BIOL 152 9thEdition Lecture 9 Outline of Last Lecture I Morphological and Molecular Homologies II Sorting Homology from Analogy III Evaluating Molecular Homologies Outline of Current Lecture I Cell Surface Structures II Gram Staining III Motility movement IV Internal Organization and DNA V Reproduction and Adaptation Part 2 I Genetic Recombination II Transformation and Transduction III Conjugation and Plasmids Part 3 I II The Role of Oxygen in Metabolism Nitrogen Metabolism Current Lecture Prokaryotes o Archaea and Bacteria nucleus deprived 27 1 Structural and Functional Adaptations Contribute to Prokaryotic Success I Most unicellular MOST Most 0 5 5 m 10 100 m eukaryotic cells Variety of shapes Most common spheres cocci rods bacilli and spiral Cell Surface Structure o Cell Wall Bacteria peptidoglycan Archaea polysaccharides and proteins Eukarya cellulose and chitin 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 II III o Function Shape protection doesn t expand in hypotonic area Gram Staining o Classify Bacteria 2 outcomes positive and negative o Gram positive simpler walls w lots of peptidoglycan Antibiotics attack peptidoglycan DNA replication transcription and translation differences o Gram negative less peptidoglycan Outer membrane can be toxic More likely to be antibiotic resistant o Capsule polysaccharide or protein layer Allows to stick to things More protection o Fimbriae hair like structures sticky o Pili sex pili exchange DNA remember gene transfer Made of proteins chain of proteins Motility Movement o Taxis movement and toward or away o Chemotaxis Positive towards some chemical Negative away from some chemical o Flagella meant for movement Evolutionary Origins of Bacterial Flagella Flagella proteins modified versions of other proteins o Mutation of DNA Likely evolved while proteins were added to ancestral secretory system Exaptation existing structures take on new functions through evolution o Ex porcupines had fur fur turned into spikes for protection IV Internal Organization and DNA o Prokaryotes usually lack complex compartmentalization Some may have infoldings of the plasma membrane o Genetic Info Shorter than eukaryotes Nucleiod region Circular DNA Plasmid smaller circles of DNA V Reproduction and Adaptation o Key features of prokaryotic reproduction They are small They reproduce by binary fission They have short generation times 1 3 hrs Fast evolution highly evolved o Endospores 27 2 Rapid reproduction mutation and genetic recombination promote genetic diversity in prokaryotes Prokaryotes have considerable genetic variation 3 Factors contribute to this genetic diversity o Rapid reproduction o Mutation o Genetic recombination I Genetic Recombination combining of DNA from 2 sources Contributes to diversity o 3 Processes Transformation Transduction through viruses Conjugation sex o Horizontal gene transfer movement of genes between different species II Transformation and Transduction o Transformation DNA from surrounding environment o Transduction bacteriophages III Conjugation and Plasmids o Conjugation bacteria sex o F Factor what does F stand for o If present pilus o If not receiver o The F can transfer o Non sequilur R plasmids and Antibiotic Resistance 27 3 Diverse Nutritional and Metabolic Adaptations Have Evolved in Prokaryotes Prokaryotes can be categorized by how they obtain energy and carbon o Energy Phototrophs Chemotrophs o Carbon Autotrophs Heterotrophs I The Role of Oxygen in Metabolism o Prokaryotic metabolism varies with respect to O2 II Obligate aerobes Obligate anaerobes Facultative anaerobes Nitrogen Metabolism o N needed for what o Nitrogen fixation N2 to NH3 ammonia o Mutalisms Cyanobacterium Anabaena photosynthetic cells and nitrogen fixing cells called heterocysts or heterocysts Biofillms surface coating colonies