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Biomed 2 - Season finale > Medical Micro - Bacteriology > Flashcards

Medical Micro - Bacteriology Flashcards

1
Q

what are the 2 types of bacterial cells

A

gram +
gram -

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2
Q

difference between bacteria and archaea

A

lack peptidoglycan in cell walls
mostly studied in extreme environments
have different types of lipids in their membrane

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3
Q

features of crenarchaetoa and where do they reside

A

Thermophilic & hyperthermophilic.
Cool marine planktonic waters

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4
Q

features of euryarchaetoa

A

methanogens
Halophiles
Thermoacidophiles

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5
Q

what do methanogens do

A

use H2 to reduce CO2 to CH4

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6
Q

where do halophiles reside

A

Halophiles – live in very high salt environments

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7
Q

what are optimum conditions for thermacidophiles

A

have an optimum growth temperature between 60 – 80C
live at low pH

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8
Q

what are protozoans

A

protista
eukaryotic cell

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9
Q

where do protozoans inhabit and what do they consume

A

water and soil
feed on bacteria and small particles

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10
Q

how do protozoans reproduce

A

sexually and asexually

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11
Q

how do protozoans consume their food

A

absorb nutrients through their membrane or wrap themselves around their prey to ingest

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12
Q

what is the size range of a protozoan

A

2μm - 2mm

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13
Q

what is a virus

A

Obligate intracellular parasites – cannot replicate by themselves

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14
Q

what kingdom do virus belong to

A

no kingdom

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15
Q

how is information organised within a virus

A

ds DNA, ss DNA, ds RNA, ss RNA – usually organised as single linear or circular molecule of nucleic acid.

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16
Q

structure and function of the caspid

A

protein subunits
protects the nucleic acids

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17
Q

what is marine snow

A

loose association of microbes with organic detritus

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18
Q

what are pellicles

A

predominantly 2D structures forming on surface of liquids

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19
Q

what is step 1and 2 of biofilm formation

A

adhesion
reversible and irreversible

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20
Q

what is step 3 of biofilm formation

A

maturation 1
formation of microcolonies surrounded by EPS

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21
Q

what is step 4 of biofilm maturation

A

maturation 2
formation of a continuous biofilm

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22
Q

what is step 5 of biofilm formation

A

dispersion and sloughing off
due to programmed cell death, lytic phage expression or NO signalling

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23
Q

what is step 6 of biofilm formation

A

transport of biofilm particles
dispersed organisms phenotypically similar to planktonic cells

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24
Q

what is EPS

A

extracellular polymeric substance
house of biofilm

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25
Q

list biopolymers of microbial origins

A

polysaccharides
proteins
glycolipids, phospholipids, LPS
nucleic acids

26
Q

what does bacterial biofilm act as

A

a major barrier to wound healing

27
Q

outline initial reversible adhesion

A

adhesion at a distance of 5-20nm
little energy needed to remove bacteria

28
Q

outline irreversible adhesion

A

binding is mediated by polymer bridging - achieved by reduced radius of body
irreversible binding
specific receptor/adhesion process
achieved by bacteria but not colloids

29
Q

outline the structural function of peptidoglycan

A

forms sheets around the cell - connected by cross links to form a polymer
can be 90% of gram-positive cell wall

30
Q

in gram-negative bacteria what is used as an effective bacteria

A

lipopolysaccharide layer
LPS

31
Q

what is the purpose of understanding the differences of gram-negative/positive cell walls

A

important for targeting bacteria
many antibiotics are effective in targeting gram-positive bacteria but show little specificity for gram-negative bacteria

32
Q

in terms of microbial locomotion what is the purpose of gas vesicles

A

allow regulation of position in water column for some aquatic species

33
Q

what are some forms of bacterial motility except flagella

A

twitching
gliding
swarming

34
Q

what are the 3 main morphologies of dsDNA phages

A

myophage
siphophage
podophage

35
Q

what allows phages to have different specificity

A

absorption apparatus

36
Q

what is rigid body motion

A

rotation of the phage that allows it to inject genetic material into the host

37
Q

what is reversible absorption

A

first contact of the phage with the receptor on the cell surface

38
Q

what is irreversible absorbtion

A

phage walks on the cell surface to find a spot to absorb irreversibly
AKA moon walk

39
Q

how does long flexible ejection system work

A

the phage uses a screw like mechanism that reaches the host cytoplasm

40
Q

how does viral contractile ejection system work

A

the phage docks and ejects genetic material into the host cytoplasm

41
Q

what is the difference between lytic and lysogenic phages

A

lytic - replicates phages and kills cell
temperate - introduces viral genetic material into host genome

42
Q

functions of endolysins/holins step 0

A

lytic protein accumulation

43
Q

step 1 of endolysins/holins function

A

inner membrane disruption

44
Q

step 2 of endolysins/holins function

A

peptidoglycan disruption

45
Q

step 3 of endolysins/holins function

A

outer membrane fusion with inner membrane

46
Q

what is the lysogenic cycle

A

phage inserts its viral genetic material into host genome
does not kill the host - initially

47
Q

how do temperate phages decide between lytic or lysogenic

A

lysogenic - low amount of host compared to phages
lytic - abundance of hosts to infect
phages communicate to each other to decide

48
Q

what is the pseudo-lysogenic cycle

A

phage infects a cell that does not want to divide
phage remains in the cell as a molecule
only one of the daughter cells carries phage DNA

49
Q

step 1 for capsid formation in the cell

A

terminase binds viral genome

50
Q

step 2 of capsid formation in the cell

A

terminase-DNA binds procapsid portal

51
Q

step 3 of capsid formation in the cell

A

DNA translocation

52
Q

step 4 of capsid formation in the cell

A

contamer cleavage and packaging completion

53
Q

what are different antiviral resistance methods

A

preventing virus absorption
preventing virus DNA entry
cutting virus nucleic acids
abortive infections

54
Q

how is virus absorption blocked

A

the host can mutate or mask its receptors
phage cannot undergo irreversible binding

55
Q

how do phages bypass receptor masking by EPS

A

phages produce EPS degrading enzymes

56
Q

what is superinfection exclusion

A

when a virus infects a host cell and commands the cell to not allow other viruses to enter

57
Q

how is superinfection exclusion mechanism achieved

A

expression of:
Imm - redirects DNA outsides
Sp - blocks T4 lysosome

58
Q

how is cutting virus nucleic acids mechanism acheived

A

host DNA is protected from cleavage, viral DNA is not
i.e. methylation

59
Q

how can phages bypass virus nucleic acid cleavage

A

modify nucleotides, makes it bulkier
enzymes cannot reach nucleic acids to cleave it

60
Q

how is the abortive infection mechanism achieved

A

Phage DNA replication is detected by RexA
activated RexA activates RexB
RexB allows escape of +ions
membrane potential is lost and ATP synthesis is blocked

Biomed 2 - Season finale (24 decks)

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