Lec 5 Bacter&Fungi 1- powerpoint with lecture notes EXAM 3

PROKARYOTES & VIRUSES Characteristics of the Prokaryotic Cell Diversity of Form Metabolic Diversity Reproduction and Gene Exchange Endospores Bacteria Archaea Viruses Viroids: Other Infectious Particles Origin of Viruses Three Major Forms of Prokaryotes bacillus (-bacilli) rod shaped spirillum (spirilla) spiral shaped coccus (cocci) sphere shaped Bacteria and Archaea Extremely small and ancient (3.5 billion years) Ubiquitous Lack an organized nucleus and membrane-bound organelles Circular strand of DNA localized at nucleoid Rigid cell walls (composed of peptidoglycan in Bacteria) Cell wall encased by ?capsule? of polysaccharide slime Store food in inclusions as poly-B-hydroxybutiric acid (lipid like) or glycogen (starch like) Distinct flagella Binary fission Clostridium botulinum survives boiling 7000 yr old lake sediments 25-40 million yr old amber ENDOSPORES Cyanobacteria Aerobic, Chl a Purple & Green Bacteria anaerobic, bacteriochlorophyll Gram-positive Bacteria retain crystal violet stain Genus Anabaena heterocyst Azolla Question: How could life before oxygen have evolved in such an extreme environment? Possible Answer: Many modern prokaryotes are hyperthermophilic, chemosynthetic, and adapted to life under pressure. Eukarya Bacteria Archaea Hyperthermophilic Eukarya Bacteria Archaea Chemosynthetic Photosynthetic Halophytic Archaea Methane-producing Archaea Thermophylic Archaea ?Taq? Tom Brock of the University of Wisconsin, discovered Thermus aquaticus in 1968 GENE AMPLIFICATION by Polymerase Chain Reaction (PCR) target gene Requires DNA to be denatured at ~96oC, but also requires DNA polymerase PROKARYOTES & VIRUSES Characteristics of the Prokaryotic Cell Diversity of Form Metabolic Diversity Reproduction and Gene Exchange Endospores Bacteria Archaea Viruses Viroids: Other Infectious Particles Origin of Viruses