Biology reading for 2/4/15 Pages 135-138Diverse Nutritional and Metabolic Adaptations have evolved ProkaryotesProkaryotes can be categorized by how they obtain energyPhototrophs: Organisms that obtain energy from lightChemotrophs: organisms that obtain energy from chemicalsAutotrophs: Organisms that need CO2 or related compounds as a carbon sourceHetrotrophs: Require at least one organic nutrient, such as glucose, to make other organic compoundsThe role of oxygen in metabolismObligate aerobes: Must use oxygen for cellular respiration and cannot grow without itObligate anaerobes: Poisoned by oxygenSome obligate aerobes live exclusively by fermentation while others extract chemical energy by anaerobic respirationAnaerobic respiration: A catabolic pathway in which inorganic molecules, other than oxygen, accept electrons at the “downhill” end of the electron transport chainsMajor Nutritional ModesMode Energy Source Carbon Source Types of OrganismsAUTOTROPHPhotoautotroph Light CO2, HCO3, or related compoundPhotosynthetic prokaryotes; plants, or certain protistsChemoautotroph Inorganic chemicals CO2, HCO3, or related compoundsUnique to certain prokaryotesHETEROTROPHPhotoheterotroph Light Organic compounds Unique to certain aquatic and salt-loving prokaryotesChemoheterotroph Organic compounds Organic compounds Many prokaryotes, protists, fungi, animals, and some plantsFacultative aerobes: Use oxygen if it’s present, but can also carry out fermentation or anaerobicrespiration in an anaerobic environmentNitrogen MetabolismNitrogen is essential for the production of amino acids and nucleic acids.Eukaryotes can obtain nitrogen from a limited group in many forms.Nitrogen fixation: The conversion of atmospheric nitrogen to ammoniaMetabolic CooperationHeterocysts: Cells that carry out only nitrogen fixationBiofilm: Surface-coating colonies that often contains metabolic cooperationProkaryotes have radiated into a diverse set of lineagesAn overview of prokaryotic DiversityDomains: Eukarya, Archaea, BacteriaEukarya: EukaryotesArchaea: Korarchaeotes, Euyarchaeotes, crenarchaeotes, NanoarchaeotesBacteria: Proteobacteria, chlamydias, Spirochetes, Cyanobacteria, Gram-positive bacteriaBacteriaProteobacteria: A diverse clade of gram-positive bacteria including photoautrophs, chemoautotrophs, and heterotrophsThe five subgroups of proteobacteria: alpha, beta, gamma, delta, epsilonAlpha Proteobacteria: Many are associated with eukaryotic hosts.Beta Proteobacteria: a nutritionally diverse subgroup that includes nitrosomonas, rubrivivax, and Neisseria gonorrhoeaeGamma Proteobacteria: Includes the slime-secreting myxobacteriaEpsilon proteobacteria: Mostly pathogenic to humans and animals. Includes campylobacter, and Helicobacter pylori. Quizlet Link: