Option F:Microbes and Biotechnology

F.1 Diversity of Microbes

F.1.1 Outline the classification of living organisms into three domains

• 5 kingdoms: Bacteria, Protista, Plantae, Fungi, Animalia• Based on rRNA analysis, organisms were divided into three domains:

• Eubacteria: true bacteria

• Archaea: prokaryotes which live in extreme environments

• Eukarya: single-celled and multicellular organisms with a true nucleus

Example: E. Coli

Example: Thermophile

Example: Paramecium

F.1.2 Explain the reasons for the reclassification of living organisms into the three domains

• The 5 kingdom system was based on structural differences• The domain system looks at rRNA which is common in all organisms

(variation in nucleotide sequence)• Allowed us to better understand the evolution of eukaryotes

• Archaea and Eubacteria have:• Different cell wall components• Different structure of cell membranes• Different sequences of nucleotides in their rRNA

F.1.3 Distinguish between the characteristics of the three domains

Complete this table:

Eubacteria Archaea Eukarya

Histones

Introns

Ribosomes

Cell membranes

Cell Walls

Organelles

F.1.4 Outline the wide diversity of habitat in the Archaeabacteria as exemplified by methanogens, thermophiles and halophiles

Methanogens Thermophiles Halophiles

• Anaerobes• Uses CO2 to produce

CH4

• Ex: termite and cattle guts, Siberian tundra, large intestine of humans

• High temperatures (up to 105°C)

• Ex: sulfur hot springs, hydrothermal vents

• Saline habitats• Ex: dead sea,

evaporated water ponds

F.1.5 Outline the diversity of Eubacteria, including shape and cell wall structure

• Shape, cell wall, type of respiration

F.1.6 State, with one example, that some bacteria form aggregates that show characteristics not seen in individual bacteria

• Example: Bioluminescence in Vibrio fischeri• Bacterium no light• Aggregates light• High concentrations of signal expresses gene which

causes luminescence (Quorum sensing)

F.1.7 Compare the structure of the cell walls of Gram-positive and Gram-negative Eubacteria

Gram staining

F.1.8 Outline the diversity of structure in viruses including: naked capsid versus enveloped capsid; DNA versus RNA; and single-stranded versus double-stranded DNA or RNA

• Viruses: nucleic acid, enzymes, capsid

F.1.9 Outline the diversity of microscopic eukaryotes as illustrated by Saccharomyces, Amoeba, Plasmodium, Paramecium, Euglena and Chlorella