Difference Between a Bateria and an Archaea
Bacteria:
1.
2.
3.
4.
RNA polymerase: Just one type (Consists of five subunits)
Peptidoglycan in cell wall: present
first amino acid incorporated during translation: is formylmethionine.
Histones associated with DNA: No
Side Note:
● Bacteria have a unique defense:
Bacterium (outer layer defence)
Endospore (inner layer defence)
Bacterial cells
Polysaccaride biofilm
●
Baterial cells (round):
Endospore:
Endospores are antibiotic resistant and can remain dormant for years.
Archaea
1. RNA polymerase: Just one type (Consists of 13 subunits; similar to RNA polymerase II
in eukaryotes)
2. Peptidoglycan in cell wall: Absent
3. First amino acid incorporated during translation: is methionine.
4. Histones associated with DNA: Yes
Koch’s Postulates
1. Mirobe present in diseased individuals and absent in healthy individuals
2. Microbe must be isolated and grown in pure culture
3. injection of microbes from this culture into healthy study animals must result in disease
Side Note:
Koch’s experiments are were essential in the development of the Germ Theory for
disease transmission
Morphological Diversity among Bacteria is extensive
1. Size varies:
Most bacteria are about 1 µm in diameter, but some are much larger
2. Sape varies
From rods to spheres to spirals in some species, cells adhere to form
chains (Rods, chains of spheres and spirals)
3. Motility varies
Some bateria are nonmotile, butswimming and gliding are common
Gram staining distinguishes two types of cell walls in bacteria.
1. Gram-positive:
Gram-positive cell wall (intense staining)
2. Gram-negative:
Gram-negative cell wall (little staining)
Gram stains stains the petidoglycan in the cell
Sources of Energy (for synthesis of ATP)
1. Cellular respiration:
● Cellular Respiration is based on electron transport chain (glucose is the
electron donor, and oxygen is the final electron acceptor)
●
This diversity of electron donors and acceptors is why bacteria are good at
remediation
2. Cellular respiration or fermentation:
3. Cellular respiration with inorganic compound as electron donor
Cyanobacteria Were the First Organisms to Perform Oxygenic Photosynthesis. (~2.3
BYA)
Some sulfur bacteria use H2S instead of H2O in their photosynthesis.
- a mutation allowed the switch to H2O for oxygenic photosynthesis to evolve
- since H2O is so much more abundant than H2S, oxygenic dominates
Lateral gene transfer and our gut flora
– informs are gut flora about what’s to come
• Oligosaccharides in mother’s milk
– we are incapable of digesting it
– Bacteria line the microvilli of our intestinal lining
●
Protects the lining as the gut flora is developed
Notes:
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all similar to the eukaryotes (Archaea ribosomes are also similar to eukaryotic
ribosomes)
Some archaea are etremophiles
Thermophilic Archaea are responsible for the yellow color of the yellow stone in yellow
stone National Park
Thermophilic Archaea are extremophiles
Almost all bacteria are beneficial. Only a small fraction cause disease.
Bacillus (rods)
Coccus( spheres)
Spirillus (spiral)
There are almost 700 Anoxic dead zones in our oceans