LIFE 103 1st Edition Lecture 3 Outline of Last Lecture II. Organizing the Diversity of LifeIII. Taxonomy a. Science of classifying things IV. Phylogenetic TreesV. Different Ways to ClassifyVI. Changes to ClassificationVII. Horizontal Gene Transfer and its Complicationsa. Movement of genes from one genome to another Outline of Current Lecture VIII.Problems with Bacteria and Archaea IX. Diversity X. TraitsXI. How does horizontal gene transfer work? XII. Examples of Archaea and Bacteria Current LectureII. Fig. 27.2 Why do we know so little about Bacteria and Archaea? III. They are very small a. 0.5 to 5 micrometers (μm)b. Most eukaryotic cells are 10-100 μm 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 culturableVI. 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 respirationf. Infect nearly any Eukaryote g. Live at temperatures >100 C Major Nutritional Modes Mode of Nutrition Energy Source Carbon Source AutotrophPhoto-autotrophChemo-autotrophHeterotrophPhoto-heterotrophChemo-heterotrophLight Inorganic Compounds Light Organic compounds CO2CO2Organic 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 transferXV. Parentoffspring (vertical gene transfer) XVI. Fig. 27.12 How does horizontal gene transfer work? XVII. Many bacteria contain additional DNA on plasmidsa. Transferred during conjugationXVIII. 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 extremophilesa. Usually grow in limited conditionsi. Hyper-salineii. Very high temperatures (up to 121 C)iii. Anoxic (no oxygen needed) XXII. Bacteriaa. Include the majority of prokaryotes that we know of XXIII. Check out table 27.2 Archaeal example: a Methane-producerXXIV. Methanosarcina acetivorans XXV. Lives in wetlands and other oxygen-free (anoxic) environments, rich in decomposing organic matterXXVI. Produces (“exhales) greenhouse gas methane Bacterial example: a pathogenXXVII. Yersinia pestis XXVIII. Causes plaguea. Killed 1/3 of Europeans around 1350 XXIX. Disease spread among infected individuals by fleasXXX. Infection most common among rodents, can spread to
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