BIOL 112 Lecture 17

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Archaea

Like bacteria:

• No membrane-bound organelles
• Circular DNA; no nuclear envelope

Like eukaryotes:

• Histone-like proteins associate with DNA
• Introns
• Multiple polymerases
• not sensitive to antibiotics (cell wall doesn't have peptidoglycans)

Unique to themselves:

• rDNA sequence
• extremophiles
• cell wall and membrane have unusual composition and structure

Role of Prokaryotes

chemical recycling

• nitrogen, carbon, iron, and sulfur fixation for use by other organisms
• decomposition of dead organisms; release elements and compounds back into environment

Symbiosis

mutualism

positive-positive

host and symbiont both benefit

e.g. intestinal E. coli (bacteria secrete antimicrobial compound, produce important compounds, stimulate blood flow and absorption; host provides food and safe environment)

parasitism

positive-negative

symbiont benefits at cost of host

e.g. diseases like tuberculosis, diarrhea, salmonella, lyme disease

Microbiology

1. Polymerase Chain Reaction (PCR): DNA amplification by heat-stable polymerase enzyme from thermophiles
2. Restriction Enzymes: cut DNA at known specific sequences
3. Biol-remediation or alternative fuels