Prokaryotes Bacteria vs Archaea Bacteria vs Archaea Classification

Prokaryotes: Bacteria vs. Archaea

Bacteria vs. Archaea

Classification of Bacteria and Archaea 1) Classification based on shape § 3 shapes: -Cocci = spherical -Bacilli = rod-shaped -Spirilli = spirals § Aggregation: -tendency to stick together in smalls groups

2) Classification based on the cell wall • Peptidoglycan -Chain-link combination of alternating amino acids and sugars -Gives rigidity to the cell wall (protects cell and gives it it’s shape) • Link to Penicillin - Penicillin affects the final formation of peptidoglycan. It binds to the molecule and stops the cell wall construction (destroys the bacteria, that is why it is used as an antibiotic!!)

• The importance of the Gram Stain v Bacteria only **Pink stain • Gram negative (–) – Majority of bacteria – Thin protein layer on their cell wall **Purple stain • Gram Positive (+) – Thick protein layer on their cell wall – Absorbs the stain v Information used in determining which antibiotics to use.

+ Thick protein layer on Cell wall

3) Classification based on nutrition • some bacteria use photosynthesis (autotrophs) ex. Cyanobacteria (blue-green algae) • archaea produce methane (methanogenesis) (autotrophs) ex. Live in digestive tract of cows to help digest cellulose and in turn produce methane. • Both heterotrophs ex. decomposers

» photosynthesis Cyanobacteria

4) Classification based on habitat • both live in aerobic and anaerobic conditions • Bacteria are mostly mesophiles -grow best in environments with moderate temperatures, not extreme • archaea can be extremophiles -live in extreme habitats -deep sea vents, hot springs -volcanic crater & mine drainage lakes -salt lakes

Reproduction of Archaea and Bacteria • Binary fission: -Result: cells with the same genetic material -Process: • Makes copies of its single chromosome • Cell elongates • Builds a partition (septum) – P. 301

• Conjugation (p. 302) -in less optimal conditions -ability to exchange DNA which results in cells with new genetic material

• Endospores (bacteria only) Endospore can withstand extreme conditions and heat.

• Creation of a hard walled structure that protect the genetic material -Resistant to high temperatures, freezing, a drying, toxic chemicals and radiation • Results in bacteria being able to remain dormant for very long periods of time

Bacteria vs. Archaea Summary Shape Bacteria Coccispherical Cell wall With Peptidoglycan Nutrition Autotrophs (photosynthesis) Habitat Mostly mesophiles Reproduction Binary fission Survival Tactics Conjugation Endospores Bacilli – rod Heterotrophs (predation) Spirilli- spiral shape Archaea Coccispherical Bacilli – rod Spirilli spiral shape Without peptidoglycan Autotrophs (methanogenesis) Heterotrophs (predation) Some extremophiles Binary fission Conjugation

Archaea and biotechnology • Archaea are currently used for: a) Sewage treatment b) Archaeaocin (new antibiotics) c) Enzyme production – Due to the extreme conditions they inhabit – Low lactose milk – Cloning DNA

Bacteria in Biotechnology • Bacteria are currently used for a) Food Production i)Cheese, yogurt b) Production of antibiotics c) Natural pesticides