11. Gram-positive Bacteria Flashcards Preview

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

3 genera of low %GC bacteria?

A

Staphylococcus, streptococcus, lactobacillus

2
Q

3 genera of high %GC bacteria?

A

Propionibacteria, mycobacterium, streptomyces

3
Q

What are endospores?

A

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

4
Q

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

A

Actinobacteria

5
Q

Largest genus of Actinobacteria phylum?

A

Streptomyces

6
Q

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

A

Corynebacterium diphtheriae

7
Q

Chracteristic of Corynebacterium diphtheriae infection?

A

Swollen neck

8
Q

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

A

Frankia

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

9
Q

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

A

Staphylococcus and streptococcus

Chemoorganoheterotrophs

10
Q

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

A

S.aureus and S.epidermis

11
Q

Habitat of Staphylococcus

A

Skin and mucous membranes of warm blooded animals

12
Q

Shape of staph?

A

Grape-like cluseters

13
Q

Do Staph/Strept form endospores?

A

No

14
Q

6 problems cased by S.aureus?

A

Boils

Abscesses

Impetigo

Food poisoning

Blood infections

Pneumonia

15
Q

What does MRSA stand for?

A

Methicillin-resistant S.aureus

16
Q

Drug that can treat MRSA?

A

Vancomycin

17
Q

Habitatof Streptococcus?

A

Oral cavity and upper respiratory tract

18
Q

3 groups of Streptococci clustered by their phenotype?

A

Pyogenic, oral, other

19
Q

2 species of pyogenic strep?

A

S.pyogenes, S.agalactiae

20
Q

2 species of oral strep?

A

S.mutans, S.gordonii

21
Q

Example of a “other” strep species?

A

S.thermophilus

22
Q

What does pyogenic mean?

A

Pus-forming

23
Q

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

A

S. thermophilus

24
Q

How are pyogenic streptococci distinguished?

A

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

25
Q

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

A

S.pyogenes

26
Q

Which species of streptococci cause alpha-hemolysis?

A

S.pneumoniae

27
Q

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

A

S.mutans

28
Q

Example of a G+ bacteria genera that produce endospores?

A

Clostridium

29
Q

What is one way of destroying endospores?

A

Autoclaving (121degC, 15psi)

30
Q

What triggers endospore formation?

A

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

31
Q

Opposite of sporulation?

A

Germination - production of vegetative cells (regular bacterial cells)

32
Q

2 ways to detect presence of endospores?

A

Directly - special stains

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

33
Q

4 ways of describing endospore location?

A

Central, subterminal, terminal, swollen sporangium

34
Q

What are endospores?

A

Metabolically dormant form of bacteria

35
Q

How long can endospores last?

A

~100,000 years

36
Q

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

A

Core wall

37
Q

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

A

Cortex

38
Q

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

A

Spore coat

39
Q

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

A

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
Q

Why is protein denaturation fine for endospores?

A

Can re-fold when spore germinates

41
Q

What does dipicolinic acid do? Where is it found?

A

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

Found in core of endospore

42
Q

Difference in shape between staph and strep?

A

Staph - grape-like clusters

Strep - pairs/chains of cocci

43
Q

Difference between alpha and beta hemolysis on blood agar?

A

Alpha - dark green colonies

Beta - media around and under colonies becomes transparent

44
Q

6 things endospores confer resistance to?

A

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