Ch 2

Question 1

endospore

Answer 1

• found in bacillus and clostridium
• SURVIVAL (and transmission) not reproductive (1 bacterium/vegetative cell –> 1 spore) (spores of fungi have reproductive role)
• resistance to chemicals, dessiccation, radiation, freezing and heat
• Structure: core: DNA, ribosomes, glycolytic enzymes –> cytoplasmic membrane –> spore wall (normal PG) –> cortex (thick layer of less cross-linked PG) –> keratin spore coat (protein)

Question 2

In which stage of bacterial growth are antibiotics/chemo most effective?

Answer 2

• the log phase: logarithmic or exponential growth

Question 3

Bacterial growth curve

Answer 3

1. lag phase: at the beginning = when the bacteria are adjusting to their new environment. They aren’t replicating, but they’re getting READY to = # of cells at beginning of lag phase = # of cells at end of lag phase.
2. log phase: logarithmic or exponential growth
3. stationary phase: nutrients used up; toxic products like acids and alkali begin to accumulate; # of new cells = # of dying cells (levels off)
4. death phase

Question 4

obligate aerobes

Answer 4

• require O2
• have no fermentative pathways
• generally produce superoxide dismutase
• important ex) mycobacterium; pseudomonas; (bacillus)
• ex) “non-fermenting gram - rod” = pseudomonas

Question 5

microaerophilic

Answer 5

• require low but not full O2 tension

- ex) campylobacter, helicobacter (both curved, gram - rods from the GI)

Question 6

facultative anaerobes

Answer 6

• will respire aerobically until O2 is depleted and then ferment
• most bacteria ex) enterobacteriaceae

Question 7

obligate anaerobes

Answer 7

• lack superoxide dismutase
• generally lack catalase
• are fermenters
• can’t use O2 as terminal e- acceptor
• ABC: Actinomyces, Bacteroides, Clostridium
• “didn’t grow in presence of O2”
• Anaerobic infections STINK!

Question 8

Steps of a Gram Stain

Answer 8

1. crystal violet (a very intense purple, small dye molecule)
   - stains gram + purple/blue
   - stains gram - purple/blue
2. gram’s iodine
   - stains gram+ purple/blue (a large dye complex)
   - stains gram- purple/blue (a large dye complex)
3. acetone or alcohol
   - stains gram + purple/blue
   - stains gram - colorless
4. safranin (a pale dye)
   - stains gram + purple/blue
   - stains gram - red/pink
   * background in stain modified for tissues will be pale red*

Question 9

all spore formers are ____

Answer 9

all spore formers are gram +

Question 10

Niehl-Neelsen Acid Fast Stain (or kinyoun)
Reagent: carbol fuchsin w/ heat
* without the heat, the dye would not go into the mycobacterial cells

Answer 10

Acid Fast: red (hot pink)

non-acid-fast: red (hot pink)

Question 11

Niehl-Neelsen Acid Fast Stain (or kinyoun)

Reagent: acid alcohol

Answer 11

Acid Fast: red

non-acid-fast: colorless

Question 12

Niehl-Neelsen Acid Fast Stain (or kinyoun)
Reagent: methylene blue
* sputa and human cells will be blue

Answer 12

Acid Fast: red

non-acid-fast: blue

Question 13

all cocci are _____ except _____

Answer 13

all cocci are gram + except Neisseria, Moraxella, veillonella

Question 14

Acid Stains:
mycobacterium is ___
nocardia is ____

Answer 14

• mycobacterium is acid fast (will stain red; i.e. pink rods)
• nocardia is partially acid fast

Question 15

• two protozoan parasites have acid fast oocysts

Answer 15

• cryptosporidium and isospora

- two protozoan parasites (cryptosporidium and isospora have acid fast oocysts

Question 16

Gram + Rods

Answer 16

Major League Baseball Catchers Never Catch Anyone

• M: mycobacterium (acid fast) facultative intracellular
• L: listeria: facultative intracellular; exotoxin
• B: bacillus: spore former, exotoxin
• C: clostridium: spore former, exotoxin
• N: nocardia (branching/filamentous; weakly acid fast)
• C: corynebacterium: exotoxin
• A: actinomyces (branching/filamentous)

Question 17

Gram - Cocci

Answer 17

• neisseria

- moraxella

Question 18

Gram + Cocci

Answer 18

Staph and Strep