8. Introduction to microbiology Flashcards Preview

EMS - Mechanisms of Disease > 8. Introduction to microbiology > Flashcards

Flashcards in 8. Introduction to microbiology Deck (26):
1

which terms are used to described micro-organisms that cause disease?

virulent or pathogenic

2

what do Koch'e postulates state?

1. the causative organism must be isolated from every individual suffering from the disease
2. the causative organism must be cultivated artificially in pure culture
3. when the causative organism is inoculated from pure culture, the typical symptoms of the infection must result
4. the causative organism must be recoverable from individuals who are infected experimentally

3

what are Koch's postulates for genes?

1. introduction of the gene into a strain that previously did not cause the disease should transform the strain into one that does cause disease
2. gene must be expressed during infection
3. antibodies raised against the gene product or other immunity should protect experimental subjects against disease

4

what constitutes a virus?

nucleic acid core and a protein coat. some viruses may also have an envelope, but some others are naked

5

what is the genetic material in a virus?

either DNA or RNA, but not both

6

what is the protein coat in viruses made of?

capsomeres

7

which viruses attack bacteria?

bacteriophage

8

what are viroids?

infectious naked RNA molecules that infect plants. they are not associated with any proteins

9

what is a prion?

an infectious protein

10

what is the cell wall in microfungi made of?

chitin

11

what are hyphae and mycelia?

hyphae - tiny filaments formed by fungi
mycelia - mats of hyphae

12

what infections do moulds cause?

common, superficial infections eg. ringworm, athlete's foot

13

what is the most common yeast infection, and which species is responsible?

thrush, candida albicans

14

what are the 4 classes of protista?

1. apicomplxa
2. flagellate protista
3. ciliate protista
4. amoebae

15

what is the shape of most bacteria?

round (cocci) or rod shaped (bacilli)

16

what differentiates gram positive bacteria from gram negative bacteria?

gram positive - peptidoglycan in their cell wall
gram negative - very little or no peptidoglycan in their cell wall

17

what allows gram negative substances to adhere to surfaces?

hair like structures called fimbriae

18

which bacteria cannot be killed by phagocytosis?

those which are enclosed in a capsule

19

what is the function of endospores/spores?

protect bacteria against heat, radiation and desication

20

what are the ways in which infections can be spread?

1. airborne
2. faecal-oral route
3. sexually transmissible
4. direct inoculation
5. animal vectors
6. animal reservoirs
7. inanimate vectors (fomites)

21

what does control of infection depend upon?

identifying the mode of spread
interrupting the cycle of infection, replication and spread

22

what does the cycle of infection require to sustain itself?

1. encounter an adhere to a host
2. multiply within that host
3. be dispersed to encounter other hosts

23

examples of intoxication illnesses

tetanus
botulism ergotism

24

what is an intoxication illness?

illness in which the victim does not need to encounter live micro-organisms because disease results from exposure to a toxin rather than a living micro-organism

25

what is the mechanism by which bacteria cause diseases?

1. production of structures that enable the micro-organism to attach to the surface at which they cause disease
2. production of one or more toxins
3. production of aggressins
4. initiating undesirable consequences of the host defences

26

what are the types of toxins?

endotoxins (found in cell wall)
exotoxins (produced by the bacteria)