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MICR221 > L3 Two sides of bacterial endospores > Flashcards

L3 Two sides of bacterial endospores Flashcards

1
Q

What are the two main genus names tend to form endospores

A

bacillus

clostridium

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2
Q

what type of bacteria form endospores (not genus)

A

gram positive rods

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3
Q

how long does it take for a cell to make an endospore?

A

8 hours

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4
Q

when do cells produce endospores

A

when the cell is subject to significant stress

as a last resort effort

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5
Q

what are the three options for a cell when it is subjected to significant stress

A

die
enter dormancy
form endospores

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6
Q

once conditions are optimal how long does it take for an endospore to germinate

A

15 minutes

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7
Q

steps of endospore creation

A

the vegetative cell begins to divide by binary fission
DNA becomes denser and septum forms asymmetrically
larger compartment (mother cell) engulfs the smaller compartment (forespore)
the peptidoglycan enclosing the forespore forms the cortex
the mother cell makes proteins that forms the coat
the mother cell degrades (lysis)

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8
Q

what are the 7 layers of the endospore

A 
core
inner membrane
germ cell wall 
cortex 
outer membrane 
coat
exosporium
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9
Q

what does the actual core contain

A

metabolically inactive DNA and ribosomes

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10
Q

what three layers are in the core group of endospores

A

core
inner membrane
germ cell wall

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11
Q

what does the second functional group of the endospore contain

A

cortex

outer membrane

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12
Q

what is the cortex made up of

A

less crosslinked peptidoglycan

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13
Q

what is the 3rd functional layer of the endospores

A

coat

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14
Q

what is the coat and purpose

A

surrounds the cortex
composed of many protein layers
can be very thick and is impermeable (chemical and UV resistance)

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15
Q

what is the 4th functional layer of an endospore

A

exosporium

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16
Q

what is an exosporium and purpose

A

thin outer layer
lipid carbohydrate and protein
overall coat to the endospore

17
Q

what 2 attributes groups determines endospore resistance

A

physical

chemical

18
Q

what physical factors contribute to endospore resistance

A 
coat (thick layers)
inner membrane (impermable)
19
Q

what chemical factors determine endospore resistance

A 
CORE
low water content
lower pH
high content of dipicolinic acid and Ca2+
small acid-soluble proteins

CORTEX
decreased peptidoglycan cross-linking (2.9%)

20
Q

what is the water content of an endospore

A

15%

21
Q

how does a high conc of dipicolinic acid and Ca2+ contribute to resistance

A

the Ca2+ link to the dipiclonic acid and DNA forming lattice structure

22
Q

what do small acid-soluble proteins do?

A

these bind to DNA and alter the conformation of DNA which protects it from damage

23
Q

how does having a lower peptidoglycan cross-linking in the cortex help resistance?

A

required for spore coat dehydration, metabolic dormancy and heat resistance

24
Q

compare the peptidoglycan of vegetative cells with endospores

A

33% in vege

2.9% in endo

25
Q

what are the three phases of endospore germination

A

activation
germination
outgrowth

26
Q

what does activation involve

A

preparing the endospore for germination

27
Q

what does the germination phase involve

A

endospore swells up, rupturing the spore coat

loss of resistance, modified peptidoglycan is involved

28
Q

what does outgrowth involve

A

spore emerges from remains of coat and develops into vegetative cells

29
Q

microbe of the day

A

bacillus subtilis

30
Q

bacillus subtilis type, niche, use in sterilisation

A

gram-positive rod
naturally found in soil and the gut of ruminants and humans
can survive very stressful environments
used to indicate efficacy of sterilisation

31
Q

definition of the results of physical control methods

A 
death
sterilisation
disinfection
antisepsis
bactericidal (kill)
bacteriostatic (inhibits)
32
Q

two types of heat as a physical control method

A

moist heat

dry heat

33
Q

types of moist heat

A

autoclave
boiling water
pasteurisation

34
Q

what temperature, time must an autoclave meet

A

121 degrees

15 minutes

35
Q

what temperature does bioling water get to

A

100 degrees

so does not kill endospores

36
Q

two types of pasteurisation

A

batch

flash

37
Q

what does batch pasteurisation involve

A

low temp long time

63 degrees 30 mins

38
Q

what does flash pasteurisation involve

A

high temp short time
71 degrees
15 seconds

39
Q

two types of dry heat

A

flaming/ incineration

hot air oven

MICR221 (23 decks)

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