? What does the citrate test look for? |
Bacteria can grow w/ a sugar as a carbon source
1. Pellicle 2. Pellet 3. Turbid *grows throughout as individual cells Looks for the use of citrate as sole carbon source |
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9. How is the production of acids by fermentation/oxidation tested?
What happens if the test is positive? |
Tested by adding a pH indicator to the growth medium
Bacteria grows and produces acid causing the pH indicator to change |
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10. How is gas formation scored?
What three questions have bee addressed so far? |
Scored by trapping of gas bubbles in a Durham tube or in the presence of bubbles in the wells of an API strip
1. Can it grow? 2. Is it fermenting? 3. If fermenting, does it produce gas? |
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11. What does the Voges Proskauer test determine?
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If bacteria produces the neutral end products acetoin or 2,3-butandiol
**tell you if you have a mixed acid and enteric |
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12. How is β-galactose formed?
What is required to use β-galactose for further metabolism? What does the ONPG assay measure? What does a positive result mean? |
Formed from the breakdown of lactose during lactose metabolism
Requires β-galactosidase Measures β-galactosidase activity Positive means bacteria can convert lactose to β-galactose |
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13. What can some bacteria use NADH+/H+?
What do bacteria that respire do with pyruvate? |
Can use NADH+/H+ for respiration
Transform pyruvate into acetyl-CoA and further break it down to CO2 **run pyruvate through TCA cycle to get more NADH+ |
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14. What does transforming pyruvate to acetyl-CoA provide the bacteria with?
Three things... |
1. NADPH for biosynthesis
2. Additional molecules of NADH+/H+ for use in generating a proton motive force 3. FADH+/H+ that can also be used for the generation of a proton motive force |
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15. Do bacteria have to use oxygen as the final electron acceptor in the electron transport chain?
What other type of respiration can they have? What do they use? |
No, don't have to solely have aerobic respiration
Can have anaerobic respiration Nitrate or thiosulfate can be used a s final electron acceptor |
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16. What three things is the proton motive force used for?
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1. Iron transport
2. Rotate flagella 3. Synthesis of ATP |
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17. What does the oxidase test determine?
What does the hydrogen sulfide production test determine? What does the nitrogen reductase test determine? |
Does the bacteria have cytochromes
Can thiosulfate be used as the final electron acceptors (anaerobic respiration) Can nitrate be the final electron receptor |
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18. Is bacteria growth w/o acid production respiration, fermentation, or both?
Can fermentation occur in the presence of oxygen? What do bacteria that cannot get enough energy from fermentation alone do? |
Respiration only
Fermentation can occur in the presence or absence of oxygen Have both aerobic respiration (oxidation) and fermentation (oxidation positive) in order to grow |
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19. What can the Fe-S proteins used for respiration produce when reacted with oxygen?
How do bacteria neutralize H2O2? What does this neutralization form? |
Produce superoxides and hydrogen peroxides
Neutralize hydrogen peroxide w/ catalases **protect self from free radicals Neutralization forms oxygen |
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20. What does the catalase test do?
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Scores bacteria on the ability to produce bubbles of oxygen in the presence of hydrogen peroxide
**just b/c a bacteria is catalase positive doesn't mean it necessarily respires |
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21. How do bacteria assimilate nitrogen?
What four sources for can bacteria use for NH3? |
Through α-ketoglutarate and glutamate
1. Arginine (from environment) 2. Urea 3. Tryptophan (from environment) 4. Anaerobic respiration and nitrate reductase **nitrogen fixation doesn't play a major source |
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22. What does the urease test determine?
What does the indole test determine? What does the arginine dehydrogenase test (ADH) determine? |
Determines if urea can be used as an NH3 source
**ammonia is produced from urea so pH goes up & phenol red turns pink Determines if tryptophan can be used as a NH3 source **break down tryptophan to indole and NH3 If arginine can be used as a source for NH3 |
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23. What tests can be used to determine where bacteria get ammonia from?
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1. Urease test
(source: urea) 2. Indole test (source: tryptophan) 3. Arginine dehydrogenase test (source: arginine) |
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24. What does bacteria use proteases that they produce for?
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Use proteases to degrade proteins to supplement metabolism
**make proteins into free AA |
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25. What can the free AA from degraded proteins be used for?
Three things... |
1. Used in biosynthesis
2. Converted to AA precursors 3. Converted to pyruvate for use in the TCA cycle for energy and biosynthesis |
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26. What two things does the hydrogen sulfide production test determine?
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Determines whether hydrogen sulfide (H2S) is produced from either:
1. Use of thiosulfate as terminal e- acceptor in repsiration 2. Produced from breakdown of cysteine (AA) |
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27. What does the lysine decarboxylase test (LDC) determine?
What does the ornithin decarboxylase test (ODC) determine? |
Whether lysine can be broken down into cadaverine
**cadaverine is used to make a bunch of different amino acids Determines whether ornithine can be converted to putrescine **putrescine is also an AA precursor |
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28. What test look at a bacteria's ability to scavenge amino acids?
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1. Hydrogen sulfide test
2. Lysine decarboxylase test (LDC) 3. Ornithine decarboxylase test (ODC) |
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29. What do bacteria use for iron (Fe) scavenging?
What is the origin of these? How do bacteria directly scavenge iron? |
Siderophores (Fe-chelating protein)
**siderophores strip iron from human source Either human or bacterial origin Direct uptake where they take iron containing molecules from the source and break them down to get iron |
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30. How are RBC's related to iron scavenging?
What are blood agar plates (BAP) used to determine? |
Lysis of RBC's allows for Fe-scavenging
Determine if bacteria produce hemolysins |
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31. What are the three hemolysis reactions that are possible?
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1. γ-hemolysis - no detectable lysis
2. α-hemolysis - partial lysis of RBCs 3. β-hemolysis - complete lysis of RBCs |
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32. How is α-hemolysis identified?
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Partial lysis of RBC surrounding bacterial colony is indicated by a green zone around the colony
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33. What do phospholiapses do?
What can these products then be converted to? |
Liberate pyruvate and FA
They can be converted to acetyl-CoA and feed into the TCA cycle |
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34. What does the addition of Tween 10 to blood agar plates do?
Two things.... |
1. Solubilize phospholipids
2. Increase growth of bacteria that can metabolize host phospholipids |
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35. What are one carbon transfers using tetrahydrofolic acid (TFA) essential to?
Can bacteria transport folate? |
Synthesis of...
-DNA -RNA -methionine containing proteins Bacteria cannot transport folate **can't take folate acid up |
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36. What do bacteria synthesize TFA from?
(two things) What are sulfonamides and what do they do? |
1. PABA
2. Pteridine PABA analog that inhibit the TFA biosynthetic pathway |
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37. What is trimethoprim?
What does it bind to? What does it thus do? |
Antibiotic
Binds to dihydrofolate reductase Inhibits TFA biosynthetic pathway |
