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Flashcards in Micro 2- Diagnostic Micro Deck (31):
1

what is a plasmid?

self-replicating circular pieces of DNA
-often code for proteins that enhance the pathogenicity of a bacterium

2

conjugative plasmid

carries genes for sex pili and transfer of the plasmid

3

dissimilation plasmids

encode enzymes for the catabolism of unusual compounds

4

resistance factors (R factors)

encode antibiotic resistance

5

what are transposons?

segments of DNA that can move one region of DNA to another

6

transposons contain

insertion sequences (IS) that code for transposes that cuts and reseals DNA

7

what is special about complex transposons

they carry other genes (e.g. in antibiotic resistance)

8

what are morphological characteristics?

useful for identifying eukaryotes, tell little about phylogenic relationships

9

what is differential staining used for?

gram staining, acid-fast staining, not useful for bacteria without cell walls

10

what can biochemical tests identify about microorganisms?

determine presence of bacterial enzymes

11

a fermentation test shows

bacteria that catabolize carbohydrate or potion produce acid, causing the pH indicator to change color

12

oxidase tests for

identifies bacteria that have cytochrome oxidase (e.g. Neisseria gonorrhoeae, pseudomonas)

13

what are rapid identification methods?

perform several biochemical tests simultaneously
-results of each test are assigned a number

14

what is serology

the science that studies serum and immune responses in serum

15

what does "microorganisms are antigenic" mean?

they stimulate the body to form antibodies

16

antiserum-

a solution of antibodies is tested against an unknown bacterium

17

what occurs in a slide agglutination test

bacteria agglutinate when mixed with antiserum-containing antibodies produced in response to that species/strain

18

enzyme linked immunosorbent assay (ELISA)

known antibodies and an unknown type of bacterium are added to a well
-a reaction identifies the bacteria

19

western blotting

identifies antibodies in a patient's serum, confirms HIV infection

20

what is phage typing?

test for determining which phages a bacterium is susceptible to

21

procedure of phage typing

-stain in question is grown over entire plate
-a drop of different phage type is placed on bacteria
-clearning called plaques appear where phages infect and lyse bacterial cells

22

example of how phage typing can be used- specific genus/family

used to distinguish S. enterica serotypes and S. aureus types

23

nucleic acid analysis via DNA base composition tests for

-percentage of guanine + cytosine
-two organisms that are closely related have similar amounts of various bases

24

nucleic acid analysis via DNA fingerprint tests for

-electrophoresis of restriction enzymes digests an organism's DNA
-comparing fragments from different organisms provides information on genetic similarities and differences

25

how do nucleic acid amplification tests work

use of PCR to amplify DNA of an unknown microorganism that cannot be cultured

26

how does nucleic acid hybridization work

measures the ability of DNA strands from one organism to hybridize with DNA strands of another organism
(greater degree of hybridization, greater degree of relatedness)

27

southern blotting uses

uses nucleic acid hybridization to identify unknown microorganisms using DNA probes

28

what does a DNA chip (microarray) contain, and what is its function

contains DNA probes and detects pathogens by hybridization between the probe and DNA in the sample

29

two types of DNA chip (microarray)

-ribotyping
-fluorescent in situ hybridization (FISH)

30

ribotyping

rRNA sequencing
(type of DNA chip-microarray)

31

fluroescent in situ hybridization (FISH)

fluroescent DNA or RNA probes stain the microorganisms being targeted