4. BACTERIAL METABOLISM Flashcards

1
Q

What term describes the biochemical reactions used by bacteria to break down and synthesize compounds?

A

Bacterial metabolism

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2
Q

What is analyzed to determine a microorganism’s carbon source utilization?

A

Substrate utilization

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3
Q

What diagnostic aspect looks at the production of specific substances from substrates?

A

End product production

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4
Q

Diagnostic schemes to analyse each unkwon microorganism

A
  1. Utilization of substrates
  2. Production of End products
  3. pH
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5
Q

What term describes the breakdown of chemical substrates coupled with oxidation-reduction reactions?

A

Energy production

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6
Q

What are the two mechanisms bacteria use to produce energy from carbohydrates?

A

Fermentation and Respiration

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7
Q

What type of process is fermentation?

A

Anaerobic

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8
Q

In fermentation, what type of compound is used as the electron acceptor?

A

Organic compound

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9
Q

What tests are used to identify anaerobic bacteria in fermentation?

A

Voges-Proskauer (VP) and Methyl Red Tests

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10
Q

What term describes the energy-generating process where molecular oxygen is the final electron acceptor?

A

Respiration

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11
Q

How efficient is fermentation in energy generation?

A

Less efficient

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12
Q

What accumulates in the medium as a result of fermentation?

A

Mixture of end products (lactate, butyrate, ethanol, acetoin)

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13
Q

What type of bacteria use respiration for energy production?

A

Obligate aerobes and facultative anaerobes

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14
Q

What can certain anaerobes use as final electron acceptors in anaerobic respiration?

A

Inorganic forms of oxygen (nitrate and sulfate)

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15
Q

What are the three major biochemical pathways bacteria use to break down glucose to pyruvic acid?

A

Embden-Meyerhof-Parnas (EMP) Glycolytic Pathway,

Pentose Phosphate Pathway,

Entner-Doudoroff Pathway

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16
Q

What is the major pathway for converting glucose to pyruvate?

A

Embden-Meyerhof-Parnas (EMP) Glycolytic Pathway

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17
Q

What reducing power is generated by the EMP Glycolytic Pathway?

A

NADH2

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18
Q

What energy molecule is produced by the EMP Glycolytic Pathway?

A

ATP

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19
Q

Is the EMP Glycolytic Pathway aerobic or anaerobic?

A

Anaerobic

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20
Q

Which pathway is an alternative to the EMP pathway and produces ribulose-5-phosphate?

A

Pentose Phosphate (Phosphogluconate) Pathway

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21
Q

What does the Pentose Phosphate Pathway provide for nucleotide synthesis?

A

Pentoses

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22
Q

What reducing power does the Pentose Phosphate Pathway generate?

A

NADPH

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23
Q

Which bacteria use the Pentose Phosphate Pathway and are heterolactic fermenting?

A

Lactobacilli

24
Q

Which bacteria use the Pentose Phosphate Pathway and lack some enzymes required in the EMP pathway?

A

Brucella abortus

25
Q

In the Entner-Doudoroff Pathway, what is converted to pyruvate and glyceraldehyde phosphate?

A

Glucose-6-phosphate

26
Q

How many NADPH molecules are generated per molecule of glucose in the Entner-Doudoroff Pathway?

A

One NADPH

27
Q

What is the ATP requirement for the Entner-Doudoroff Pathway?

A

One ATP

28
Q

Which bacteria use the Entner-Doudoroff Pathway and are aerobic?

A

Pseudomonas,
Alcaligenes,
Enterococcus faecalis

29
Q

What type of bacteria also use the Entner-Doudoroff Pathway due to lacking certain glycolytic enzymes?

A

Other bacteria (lmao yan lang nasa ppt)

30
Q

What is the major end product of alcoholic fermentation?

A

Ethanol

31
Q

Which organisms are known for alcoholic fermentation?

A

Yeasts

32
Q

Anaerobic Utilization of Pyruvic Acid (Fermentation) examples

A

A. Alcoholic Fermentation
B. Homolactic Fermentation
C. Heterolactic Fermentation
D. Propionic Acid Fermentation
E. Mixed Acid Fermentation
F. Butanediol Fermentation
H. Butyric Acid Fermentation

33
Q

What is the end product of homolactic fermentation?

A

Lactic acid

34
Q

Which genera are known for homolactic fermentation?

A

Streptococcus and Lactobacillus

35
Q

What additional products are produced in heterolactic fermentation besides lactic acid?

A

Carbon dioxide, alcohols, formic acid, and acetic acid

36
Q

Which bacteria are examples of heterolactic fermentation?

A

Some lactobacilli

37
Q

What is the major end product of propionic acid fermentation?

A

Propionic acid

38
Q

Which bacteria are known for propionic acid fermentation?

A

Propionibacterium acnes and some anaerobic non-spore-forming, gram-positive bacilli

39
Q

What acids are produced in mixed acid fermentation?

A

Lactic,
acetic,
succinic, and
formic acids

40
Q

What test is based on the production of strong acid in mixed acid fermentation?

A

Methyl red test

41
Q

Which bacteria are known for mixed acid fermentation?

A

Escherichia, Salmonella, Shigella

42
Q

What are the end products of butanediol fermentation?

A

Acetoin (acetyl methyl carbinol) and 2,3-butanediol

43
Q

What test detects acetoin in butanediol fermentation?

A

Voges-Proskauer (VP) test

44
Q

Which bacteria are known for butanediol fermentation?

A

Klebsiella, Enterobacter, Serratia

45
Q

What is the end product of butyric acid fermentation?

A

Butyric acid, along with acetic acid, CO2, and Hydrogen

46
Q

Which bacteria are known for butyric acid fermentation?

A

Clostridium, Fusobacterium, Eubacterium

47
Q

What is the relationship between the VP reaction and the methyl red test?

A

Organisms positive for the VP reaction usually have a negative methyl red test, and vice versa.

48
Q

Energy Utilization

A
  1. Biosynthesis of new cell components
  2. Maintenance of the physical and chemical integrity of the cell
  3. Activity of the locomotor organelles
  4. Transport of solutes across membranes
  5. Heat production
49
Q

What is the most important pathway for the complete oxidation of a substrate under aerobic conditions?

A

Krebs or Tricarboxylic Acid (TCA) cycle

50
Q

In the Krebs cycle, what happens to pyruvate?

A

Pyruvate is oxidized, creating carbon skeletons for biosynthesis and donating electrons to the electron transport chain.

51
Q

What are the results of the Krebs cycle?

A

Production of acid and evolution of carbon dioxide

52
Q

How is fermentation detected in carbohydrate utilization?

A

By acid production and a color change due to a pH indicator in the culture medium

53
Q

What must be absent for accurate testing of the ability to ferment a sugar other than glucose?

A

Glucose

54
Q

What enzyme is responsible for transporting lactose across the cell wall into the bacterial cytoplasm?

A

β-galactoside permease

55
Q

What enzyme breaks the galactoside bond in lactose fermentation, releasing glucose?

A

β-galactosidase

56
Q

Can all organisms that ferment lactose also ferment glucose?

A

Yes