LIFE 103 1st Edition Lecture 3 Outline of Last Lecture II Organizing the Diversity of Life III Taxonomy a Science of classifying things IV Phylogenetic Trees V Different Ways to Classify VI Changes to Classification VII Horizontal Gene Transfer and its Complications a Movement of genes from one genome to another Outline of Current Lecture VIII Problems with Bacteria and Archaea IX Diversity X Traits XI How does horizontal gene transfer work XII Examples of Archaea and Bacteria Current Lecture II Fig 27 2 Why do we know so little about Bacteria and Archaea III They are very small a 0 5 to 5 micrometers m b Most eukaryotic cells are 10 100 m IV It is hard to study things that are so small V We learn best by culturing but 99 of bacteria and Archaea are not culturable VI Starting to learn about uncultured diversity by studying DNA from different environments Bacteria and Archaea have TREMENDOUS physiological diversity VII Different species can be found that can a Live in pH 1 or 12 b Photosynthesize c Convert atmosphere N2 unavailable to plants to ammonium available to plants d Degrade many many organic compounds These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute e Use rust iron oxide instead of O2 in respiration f Infect nearly any Eukaryote g Live at temperatures 100 C Major Nutritional Modes Mode of Nutrition Autotroph Photo autotroph Chemo autotroph Heterotroph Photo heterotroph Chemo heterotroph Energy Source Carbon Source Light Inorganic Compounds CO2 CO2 Light Organic compounds Organic Compounds Organic compounds Oxygen in metabolism VIII Burning oxygen in cell metabolism releases the most energy from food IX But some bacteria and Archaea can use other oxidants a Nitrate NO3 Sulfate SO4 oxidized iron What traits allow such diversity X Small size XI Rapid generation time some 20 minutes generation time XII Endospores durable resting stage to wait out hard times XIII Small light spores are easily dispersed to new habitats XIV Horizontal gene transfer XV Parent offspring vertical gene transfer XVI Fig 27 12 How does horizontal gene transfer work XVII Many bacteria contain additional DNA on plasmids a Transferred during conjugation XVIII Bacteria pick up DNA directly from their environment XIX Viruses move DNA between bacteria XX If a non pathogenic bacterium became resistant to an antibiotic could that pose a human health risk a Yes because the gene could be transferred to a pathogenic bacterium Bacteria and Archaea XXI Archaea the extremophiles a Usually grow in limited conditions i Hyper saline ii Very high temperatures up to 121 C iii Anoxic no oxygen needed XXII Bacteria a Include the majority of prokaryotes that we know of XXIII Check out table 27 2 Archaeal example a Methane producer XXIV Methanosarcina acetivorans XXV Lives in wetlands and other oxygen free anoxic environments rich in decomposing organic matter XXVI Produces exhales greenhouse gas methane Bacterial example a pathogen XXVII XXVIII Yersinia pestis Causes plague a Killed 1 3 of Europeans around 1350 XXIX Disease spread among infected individuals by fleas XXX Infection most common among rodents can spread to humans
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