Ch 35: Prokaryotes, Evolution and Diversity of Bacteria
The domain Archaea includes...
halophiles - salt-loving -, acidophiles, and thermophiles. These tend to br found in extreme environments not generally colonised by members of the domain Bacteria or Eukarya.
Oxygenic photosynthesis, ...
in which oxygen is a product of the overall reaction to fix carbon dioxide as sugar, is also characteristic of modern eukaryotic algae and plants.
Antibiotics work by...
inhibiting processes or structural components in bacterial species at concentrations that fortunately do not affect eukaryotes. E.g. penicillins and cephalosporins target synthesis of bacterial cell wall peptidoglycan, a structural component not found in eukaryotic cell walls.
Once the earth's surface cooled, ...
molecular oxygen appeared in abundance in the atmosphere as a consequence of the development of oxygenic photosynthesis, a process that probably first appeared in bacteria about 2.5 bya.
Interestingly, the domain Archaea appears to be...
more closely related in evolutionary terms to the domain Eukarya than to the domain Bacteria.
The early lines of prokaryotes continued to evolve for...
more than 2 billion years before eukaryotes are thought to have appeared, and about 3 by before multicellular organisms appeared.
Ancient cyanobacteria are thought to have generated the first...
oxygen rich atmosphere on earth, which made the evolution of cellular metabolic pathways for oxidative metabolism possible.
The disposal inyo lakes, dams, and ...
slow-flowing streams of sewage and other wastes, or surface run-off from over-fertilized pastures and crops, sets the scene for serious cyanobacterial bloomd.
High concentrations of nutrients, particularly phosphate and potassium, in...
stationary or slow-moving water bodies, so that cells remain in the surface layers, capturing maximum light, promote blooms of this sort.
Many other biochemical and metabolic differences...
support recognition of the domains.
The appearance of abundant molecular oxygen in the atmosphere would have permitted...
the evolution of cellular metabolic pathways for the oxidative metabolism of organic carbon and reduced inorganic substrates, e.g. H2, H2S, NH3, Fe2+, of the sort that are common in most living organisms today.
Prokaryotes comprise...
two of these major branches, the Bacteria and the Archaea. The other lineage includes all the eukaryotes, collectively called the Eukarya. These three domains have also been referred to as super kingdoms.
Prokaryotes are so named because...
unlike eukaryotes, a true nucleus is absent. Prokaryotes, commonly termed bacteria, are the oldest and smallest cellular life on earth, they are single-celled organisms with a fossil record dating back to 3.6 mya.
The evolutionary age of bacteria and archaea, together with the varied habitats in which they live, has resulted in...
very high diversity.
These blooms are usually referred to as...
'blue-green algae' or 'toxic algae', a consequence of early misidentification of these organisms.
Currently, the most widely accepted authoritative taxonomic catalogue of bacteria is...
Bergey's Manual of Systematic Bacteriology. Sections are based on classic phenetic - phenotypic and ecological - characteristics and thus are not necessarily reflective of evolutionary relationships.t
Activity of Bacteria: Beneficial industry
Bioremediation of contaminated soils, pollutant removal and oil spill clean up.
Activity of Bacteria: Harmful Medical
Causation of: Sore throats, boils, cystitis, endocarditis, diphtheria, cholera, typhoid fever, dysentery, typhus, meningitis, chlamydia, gonorrhoea, syphilis, pneumonia, toxic shock, tetanus, botulism, tuberculosis, legionnaire's disease, wound infections, and many other important infectious diseases.
Gram stain with...
Crystal violet and iodine, wash with acetone-alcohol, and counterstain with carbol fuchsin, purple - gram positive bacteria, pink - gram negative bacter.
In the summer of 1991-92, ...
Extensive cyanobacteria blooms hundreds of kilometers long were reported on the Darling River. Towns and farms along the river had to be supplied with water from uncontaminated sources by tanker or had to install purification systems.
Beneficial activities associated with bacteria:
Humus formation, Antibiotic synthesis, Food production, Sewage treatment
Phenetic
Observe structural, ecological, and metabolic differences.
Bacteria may be able to remediate...
Pollutants, Oil, and Contaminated soils.
Comparisons between the three domains
Ribosome size: Domain Bacteria - 70S. Domain Archaea - 70S. Domain Eukarya - 80S. Peptidoglycan as major cell wall polymer: Only present in Domain Bacteria.
These toxins are...
Small peptides, 5 to 10 amino acids, and have their primary effects on liver metabolism. Swimming in toxin-contaminated water may cause serious skin and eye reactions.
Stromatolites formed from...
activities of large aggregations of cyanobacteria or more primitive filamentous phototropic bacteria, they are the oldest fossil evidence of life on earth.
While microbiologists still observe the phenotypic and ecological differences of cultures, assessing the diversity of...
bacteria and archaea today typically also involves molecular techniques carried out on specimens collected in nature.
The first to evolve were...
bacteria capable of anoxygenic photosynthesis
Pathogenic bacterial species can...
cause disease, not only in humans, but also in commercial plants and animals.
Species of cyanobacteria, such as Microcystis aeruginosa and Anabaena flosaquae, which...
form freshwater blooms of this sort, also produce toxins that are capable of causing illne and even death to animals and humans.
Introns and nucleus are...
found in eukaryotic cells, but not in prokaryotic cells.
