Brainscape's Knowledge GenomeTM

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


See full index

phase 2a > bacteria as causes of diseases > Flashcards

bacteria as causes of diseases Flashcards

1
Q

what is a pathogen?

A

Organism that causes or is capable of causing disease

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

what is a commensal?

A

Organism which colonises the host but causes no disease in normal circumstances

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

what is an opportunist pathogen?

A

Microbe that only causes disease if host defences are compromised

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

what is virulence/ pathogenicity?

A

The degree to which a given organism is pathogenic

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

what is asymptomatic carriage?

A

When a pathogen is carried harmlessly at a tissue site where it causes no disease

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

in bacterial morphology what is the gram stain ?

A

positive- purple ( double cell membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

in bacterial morphology what is the bacteria ?

A

stain pink= negative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are protists?

A

larger microbes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the membrane of gram negative bacteria

A

2 membranes
an inner and outer membrane
separated by lipoprotein, preiplasmic space and peptidogyclan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are the two membranes in gram negative bacteria separated by?

A

separated by lipoprotein, periplasmic space and peptidoglycan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are areas open to bacterial colonisation called?

A

mucosal surfaces

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

what are the two bacterial toxins?

A

endotoxin
exotoxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

describe endotoxin

A

component of the outer membrane of bacteria, e.g. lipopolysaccharide in gram negative bacteria

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

describe the nucleus of bacteria

A

doesn’t have one
naked
dna transcribed in cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

describe exotoxin

A

secreted proteins of gram positive and gram negative bacteria that causes damage to host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what are the two ways there is genetic variation in bacteria?

A

mutation
gene transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

how do mutations increase genetic variation in bacteria?

A

base substitution
deletion
transfer

18
Q

how does gene transfer increase genetic variation in bacteria?

A

Transformation e.g. plasmid
Transduction e.g. via phage
Conjugation e.g. via sex pilus

19
Q

what are the 4 steps of preparing a gram stain?

A
  1. Apply a primary stain such as crystal violet (purple) to heat fixed bacteria
  2. Add iodide which binds to crystal violet and helps fix it to the cell wall
  3. Decolourise with ethanol or acetone
  4. Counterstain with safranin (pink)
20
Q

what is the environment bacteria can survive in?

A

Temperature
<-800C to + 80C (1200C for spores)
pH
<4-9
Water/dessication
2 hours – 3 months (>50 years for spores)
Light
UV

21
Q

what is exotoxin made up of?

A

protein

22
Q

what is endotoxin made up of?

A

lipopolysacccharide

23
Q

what is the action of exotoxin

A

specific

24
Q

what is the action of endotoxin?

A

non- specific

25
Q

what is the effect of heat on exotoxin?

A

labile

26
Q

what is the effect of heat on endotoxin?

A

stable

27
Q

what is the antigenicity of exotoxin?

A

strong

28
Q

what is the antigenicity of endootoxin?

A

weak

29
Q

can exotoxin or endotoxin be converted to toxoid?

A

exotoxin can
endotoxin can’t

30
Q

what does the bacterial chromosome contain?

A

2-4 x 10^3 kb

31
Q

what do plasmids do and contain?

A

transfer promotion genes
contain plasmid maintenance genes
contain antibiotic or virulence dominant genes

32
Q

what does the coagulase test do?

A

Distinguishes S.aureus from other staphylococci – coagulase positive

33
Q

what are the two main groups of classification of bacteria?

A

OBLIGATE
INTRACELLULAR BACTERIA
or
BACTERIA THAT MAY BE CULTURED
ON ARTIFICIAL MEDIA

34
Q

describe obligate intracellular bacteria

A

grow inside cells
can’t culture normally

35
Q

what are the two main categories of bacteria that may be cultured on artificial media?

A

WITH A CELL WALL
or
WITHOUT CELL WALL
( can be remembered using mollicutes)

36
Q

what are the two categories for those with a cell wall?

A

GROWING AS SINGLE CELLS
or
GROWING AS FILAMENTS

37
Q

What does the oxidate test test for?

A

Tests if micro-organism contains a cytochrome oxidase – implies organism able to use oxygen as the terminal electron acceptor

38
Q

what are the three types of haemolysis?

A

alpha
beta
gamma

39
Q

describe alpha haemolysis

A

haemolysis causing by production of hydrogen peroxide oxidising haemoglobin – the agar appears green

40
Q

describe beta haemolysis

A

haemolysis results because of lysis of red blood cells by haemolysis such as Streptolysin O produced by S.pyogenes

41
Q

describe gamma haemolysis

A

haemolysis implies no haemolysis

phase 2a (67 decks)

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