Micro Metabolism Flashcards

1
Q

Bacteria have how much DNA, haploid or diploid?

A

Haploid

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2
Q

What occurs in the lag phase and exponential phase of bacterial cell division? Why is this important?

A

Bacteria are gathering nutrients and multiplying. this is when they are susceptible to abx

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3
Q

How is cell density determined on agar plates?

A

Counts on plates, or turbidity

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4
Q

What are the two major categories of bacteria that are distinguished by their need for metabolites?

A

Anaerobic and aerobic

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5
Q

What does it mean for a bacteria to be a facultative anaerobe?

A

Will usually use oxygen, but is able to survive without it

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6
Q

What is the process that aerobic bacteria use to metabolize energy? What about anaerobic?

A

Aerobic = respiration

Anaerobic = fermentation

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7
Q

What does it mean for a microbe to be microaerophilic?

A

Grows best at low oxygen, but can grow without it as well

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8
Q

What are the enzymes that allow microbes to utilize oxygen without being damaged by oxygen radicals?

A

Superoxide dismutase

Catalase

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9
Q

What is the reaction that catalase catalyze?

A

hydrogen peroxide to water

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10
Q

What is the reaction that super oxide dismutase catalyzes?

A

superoxide to hydrogen peroxide

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11
Q

What is anerobic respiration?

A

Using a chemical other than oxygen as the final electron acceptor in the ETC

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12
Q

How can bacteria be identified by fermentation?

A

The type of product produced

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13
Q

What is folate, and why is it an important target for abx?

A

Nutrient created by bacteria involved in nucleic acid synthesis in bacteria–eukaryotes take this up in their diet, thus this is a target for abx

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14
Q

What is the bacterial enzyme that serves to unwind DNA, and is a target for abx? Which abx is it that targets this?

A

Gyrase, which is targeted by quinolones

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15
Q

Transcription and translation can occur simultaneously in bacteria because there is no nuclear membrane to separate the processes. The bacterial DNA-dependent RNA polymerase is inhibited by [BLANK] (an antibiotic often used in the treatment of tuberculosis).

A

Rifampin

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16
Q

Why is the peptidoglycan layer of the cell wall a good target for abx? (2)

A

Is it both unique and essential

17
Q

What are the five areas of bacterial cells that serve as targets for abx?

A
  1. Cell wall synthesis
  2. DNA replication
  3. RNA synthesis
  4. Protein synthesis
  5. Antimetabolites
18
Q

What causes the decline phase of bacterial growth?

A

build up of waste products of lack of nutrients. Cells stop growing, but are not yet dying

19
Q

What happens in the decline phase of bacterial cells growth?

A

Cells die d/t metabolites

20
Q

What is the target to inhibit protein synthesis replication in bacteria?

A

the 70s ribosome

21
Q

What is different about transcription/translation in prokaryotes vs eukaryotes?

A

Transcription and translation occur simultaneously in prokaryotes

22
Q

How many times more efficient is respiration over fermentation?

A

19x

23
Q

What is the precursor subunit of peptidylglycan?

A

UDP-N acetyl muramic acid (UDP-NAM)

24
Q

Where is UDP-NAM synthesized in the cell?

A

cytoplasm

25
Q

What is the first step in peptidylglycan synthesis?

A

A lactyl group is added to carbon number three of UDP-N-acetyl-glucosamine to form UDP-N-acetyl-muramic acid

26
Q

What is the next step in peptidylglycan synthesis after UDP-NAM is formed?

A

Five amino acids are added sequentially to UDP-NAM to form a pentapeptide side chain.

27
Q

Are there tRNA and ribsomes used in the reaction that adds amino acids to UDP-NAM?

A

No

28
Q

What is the next step in peptidylglycan synthesis after five amino acids are added to UDP-NAM?

A

The NAM pentapeptide is transferred from UDP to bactoprenol phosphate at the membrane surface.

29
Q

What is the protein that is on the internal side of the plasma membrane in eukaryotes, that takes peptidylglycan subunits across the membrane?

A

Bactoprenol

30
Q

What is the third amino acid that is attached to NAM?

A

L-lys or some other diamino acid

31
Q

What is the step in peptidylglycan synthesis after NAM is attached to bactoprenol?

A

NAG is added to the NAM/bactoprenol complex

32
Q

What is the next step in peptidylglycan synthesis after the NAG is added to NAM/bactoprenol complex?

A

The complex is carrier across the membrane

33
Q

What happens to the NAM-NAG-bactoprenol complex after it is transported across the membrane?

A

The dissaccharide unit is attached to the growing end of a peptidylglycan chain by transglycosylases

34
Q

What is the enzyme that attaches the NAM-NAG complex to a developing peptidylglycan molecule?

A

Transglycosylases

35
Q

What is the final step in peptidyl glycan synthesis?

A

Pyrophophobactoprenol is converted back to phosphobactoprenol and recycled

36
Q

Where does transpeptidation occur?

A

between the free amine of the diamino acid in the third position of the pentapeptide and the D-alanine at the 4th position of the other peptide chain

37
Q

What are the drugs that target transpeptidation?

A

Penicillin binding proteins

38
Q

What is transpeptidation?

A

the cross-linking of peptide chains by peptide bond exchange

During peptidoglycan synthesis, this occurs on the outer leaflet of the plasma membrane.

39
Q

What is the mechanism of action of vancomycin?

A

binds to the D-Ala-D-Ala structure to block the transpeptidase reactions