Procariotes diversity

CHAPTER 27
PROKARYOTES AND THE ORIGINS OF METABOLIC DIVERSITY
Prokaryotes are the most numerous and pervasive organisms on Earth. The evolution of prokaryotic life changed the Earth, and prokaryotes continue to have a major impact on all other forms of life. The success of prokaryotes is based on diverse adaptations of form and function, including all types of nutrition. There are two main kinds of prokaryotes: bacteria and archaea. Molecular systematics is leading to more detailed understanding of the relationships and roles of these important organisms.
Activities:
Modess of Nutrition in Prokaryotes
Prokaryotes can be grouped into four categories according to how they obtain energy and carbon. There are photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs. This bacterial growth chamber will allow you to test your knowledge of these prokaryote nutritional modes. Drag a petri dish to the chamber to choose a culture to grow. Then push buttons to choose the minimum factors-- an energy source and a carbon source-- that the selected bacteria need to live. Click "Check Answer" to see whether you have selected the correct factors to support growth of the bacteria you chose. Click "Reset" to start over.
Photoautotroph . You have selected the correct energy source and carbon source to support the growth of these bacteria.
Chemoautotroph. You have selected the correct energy source and carbon source to support the growth of these bacteria.
Photoheterotroph. You have selected the correct energy source and carbon source to support the growth of these bacteria.
Chemoheterotroph. You have selected the correct energy source and carbon source to support the growth of these bacteria.
Classification of Prokaryotes
Prokaryotic organisms are sometimes classified into two Domains instead of a single Kingdom (Monera). Domains are taxonomic groupings larger than a kingdom. There are approximately 12 subgroups within Domain Bacteria, five of which are shown here; Domain Archaea contains 3 major subgroups. To test your knowledge of prokaryotic subgroups, click on each question number at the bottom left of the screen. For each question, click on the correct subgroup for the bacterium shown in the box.
Anabaena circinalus is a freshwater photosynthetic bacterium, commonly seen growing in ponds in the summertime. Its bluish-green cells occur in chains. Specialized cells called heterocysts can fix nitrogen.Click on the subgroup that includes Anabaena. Cyanobacteria
Streptococcus aureus is a spherical bacterium with a thick cell wall of peptidoglycan. It occurs in chains. It is chemoheterotrophic and a facultative anaerobe. It grows on human skin and can be pathogenic. Click on the subgroup that includes Streptococcus. Gram positif bactyeria
Sulfulobus acidocaldarius is a rod-shaped bacterium that lives in hot springs at temperatures between 60 and 80 degrees C. It is a chemoautotroph that derives energy from oxidizing sulfur. Its cell walls are made of modified peptidoglycan (pseudomurein). Click on the subgroup that includes Sulfulobus. Extrime thermophiles
trachomatis is an obligate intracellular parasite that reproduces inside host cells. Its cell walls lack peptidoglycan. Cell shape varies but is never helical. This species causes nongonococcal urethritis, the most common sexually transmitted disease in the United States. Infection can result in blindness. Click on the subgroup that includes C. trachomatis. (Its full name is Chlamydia trachomatis). Clamidias
M. barkeri is a strict anaerobe found in swamps and sewage waste. It has an unusual chemoheterotrophic lifestyle, using H2 as an energy source and CO2 as the terminal electron acceptor in cellular respiration. The CO2 is reduced to CH4. Click on the subgroup that includes M. barkeri. (Its full name is Methanosarcina barkeri. Methanogens.
Proteus vulgaris is a chemoheterotroph that inhabits the intestinal tracts of animals and can be pathogenic. It is rod-shaped and a facultative anaerobe. The cell wall of this bacterium is fairly thin. Click on the subgroup that includes Proteus vulgaris. Proteo bacteria.
Treponema pallidum is a chemoheterotroph shaped like a long coiled spring or helix. It swims with a motion like a twirling corkscrew. This bacterium is the cause of syphilis, a common sexually transmitted disease. Click on the subgroup that includes Treponema pallidum. Spirochetes.
H. salinarium is an aerobic chemoheterotroph that lives in very salty ponds and lakes. Large numbers of this organism turn the water orange-red due to its internal pigment bacteriorhodopsin. The cell wall of H. salinarium is not made of murein. Click on the subgroup that includes H. salinarium. (Its full name is Halobacterium salinarium. Extreme halophiles.