6.2 Bacteria As Pathogens Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is a pathogen

A

A disease chasing microorganism
Can invade and cause harm to host tissues

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

How do pathogens get into the body

A

Must penetrate host interface with environment (interface is a surface or boundary linking two environments)
e.g. lining of digestive system or gas exchange system

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

How does the body prevent entry of pathogens

A

Mucus- thick later and is hard to penetrate
Enzyme- break down the pathogen
Stomach acid- kills microorganism

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

How do bacterial pathogens cause disease

A

1- produce exotoxins
2- produce endotoxin
3- host tissues invasion

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

What is gram staining

A

A strain which differentiates between two types of bacteria based on cell wall structure

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

Gram + bacteria

A

Thick layer of peptidoglycan
Just inner membrane (no outer)
Has teichoic acid and a periplasmic space
Does not produce endotoxins

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

Gam - bacteria

A

Thin layer of peptidoglycan
Outer and inner membrane
More lipopolysaccharide

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

What does gram staining detect

A

Peptidoglycan barrier

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

What is the advantage of the more complex structure of Gram- cell walls

A

Extra protection from the action of antibacterial agents e.g. lysozyme and penicillin

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

How does penicillin kill bacteria

A

Effects formation of cross linkages in cell wall
Wall is weakened so osmotic changes occur
Cell lysis

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

Which bacteria use endotoxin

A

Gram -

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

Which bacteria use exotoxins

A

Gram+ and Gram-

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

What is the relationship of endotoxin and bacteria cell

A

Part of cell surface membrane

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

What is the relationship of exotoxin and bacteria cell

A

Secreted by cell

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

Chemical nature of endotoxin

A

Lipopolysaccharide

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

Chemical nature of exotoxin

A

Polypeptide or protein

17
Q

Which toxin has higher potency

A

Exotoxin

18
Q

Which toxin can be denatured

A

Exotoxin

19
Q

Action of endotoxin

A

Once released, usually from bacterial cell death, causes inflammation and cell death

20
Q

Action of exotoxin

A

Destroy cell membrane or overstimulate the immune system (cytokine storm)

21
Q

Infections associated with endotoxin

A

Salmonella

22
Q

Infections associated with exotoxin

A

Staphylococcus aureus

23
Q

O specific competent of endotoxin

A

Lives outside cell membrane
Needed to infect and invade host

24
Q

Effects of endotoxin

A

Effects are around infection site
Symptoms include fever, vomiting and diarrhoea (bc cells don’t absorb water)
Take a few hours for symptoms

25
Q

Use of antibiotics to treat endotoxins

A

Use bacteriostatic
To recent further cell death and release of endotoxin in cell lysis
Prevents worsening symptoms

26
Q

Is endotoxin denatured in cooking

A

Yes
Because high heat denatures enzymes and kills bacteria

27
Q

Which gram if bacteria produce staphylococcus

A

Positive

28
Q

Are exotoxins soluble

A

Yes so easily transported around the body causing widespread effects

29
Q

How do exotoxins get released and infect

A

Produced and secreted as part of normal growth and metabolism to colonise host
Bind to specific receptors on host cell

30
Q

Antigenic properties of exotoxins

A

Highly antigenic so stimulation production of antitoxins which inactivate them

31
Q

What is an antitoxin

A

Bind and neutralise toxin by preventing receptor binding

32
Q

TB full name

A

Mycobacterium tuberculosis

33
Q

How does mycobacterium tuberculosis cause disease

A

Host tissue invasion

34
Q

What does mycobacterium tuberculosis infect

A

Phagocytes in the lung

35
Q

Why is the first invasion normally symptomless

A

Infected phagocytes are sealed in tubercles as a result of inflammatory response of the lungs

36
Q

What occurs during mycobacterium tuberculosis dormancy period

A

Bacteria not destroyed by immune system bc of thick waxy coat produced protecting them from macrophage enzymes

37
Q

penicillin

A

only effects gram +
because gram + has a thick cell wall
interferes with the formation of cross links
during synthesis of cell walls
so bacteria is susceptible to osmotic shock