Download Phylogeny, Cell Structure and Flagella Study Guide and more Exams Nursing in PDF only on Docsity! EXAM 1 STUDY GUIDE CHAPTER 1 – PHYLOGENY, CELL STRUCTURE AND FLAGELLA| 2024 UPDATE SUCCESS ASSURED What’s the most recently determined kingdom? • Prokaryotes domain of life o Bacteria o Archaea • Simple forms of life? o No membrane bound nucleus o Devoid of organelles? ▪ Mitochondria, Golgi vesicles, etc. o Lack compartmentalization? false o No internal Skeleton? false The evidence for prokaryote complexity • Compartmentalization does exist o Granules containing enzymes for entire pathways o Membrane bound o Intermembrane compartments o Inclusion bodies storage • Cell poles are different o Flagella on one pole • Internal cytoskeleton similar to eukaryotes o Cell shape and division • Not just a “bag of enzymes” CHNOPS and trace minerals – major contribution of each • What are prokaryotes made out of? o Most biological molecules are made from covalent combinations of six important elements (CHNOPS) o Trace minerals (Ca, Mg, Mn, Mo, Fe, etc...) Origin of energy in bacteria • All energy on earth originates from solar energy through a metabolic “food chain” o Depending on the conditions of the niche and the neighboring organisms • Oxidation/Reduction reactions o Light bulb and battery • Derived from chemical reactions in the cytosol or membrane that generates proton gradients • How do microbes make a living? o Food (nutrition) ▪ Must have an adequate supply of CHNOPS and minerals o Housing (occupancy) ▪ Must be able to “beat out” others for a spot to live in an environmental niche (e.g. biofilm) o Protection (resistance) ▪ Must be able to defend against other microbes and eukaryotes that pose a threat Basic earth timeline and evolution of bacteria • Microbes have inhabited the planet for 80% of Earth’s history o Humans have only been around for ~1% of Earth’s history • Provides a lot of time for microbial pathways and niches to evolve way before higher plants and animals came on the scene • Only a few microorganisms are capable of existing without help from other organisms and vice versa o All rely on the sun’s energy in some way Important functions/impacts of microbes on humans • If microbes disappeared from the planet, life would cease o If humans no longer existed, microbes would not be impacted • All microbes require is sufficient water and nutrients o They can be found in every environment on earth • Vital to human health and biotechnology ➢ Functional gene diversity usually exceeds that detected at 16S rRNA ▪ Includes information on role of organism in environment What are the extreme environments Archaea are found in and their impact on humans • Extremophiles exist in some of the harshest environments on earth o Most extremophiles are Archaea o High pressure, High Salt, High temperature • Archaea impact on Humans o Biomedical research has relied on archaea ▪ Polymerase chain reactions uses DNA polymerase from Thermus aquaticus ▪ Bacteria (E. coli in particular) have also contributed ➢ Cloning, protein purification, etc… o Disease causing agents? ▪ Usual habitat for Archaea include ruminants and waste water plants ▪ No Archaea has been determined to act as a pathogen on either plants or animals ▪ Most antibiotics are ineffective against archaea Basic cell wall structure and differences between gram positive and gram negative bacteria • Cell Wall o Protect cell from bursting o Analyzed via Gram Stain works for most bacteria ▪ Mycoplasma bacterium WITHOUT a cell wall o Gram positive = stain purple o Gram negative = stain red • Bacterial Cell Wall Composition o Peptidoglycan ▪ β(1-4) linked GlcNAc (NAG) & MurNAc (NAM) ▪ Cleaved by lysozyme o Non-Peptidoglycan polymers ▪ Common in Gram positives ▪ E.g. teichoic acid = an acidic polysaccharide • Cell Wall Gram Stain o Invented by Christian Gram (1884) o Crystal violet-iodine stain o Gram positive thick peptidoglycan retains the stain o Gram negative outer membrane rich in phospholipids made “leaky” by alcohol and acetone o Archaea gram stain but different cell wall composition Cell membrane basic structure and functions • Cell Membrane o Generation of H+ gradient o Redox of NAD+ and FAD+ o Nutrient transport o Ion transport to maintain osmotic homeostasis o Protein secretion o Environmental signals o Flagellum rotation
