Bacteriology

Question 0

eukaryotic cells characteristics

Answer 0

10-100 micron

• true nucleus and membrane bound organelles
• 80 s ribosomes in mitochondria
• flagella and cytoskeleton
• multiple linear chromosomes
• mitosis and meiosis

Question 1

prokaryotic cells characterics

Answer 1

0. 2-2 micron
   - no nucleus has nucleoid area
   - simple flagella
   - 70s ribosomes
   - single circular ribosomes
   - binary fission replication

Question 2

prion

Answer 2

only present in bacteria

Question 3

bacterial shapes

Answer 3

cocci- spherical
strepo-long chain, diplo ( pairs), entero ( intestine)

bacilli- rod shaped
cocco ( egg shaped)

spiral bacteria ( corkscrew)

• vibrio ( comma)
• spirillum ( spiral, wavy)
• spirochaete ( old telephone, coiled)

Question 4

different types of stains

Answer 4

simple- one color only, white background
differential- gram stain and acid fast
capsule- colors background and bacteria, shows capsule that exclude stain from around organism ( HALO effect)

Question 5

gram stain

Answer 5

based on cell wall structure- amount of peptiologlycan ( mesh/lattice structure)

• useful for antibiotics and tissue damage
• rapid and allows us to see if there is bacteria

Question 6

gram stain procedure

Answer 6

1. fix specimen on slide and flood with methanol or pass slide through a flame
2. Add primary stain- crystal violet ( gentian)
3. Add mordant to keep stain stay in cells-iodine
4. Add acetone-alcohol wash (decolorizer) to wash away purple brown color
   differentiation step: + retain statin and is purple, - lose all stain and is colorless (leaky cell wall)
5. add safranin (counter stain) to allow visibility in microscope
   + doesn’t effect
   - we can see it now!

Question 7

gram negative

Answer 7

thin layer peptidoglycan 
-no teichoic acid
- lipolysaccharide 
-outer membrane and periplasm ( space in inner cell wall)
-less susceptible to penicillin
pink/red

Question 8

gram positive

Answer 8

remains purple

• thick layer peptidoglycan
• teichoic acid present allowing stick to surface charge
• no lipopolysaccharide
• no outer membrane or periplasm
• more susceptible to penicillin

Question 9

Ziehl-Neelsen/acid fast stain

Answer 9

tests for TB
- have wax in cell wall
-carbon fuchsin is added to smear and heated to enhance penetration of dye
-colorization: acid-alcohol removes RED, methytone BLUE colors background
Ex: cryptosporidium- parasite that causes diarrhea

Question 10

glycocalyx

Answer 10

capsule or slime layer ( outer most layer)

Question 11

axial filament

Answer 11

internal flagella in spirochaetes

Question 12

fimbriae and pill

Answer 12

hair-like appendages on gram - bacteria

Question 13

sex pilus

Answer 13

transfer of genes ( DNA from cell to cell)- conjugation

Question 14

peptidoglycan

Answer 14

lattice structure, provides structure for gram +

Question 15

lipopolysaccharide

Answer 15

outer membrane in gram -

• lipid A: endotoxin ( inflammation)
• polysaccharide: O antigen ( typing)

Question 16

teichoic and lipoteichoic acids

Answer 16

attach to peptidoglycan layer, projects outwards and cause cells to have negative charge, easier attachment to host cells and tissues

Question 17

inclusions

Answer 17

reserve deposits of nutrients for bacteria

Question 18

Endospores

Answer 18

genetic material in thick coat, no metabolic activity, resistant to heat and drying chemicals. Clostridium and bacillus produce endospores

Question 19

metabolism

Answer 19

sum total of all chemical reactions within an organism.

• Catabolic: release energy
• Anabolic: produce store energy

Question 20

physical factors for microbial growth

Answer 20

1. temperature: pyschrophiles: cold loving
   - thermophiles: heat loving
   - hyperthermophiles: hot spring
2. pH
   - 5 to 8 for human pathogens
   - acidophiles down, alkalophile up
3. Osmotic pressure
   - obligate halophiles is INCREASE salt
   - falculative halophiles is TOLERATE salt

Question 21

growth requirements for microbacteria

Answer 21

strict aerobe- needs O2
facultative anaerobe- both
Strict anaerobe- minimal O2
Aerotolerant anaerobe- some O2
microaeroble- needs a little of both

Question 22

bacterial growth curve

Answer 22

lag-infection
log- growth of bacteria
stationary-stops growth
death-dies!

Question 23

biofilms

Answer 23

lives in communities like the plaque on our teeth, WBC can’t penetrate, antibiotics are ineffective

Question 24

Agar

Answer 24

complex polysaccharide from algae for culture matrix, add animal blood

Question 25

differential vs. selective media

Answer 25

differential- blood agar, hemolytic reactions ( breakdown of RBC that are mixed with agar) A-partial, B-total, G-none
selective- prevents species from growing and induce others to grow