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Unformatted text preview: Microbiology THE STUDY OF ORGANISMS THAT ARE TOO SMALL TO SEE WITHOUT THE AID OF A MICROSCOPE – Bacteria, Viruses, Fungi, Protozoa, Algae, Helminths Chapter 1 - The Main Themes of Microbiology I. Infectious Diseases and the Human Condition A. Infectious Disease vs. Noninfectious Disease New research indicates a connection in some cases - Diabetes and the Coxsackie virus; Schizophrenia and the Borna agent (a virus); MS, OCD, Coronary Artery Disease B. Statistics of Disease Occurrences 1. Most Common Infectious Disease in the US – Dental Caries in Children 2. Most Widespread Infectious Diseases Reported in the US (2008) – a) Chlamydia; b) HPV; c) Gonorrhea; d) Herpes simplex; e) Syphilis; f)Trichomoniasis; 3. Emerging Infectious Diseases – H1N1 Influenza 4. Highest Mortality in the US – a) Respiratory disease: Influenza and pneumonia; b) Septicemia 5. Highest Mortality Worldwide – a) Influenza and pneumonia; b) AIDS; c) Diarrheal diseases; d) TB C. Reducing the Spread of Pathogenic Microbes Hand washing; Disinfectants and Antiseptics; Aseptic technique II. General Characteristics of Microorganisms A. Cellular Organization – Two Basic Cell Types 1. Prokaryotic cells Simple cell structure – no nucleus; lack membrane-bound organelles ; Microscopic 2. Eukaryotic cells Complex cell structure – nucleus; membrane-bound organelles ; Larger than prokaryotes; some are microscopic 3. Characteristics shared by prokaryotes and eukaryotes – both have cytoplasm and 1) cell membrane, 2) ribosomes, 3) genetic material – ds DNA and ss RNA B. Viruses – DNA or RNA : No Cellular Organization: no nucleus ; viral particles: nucleic acid surrounded by a protein capsid and sometimes an envelope C. Size defined by use of the Metric System 1. Helminths – millimeters (mm) =10-3 m 2. Most microorganisms – micrometers ( μ m) =10-6 m 3. Viruses – nanometers (nm) = 10-9 m 1 III. Terminology Used in Studying Infectious Disease (Chapter 13) A. The Human Host 1. Most microorganisms are free-living and are not only harmless, but beneficial Saprobe - an organism that lives and obtains its nourishment from dead biological material 2. Other microorganisms are considered to be part of the normal biota – The Human Microbiome Project: using metogenomics to identify the microbial profile inside and on humans. a. Microbial antagonism – “good” bacteria benefit the human host by preventing the overgrowth of harmful organisms b. Intestinal flora research – tendency to be overweight: lower number of Bacteroidetes and higher number of Firmicutes (more calories from food); thinner individuals have the reverse c. Immunocompromised individuals can be infected with their own normal biota....
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- Fall '11