3. Microbiology 101 part 2

Question 1

What are the two cell types

Answer 1

• prokaryotic
• eukaryotic

Question 2

Main difference between prokaryotes and eukaryotes

Answer 2

prokaryotes = no nucleus
eukaryotes = nucleus

Question 3

Key properties of prokaryotes (3)

Answer 3

• Small size (1-2 um)
  ○ High surface / volume ratio
  ○ Favours chemistry
• Rigid cell wall
  ○ Requires transport
  ○ Extracellular enzymes
• Metabolic diversity
  ○ Alternate energy sources: light, organics, inorganics
  ○ Alternate oxidants: O2, metals, CO2

Question 4

Key properties of eukaryotes (3)

Answer 4

• Larger size cells (10-25 um)
  ○ Complex structures
  ○ Multicells/tissues
• Flexible cell walls
  ○ Phagocytosis
  ○ Particle (organism) uptake
• Metabolic Specialisation
  ○ O2 respiration
  Organic C as fuel

Question 5

What is the gram stain for?

Answer 5

It indicates the type of cell wall that a bacterial cell possesses: either Gram positive or Gram negative

Question 6

What type of cell (gram neg or pos) do most characterized bacteria have?

Answer 6

Gram negative

Question 7

What is gram negative?

Answer 7

Cells have a thin cell wall in the periplasmic space between the cytoplasmic and the outer membrane

Question 8

What is gram positive?

Answer 8

Cells have a thick cell wall outside of the cytoplasmic membrane and do not have an outer membrane

Question 9

What types of bacteria are gram positive found in?

Answer 9

The Firmicutes and the Actinobacteria (including Bacillus sp.) including many invloved in biodegradations (e.g. Bacillus RHodococcus)

Question 10

Which type of cell wall holds the Gram stain? (turns purple?)

Answer 10

Gram positive

Question 11

What about cell walls and membranes of Archaea?

Answer 11

They are completely different from those of bacteria or Eucarya! They don’t contain peptidoglycan, but an S-layer

Question 12

Archaea characteristics summary (6)

Answer 12

• Live in mostly extreme environments (deep hydrothermal vent, hot springs)
• They can also be found living next to bacteria in your gut
• They share many similarities with Bacteria
• They are unicellular organisms, with no nucleus, like bacteria
• Cell wall do not contain peptidoglycan, but an S-layer (so no gram positive vs negative from what i understand)
• To this date, no Archaea has found to cause disease in humans

Question 13

What is a methanogen?

Answer 13

Produces methane (gen = genesis)

Question 14

What is a methanotroph?

Answer 14

Eats methane (troph = to eat)
aka they metabolize methane as their source of carbon and chemical energy