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Flashcards in 11. Gram-positive Bacteria Deck (44)
1

3 genera of low %GC bacteria?

Staphylococcus, streptococcus, lactobacillus

2

3 genera of high %GC bacteria?

Propionibacteria, mycobacterium, streptomyces

3

What are endospores?

Spores that are EXTREMELY heat and chemical resistant; are found in SOME G+ bacteria

4

__________ is a phylum of bacteria that are the source of most antibiotics used in medicine today

Actinobacteria

5

Largest genus of Actinobacteria phylum?

Streptomyces

6

Example of a high %GC G+ bacteria that does NOT contain spores?

Corynebacterium diphtheriae

7

Chracteristic of Corynebacterium diphtheriae infection?

Swollen neck

8

What genus of phylum Actinobacteria forms symbiotic associations with plants? What does it do?

Frankia

Helps plant fix N2 while it makes spores in the plant (aid in its own reproduction

9

2 low %GC genera that are medically important? What nutritional group do they belong to?

Staphylococcus and streptococcus

Chemoorganoheterotrophs

10

What 2 species of staph are part of normal skin flora?

S.aureus and S.epidermis

11

Habitat of Staphylococcus

Skin and mucous membranes of warm blooded animals

12

Shape of staph?

Grape-like cluseters

13

Do Staph/Strept form endospores?

No

14

6 problems cased by S.aureus?

Boils

Abscesses

Impetigo

Food poisoning

Blood infections

Pneumonia

15

What does MRSA stand for?

Methicillin-resistant S.aureus

16

Drug that can treat MRSA?

Vancomycin

17

Habitatof Streptococcus?

Oral cavity and upper respiratory tract

18

3 groups of Streptococci clustered by their phenotype?

Pyogenic, oral, other

19

2 species of pyogenic strep?

S.pyogenes, S.agalactiae

20

2 species of oral strep?

S.mutans, S.gordonii

21

Example of a "other" strep species?

S.thermophilus

22

What does pyogenic mean?

Pus-forming

23

Which streptococci is NON-pathogenic and is thought to be a probiotic?

S. thermophilus

24

How are pyogenic streptococci distinguished?

By their ability to cause a pattern of RBC lysis => beta-hemolysis

25

Which species of streptococci causes strep thoroat/scarlet fever/necrotizing fasiitis?

S.pyogenes

26

Which species of streptococci cause alpha-hemolysis?

S.pneumoniae

27

Which species of strep is part of normal flora in oral cavity and doesn't cause hemolysis?

S.mutans

28

Example of a G+ bacteria genera that produce endospores?

Clostridium

29

What is one way of destroying endospores?

Autoclaving (121degC, 15psi)

30

What triggers endospore formation?

Sporulation when conditions are not optimal (low nutrients, low H2O)

31

Opposite of sporulation?

Germination - production of vegetative cells (regular bacterial cells)

32

2 ways to detect presence of endospores?

Directly - special stains

Indirectly - boil sample for 10 mins, leave at room temp for 24 hrs => if you see germination, had endospores

33

4 ways of describing endospore location?

Central, subterminal, terminal, swollen sporangium

34

What are endospores?

Metabolically dormant form of bacteria

35

How long can endospores last?

~100,000 years

36

Which part of the endospore contains peptidoglycan that will form the wall of the vegetative cell that grows out of the spore?

Core wall

37

Part of endospore that can occupy 1/2 the spore volume?

Cortex

38

Part of endospore that contains many layers of proteins and confers resistance to chemicals?

Spore coat

39

Describe 3 ways the spore components enable the spore to survive extreme conditions?

Spore coat - protects from chemicals/lytic enzymes

Inner membrane - impermeable to many chemicals, including those that cause DNA damage

Core - very low water content. slightly lower pH, dipicolnic acid

40

Why is protein denaturation fine for endospores?

Can re-fold when spore germinates

41

What does dipicolinic acid do? Where is it found?

Complex with calcium ions, inserts into nitrogen bases of DNA to stabilize them

Found in core of endospore

42

Difference in shape between staph and strep?

Staph - grape-like clusters

Strep - pairs/chains of cocci

43

Difference between alpha and beta hemolysis on blood agar?

Alpha - dark green colonies

Beta - media around and under colonies becomes transparent

44

6 things endospores confer resistance to?

Heat, desiccation, UV, gamma-radiation, extreme temps, extreme pH