Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Y1 - Microbio Exam 2 > 2_Bacteriology II > Flashcards

2_Bacteriology II Flashcards

1
Q

bacterial growth phases

A
  1. lag = before cells start to grow – can mimic adaptation to a new body site
  2. log = exponential growth – can mimic rapid or slow growth in the host but results in increased bacterial numbers
  3. stationary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

types of “stationary” phase in the bacterial growth cycle

A
  • stationary
    • survival = balanced slow growth in a subpopulation (no net gain in numbers)
    • death = culture slowly dies out
    • cells in stationary phase can be hypermutable and accumulate mutations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

binary fission:

define

A

growth of bacteria into 2 equal daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

exponential growth typically reflects the…

A

binary fission of bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

doubling time (generation time) of the culture:

define

A

time it takes for the number of cells to increase by a factor of 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what factors slow bacterial growth in a host?

A
  • nutrient availability
  • competition (bacterial cell density)
  • build up of toxic byproducts
  • immune system
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

how do bacteria convert glucose to pyruvate?

A
  • use the Embden-Meyerhof-Parnas pathway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

describe the Embden-Meyerhof-Parnas pathway:

key features

A
  • 2 high energy phosphates are consumed:
    • ATP
    • high energy phosphate PTS system – group translocation
  • 4 ATP are produced.
  • NADH+H+ is produced and must be oxidized by either reduction of pyruvate (fermentation/oxidation) or by being used in an electron transport system (respiration).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In addition to glucose, what are some alternative sugars that can be used by bacteria to produce ATP?

A
  • hexoses
  • complex sugars
  • citrate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are possible endproducts from fermentation?

A
  • acids
    • lactic acid, butyric acid
  • alcohols
    • ethanol, 2,3-butanediol
  • gas
    • CO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what other substrate can bacteria use for respiration?

A

NADH+H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Overview of Respiration in bacteria:

process and outputs

A

Bacteria that respire transform pyruvate –> acetyl-CoA –> break down to CO2.

This provides bacteria with:

  • NADPH for biosynthesis
  • additional molecules of NADH+H+ for use in generating a proton motive force
  • FADH+H+ that can also be used for the generation of a proton motive force
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

proton motive force:

define

A

produced by passing the electrons from NADH+H+ to a series of electron carriers that use the excess energy to pump protons (H+) outside the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

carriers of the proton motive force

A
  • cytochromes
  • quinones
  • flavoproteins (Fe-S proteins)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

final electron acceptor(s) of the proton motive force

A
  • acceptor can be O2 (aerobic respiration, oxidative phosphorylation) or
  • other inorganic compounds (anaerobic respiration).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how does proton motive force generate ATP?

A
  • This creates a membrane potential and a pH gradient.
  • The re-internalization of the protons through F0/F1 ATPase ATP synthase is used to:
    • produce ATP
    • transport small molecules/ions
    • power flagella for motility
17
Q

how do bacteria that use fermentation only differ?

A

can run the ATPase pump backwards, using ATP to pump protons out of the cell and charge the membrane.

18
Q

what are the physical requirements for bacterial growth?

A
  • pH – most pathogens are neutrophiles or acidophiles
  • salt concentration – most pathogens are non-halophillic or halotolerant
  • temperature – most pathogens are mesophils although cold-tolerant bacteria and psychophiles are important in food spoilage
19
Q

define the following growth requirements:

  1. anaerobe
  2. strict anaerobe
  3. aerotolerant anaerobe
A
  1. anaerobe = grows without O2
  2. strict anaerobe = killed by O2
  3. aerotolerant anaerobe = withstands O2
20
Q

define the following growth requirements:

  1. microaerophilic
  2. aerobe
  3. obligate aerobe
  4. facultative
A
  1. microaerophillic prefers reduced O2 tension for growth
  2. aerobe = growths only with oxygen
  3. obligate aerobe only uses O2 as a terminal electron acceptor, must have oxygen
  4. facultative = can grow with or without O2
21
Q

define the following growth media classifications:

  1. complex
  2. defined
  3. enriched
  4. differential
  5. selective
A
  1. complex - numerous non-chemically defined nutrient sources (e.g. yeast)
  2. defined - all components are present in known amounts
  3. enriched - has components to help bacterial growth (i.e. blood)
  4. differential - allows differentiation of bacteria
  5. selective - allows growth of only certain bacteria
22
Q

can a single growth medium have only one growth classification, or can it have multiple?

A

A single medium can have multiple characteristics (e.g. differential and selective).

23
Q

fastidious bacteria:

define

A
  • have specific growth/nutritional requirements.
  • For this reason, a vast majority of the microbiota normal flora has not yet been cultured in the laboratory.
24
Q

describe the selective and differential components of:

MacConkey’s agar

A
  • selective - bile salts, crystal violet (accumulates in the cell to inhibit most Gram-positive bacteria), lactose
  • differential - lactose as a C+E source and neutral red to detect acid production (red)
25
Q

what does hemolysis allow for?

A

Fe-scavenging

(iron scavenging)

26
Q

what test is used to determine if bacteria produce hemolysins?

A

blood agar plates (BAP)

27
Q

what are the 3 types of hemolysis reactions, and define each?

A
  1. gamma-hemolysis (non hemolytic) = no detectable lysis
  2. alpha-hemolysis = partial lysis of RBCs surrounding the bacterial colony indicated by a green zone around the colony
  3. beta-hemolysis = complete lysis of RBCs surrounding the bacterial colony
28
Q

can hemolysis be specific or non-specific?

A

both

e.g. can lyse mammalian cells from multiple species, or can be species specific

29
Q

siderophores:

define and function

A
  • small, high-affinity iron-chelating compounds secreted by bactera; amongst strongest soluble Fe3+ binding agents
  • Fxn:
    • serving to transport iron across cell membranes
    • allow bacteria to scavenge iron from human proteins and from other bacteria

Y1 - Microbio Exam 2 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions