Topic 1 Taxonomy: Prokaryotes

Question 1

• Do not have membrane-bound nuclei or organelles

- Eubacteria and Archaea

Answer 1

Prokaryotes

Question 2

• Classified based on shape
  a. Coccus: spherical
  b. Spirochete: spiral
  c. Bacillus: rod

Answer 2

Bacteria

Question 3

• Gram positive
• Gram negative
• Both covered by capsule (virulence factor protecting bacteria from drying out)

Answer 3

Eubacteria

Question 4

• Thick peptidoglycan layer in cell wall
• Stain dark purple
• No outer membrane
• Minor periplasm (outside plasma membrane)
• No lipopolysaccharide (LPS: endotoxin released when bacteria is destroyed)
• Secrete exotoxins
• Contain teichoic acids (polysaccharide connecting peptidoglycan layer and plasma membrane for rigidity and structure)

Answer 4

Gram Positive Bacteria

Question 5

• Thin peptidoglycan in second outer membrane
• Stain pink
• Contains periplasm between inner and outer membranes
• Outer membrane present
• LPS present (in outer membrane)
• Secrete exotoxins
• No teichoic acids

Answer 5

Gram Negative Bacteria

Question 6

• Cell walls
• 70 S ribosomes
• DNA organized in circular plasmids (horizontal gene transfer via pili)
• Flagellum for movement
• Reproduce via binary fission

Answer 6

Similarities between Eubacteria and Archaea

Question 7

• Eubacteria
  a. Cell wall contains peptidoglycan; lipids bound via ester-linkage
  b. Ribosome has unique structure
  c. DNA lacks introns and histones
• Archaea
  a. Cell wall lacks peptidoglycan; lipids bound vis ether-linkage
  b. Ribosome has unique structure
  c. Contain introns, some have histones

Answer 7

Differences between Eubacteria and Archaea