11. Gram-positive Bacteria

Question 1

3 genera of low %GC bacteria?

Answer 1

Staphylococcus, streptococcus, lactobacillus

Question 2

3 genera of high %GC bacteria?

Answer 2

Propionibacteria, mycobacterium, streptomyces

Question 3

What are endospores?

Answer 3

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

Question 4

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

Answer 4

Actinobacteria

Question 5

Largest genus of Actinobacteria phylum?

Answer 5

Streptomyces

Question 6

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

Answer 6

Corynebacterium diphtheriae

Question 7

Chracteristic of Corynebacterium diphtheriae infection?

Answer 7

Swollen neck

Question 8

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

Answer 8

Frankia

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

Question 9

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

Answer 9

Staphylococcus and streptococcus

Chemoorganoheterotrophs

Question 10

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

Answer 10

S.aureus and S.epidermis

Question 11

Habitat of Staphylococcus

Answer 11

Skin and mucous membranes of warm blooded animals

Question 12

Shape of staph?

Answer 12

Grape-like cluseters

Question 13

Do Staph/Strept form endospores?

Answer 13

No

Question 14

6 problems cased by S.aureus?

Answer 14

Boils

Abscesses

Impetigo

Food poisoning

Blood infections

Pneumonia

Question 15

What does MRSA stand for?

Answer 15

Methicillin-resistant S.aureus

Question 16

Drug that can treat MRSA?

Answer 16

Vancomycin

Question 17

Habitatof Streptococcus?

Answer 17

Oral cavity and upper respiratory tract

Question 18

3 groups of Streptococci clustered by their phenotype?

Answer 18

Pyogenic, oral, other

Question 19

2 species of pyogenic strep?

Answer 19

S.pyogenes, S.agalactiae

Question 20

2 species of oral strep?

Answer 20

S.mutans, S.gordonii

Question 21

Example of a “other” strep species?

Answer 21

S.thermophilus

Question 22

What does pyogenic mean?

Answer 22

Pus-forming

Question 23

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

Answer 23

S. thermophilus

Question 24

How are pyogenic streptococci distinguished?

Answer 24

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

Question 25

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

Answer 25

S.pyogenes

Question 26

Which species of streptococci cause alpha-hemolysis?

Answer 26

S.pneumoniae

Question 27

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

Answer 27

S.mutans

Question 28

Example of a G+ bacteria genera that produce endospores?

Answer 28

Clostridium

Question 29

What is one way of destroying endospores?

Answer 29

Autoclaving (121degC, 15psi)

Question 30

What triggers endospore formation?

Answer 30

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

Question 31

Opposite of sporulation?

Answer 31

Germination - production of vegetative cells (regular bacterial cells)

Question 32

2 ways to detect presence of endospores?

Answer 32

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

Question 33

4 ways of describing endospore location?

Answer 33

Central, subterminal, terminal, swollen sporangium

Question 34

What are endospores?

Answer 34

Metabolically dormant form of bacteria

Question 35

How long can endospores last?

Answer 35

~100,000 years

Question 36

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

Answer 36

Core wall

Question 37

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

Answer 37

Cortex

Question 38

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

Answer 38

Spore coat

Question 39

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

Answer 39

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

Question 40

Why is protein denaturation fine for endospores?

Answer 40

Can re-fold when spore germinates

Question 41

What does dipicolinic acid do? Where is it found?

Answer 41

Complex with calcium ions, inserts into nitrogen bases of DNA to stabilize them Found in core of endospore

Question 42

Difference in shape between staph and strep?

Answer 42

Staph - grape-like clusters Strep - pairs/chains of cocci

Question 43

Difference between alpha and beta hemolysis on blood agar?

Answer 43

Alpha - dark green colonies Beta - media around and under colonies becomes transparent

Question 44

6 things endospores confer resistance to?

Answer 44

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