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Flashcards in Bacteria (Part I) Deck (117)
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1

what are the three methods of transfer of plasmids?

direct conjugation, infective viral transduction, or transformation

2

Why are plasmids significant?

they confer various factors and traits to bacteria allowing them additional virulence factors or antibiotic resistance

3

What are the 4 steps following heat fixing material to slide?

1) Crystal violet (primary dye) 2) Iodine (dye trapping agent) 3) Alcohol (decolorizer) 4) Safranin (counterstain)

4

Why are gram positive bacteria purple?

they have a relatively thick cross-linked cell wall made up of peptidoglycan which helps to retain the crystal violet stain

5

What is the composition of gram negative cell walls?

they have thinner cell walls with a high lipid content which is primarily washed away by the alcohol

6

What gives gram negative bacteria their pink stain?

the safranin (the counterstain)

7

the gram positive bacteria have a thick peptidoglycan wall with embedded what? (2)

techoic and lipoteichoic acids

8

What is used in serologic bacterial identification? (2)

techoic and lipoteichoic acids

9

What do the lipopolysaccharides on the gram negative bacteria cell wall contain?

lipid A- which can act as an endotoxin

10

What are 2 gram stain exceptions?

gram variable bacteria and acid fast bacilli

11

what are 2 examples of gram variable bacteria?

clostridium and bacillus species

12

What is an example of an acid fast bacilli?

mycobacterium tuberculosis

13

What do acid fast bacilli contain and why is this important?

they contain mycolic acids, which make it difficult for the gram stain to penetrate the waxy cell wall

14

How is the acid fast stain different from the gram stain?

the acid fast stain has a different primary stain and counter stain the the typical gram stain. It also utilizes an acid decolorizer step

15

how are cocci bacteria characterized?

spherical balls

16

how can cocci be arranged? (3)

in pairs called diplococci, chains called streptococci, or clusters called staphylococci

17

Some bacilli have unique features such as what?

the presence of spores or the presence of club shaped ends

18

when a bacteria has an ovoid shape in between a rod and a sphere what is it referred to as?

coccobacillus

19

what are the helical shaped bacteria called?

spirochete

20

what are the curvilinear bacteria referred to as?

spirilla

21

Besides gram stains, what else can be used to see spirochetes and spirilla bacteria?

silver stain

22

what are the comma shaped bacteria?

vibrio

23

What are the pros and cons of molecular techniques for microbiology?

pros: sensitive and specific cons: expensive

24

what is serology utilized for?

organisms that don't culture well (fastidious organisms) and for which there is not a good nucleic acid test developed

25

what is an example of an organism that uses serologic tests for diagnosis?

syphilis- from Treponema pallidum

26

What are the 6 major types of gram positive disease causing bacteria?

1) Staphylococcus 2) Streptococcus/Enterococcus 3) Bacillus 4) Clostridium 5) Corynebacterium 6) Listeria

27

the major gram positive disease causing bacteria consist of two main groups. What are these groups?

Cocci and Bacilli

28

How can the gram positive cocci be further broken down?

based on whether the organisms are catalase + or Catalase -

29

How can the gram positive bacilli be further broken down?

based on whether the organism is spore forming or non spore forming

30

how can the gram positive spore forming bacilli be further broken down?

based on whether the organism can grow in oxygen or whether it is anaerobic