lesson three

Question 1

prokaryote

Answer 1

• bacteria
• small unicellular organisms
• all proteins begin with a special amino acid, formylmethionine

Question 2

eukaryote

Answer 2

• fungi, plant cells, protozoa, metozoa, human cells
• all proteins begin with the amino acid methionine

Question 3

bacterial motility

Answer 3

flagella, axial filament

Question 4

attachment and conjugation between bacteria

Answer 4

pili/fimbriae
1. attachment to cells/tissues
2. to some extent can pull bacteria along the surface of cells so motility
3. sex pilus (transfer of plasmid)

Question 5

bacterial capsule or glycoclyx

Answer 5

function: evasion from white blood cells

Question 6

peptidoglycan

Answer 6

lattice structure like a mesh

Question 7

lipopolysaccharide

Answer 7

outer membrane, only g-
- lipid a: endotoxin anchors in bacterial outer membrane
- polysaccharide: o antigen projects outward from the cell

Question 8

teichoic and lipoteichoic acids

Answer 8

only gram +
- attached to peptidoglycan layer, project outwards and cause cells to have a negative charge

Question 9

plasma membrane: human vs. fungi cells

Answer 9

• human cell plasma membrane contains cholesterol
• fungi cells plasma membrane contains ergosterol

Question 10

endospores

Answer 10

• resting cells
• genetic material within a
  hard coat
• resistant to heat
• drying
• UV radiation
• chemicals
  (function for bacteria is survival)
• produced by clostridium and bacillus

Question 11

Clostridium difficile

Answer 11

• A major cause of nosocomial infection globally
• Anaerobic Gram + rod that produces endospores

Question 12

What kind of organism is C. difficile?

Answer 12

• Strict anaerobe, Gram-positive bacillus, spore forming
• fecal-oral transmission
  spores are not living
  spores not inactivated by antibiotics, alcohols, or alcohol based hand cleansers

Question 13

Virulence factors and Pathogenicity of C. difficile

Answer 13

• Spores are ingested, not affected by stomach acid and
  germinate in the intestine after contact with bile acids
• Exotoxins made by vegetative bacteria damage intestinal mucosa, kill cells and cause epithelium to leak leading to watery diarrhea

Question 14

C. difficile endotoxins

Answer 14

• TcdA
• TcdB
  CDT- C difficile binary toxin

Question 15

C. difficile syndromes

Answer 15

• dehydration
• diseases are:
  AAD (antibiotic associated diarrhea)
• AAC (antibiotic associated colitis)
• CDAD (Clostridium difficile associated diarrhea)
• PMC (pseudomembranous colitis)
• Toxic megacolon (gangrene of intestines)
• Death

Question 16

children under 2 with C. difficile

Answer 16

never have symptomatic
C. difficile infection but they may harbour the bacterium

Question 17

conventional treatment of C. difficile

Answer 17

antibiotics

Question 18

• nonconventional treatment of C. difficile

Answer 18

• probiotics
• fecal implants

Question 19

bacteria not stained by grams stain

Answer 19

• Mycobacterium sp i.e. M. tuberculosis (causes TB)
  (cell wall has peptidoglycan but large amounts of mycolic acid which prevent stain penetration)
• Mycoplasma sp i.e. M. pneumoniae (causes pneumonia)
  (no cell wall and no peptidoglycan; contains large amounts of sterols)