Bacterial Growth and Division: L3A Flashcards

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1
Q

define growth

A

result of cell division and key to the life of a bacterium

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2
Q

binary fission

A

elongation of cell to twice original length, formation of partition that constricts cell into two daughter cells

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3
Q

generation time

A

time for one cell to generate to two cells

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4
Q

budding division:

A

formation of new daughter cell with mother cell retaining its identity

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5
Q

One generation of growth

A
  1. Macromolecules e.g proteins accumulate in cytoplasm
  2. Incorporated into cell wall, membrane, ribosomes enzymes and new DNA
  3. DNA replicates
  4. Cell elongates
  5. Semi-conservative, newly made DNA separates into two chromosomes
  6. Chromosomes move to opposite poles
  7. Septum forms in middle of elongated cell and it separates into two
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6
Q

Bacterial cell division stages?

A

stage 1: chromosome replication

stage 2: chromosome segregation

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7
Q

what is a divisome?

A

complex of cell proteins controlling the division

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8
Q

what do min proteins control?

A

FtsZ

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9
Q

what does bactoprenol transport when making new peptidoglycan?

A

new precursors across cytoplasmic membrane

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10
Q

what do autolysins do when making new peptidoglycan?

A

make gaps in the cell wall

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11
Q

what does bactoprenol interact with?

A

transglycosylases to insert precursors into cell wall

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12
Q

what is transpeptidation

A

Final step in peptidoglycan synthesis

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13
Q

what inhibits the transpeptidase

A

Penicillin

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14
Q

how does bacteria grow?

A

exponentially

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15
Q

name the stages of bacteria growth (graph)

A

LAG - adaptation

LOG - (exponential) cells dividing rapidly

STATIONARY - nutrients depletes, division = death rate

DEATH - waste metabolites build up, cells die

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16
Q

how do we use microscopy for microbial growth?

A

total cell count

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17
Q

how do we use colony counting for microbial growth?

A

viable bacterial numbers

18
Q

what are the 3 method for bacterial growth?

A

spread plate, pour plate, micropipetting

19
Q

what does spectrophotometry measure?

A

optical density

20
Q

what are psychrophiles?

A

they grow at log temperatures (0-20)

21
Q

what grows at midrange temperatures?

A

Mesophiles (20-40)

22
Q

what are thermophiles?

A

grow at high temps +45

23
Q

what grows at VERY high temperatures?

A

hypthermophiles - above 80

24
Q

what do acidophilus have?

A

very stable cytoplasmic membranes destroyed at neutral pH

25
Q

what do cytoplasmic membranes restrict?

A

proton entry

26
Q

what do alkaliphiles have?

A

unique energy requirements and are killed at too low a pH

27
Q

what pH must the internal environment be for bacteria

A

the same pH for all bacteria usually pH 4-9

28
Q

what are halophiles?

A

Grown in high SALT concentrations, 6-15% NaCl

29
Q

what are halotolerant?

A

Grow in high salt concentrations but prefer none, 1-6% NaCl

30
Q

what are extreme halophiles?

A

Grow in very high salt concentrations - 15-30% NaCl

31
Q

what are osmophiles?

A

grow in high SUGAR concentrations

32
Q

what are xerophiles?

A

grow in dry environment

33
Q

what are aerobes full of?

A

full of oxygen tension

34
Q

what do microaerophiles use?

A

oxygen when it is present at a lower concentration than air

35
Q

what do facultative aerobe grow without?

A

oxygen in the correct environment

36
Q

what are anaerobes?

A

cannot respire oxygen

37
Q

what are aerotolerant anaerobes?

A

can tolerate oxygen

38
Q

what is an obligate anaerobe?

A

killed by oxygen

39
Q

what is sporulation?

A

Survival tactic of some bacteria

40
Q

describe facts about sporulation

A
  • Metabolically inactive so dont need nutrients
  • Highly resistant to heat, chemicals etc
  • Spread by wins, animals, water, through the gut
41
Q

what are factors of sporulation?

A
  • Stress leads to the phosphorylation of sporulation factors
42
Q

why are spores medically important?

A
  • Major cause of hospital acquired diarrhoea
  • Hard to eradicate
  • Transmission and outbreaks hard to control