BIOL 102 Lecture Notes - Lecture 13: Lipopolysaccharide, Lyme Disease, Cyanobacteria
14 Feb 2017
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Document Summary
R plasmids carry genes for antibiotic resistance. Antibiotics kill sensitive bacteria, but not bacteria with specific r plasmids. Through natural selection, the fraction of bacteria with genes for resistance increases in a population exposed to antibiotics. Antibiotic-resistant strains of bacteria are becoming more common. Diverse nutritional and metabolic adaptations have evolved in prokaryotes. Prokaryotes can be categorized by ho they obtain energy and carbon: phototrophs obtain energy from light, chemotrophs obtain energy from chemicals, autotrophs require co2 as a carbon source, heterotrophs require an organic nutrient to make organic compounds. Energy and carbon sources are combined to give four major modes of nutrition: photoautotrophy, chemoautotrophy, photoheterotrophy, chemoheterotrophy. Prokaryotic metabolism varies with respect to o2: obligate aerobes require o2 for cellular respiration, obligate anaerobes are poisoned by o2 and use fermentation or anaerobic respiration, facultative anaerobes can survive with or without o2. Nitrogen is essential for the production of amino acids and nucleic acids.
