Bacteriology

Question 1

What color is Gram + ?

Answer 1

Blue

Question 2

What color is Gram - ?

Answer 2

red/pink

Question 3

Gram + characteristics

Answer 3

lack an outer membrane but are surrounded by layers of peptidoglycan many times thicker than is found in the Gram-negatives

thicker and more uniform cell wall
peptidoglycan & teichoic acid
The peptidoglycan desiccates on decourizization (gram stain) making it less permeable to dye complex

Question 4

Gram - characteristics

Answer 4

surrounded by a thin peptidoglycan cell wall

more complex
outer membrane has lippolysaccharides and Porins
Periplasmic space containing smaller amount of peptidoglycan due to its structure, the OM excludes hydrophilic molecules and renders

Question 5

Optimal atmospheric conditions for bacteria

Answer 5

body conditions
pH –> neutral to alkaline
isotonic to hypotonic
temp = 98.6 (but can grow 68-113)

Question 6

(strict or obligate) Aerobes

Answer 6

require O2 for growth (respiratory catabolism)

Question 7

(strict or obligate) Anaerobes

Answer 7

are killed by O2 (fermentative pathways)

Question 8

Facultative Anaerobes

Answer 8

can grow aerobically or anaerobically

Question 9

microaerophiles

Answer 9

require reduced O2 (<the 20% in air)
some also like increased CO2

Question 10

bacterial genome

Answer 10

haploid, circular chromosome
Double stranded DNA

Question 11

Plasmids

Answer 11

Small, circular DNA which can autonomously replicate (either alone or integrated into bacterial genome)

May encode virulence (toxin) and antibiotic resistance genes

Question 12

(Bacterio)Phages

Answer 12

Viruses which infect bacteria
Usually integrate into bacterial genome, but may be independent
May also encode genes