Microbiology Chapter 1-6 Test Questions and Answers

Microbiology Chapter 1-6 Test Questions and Answers Microorganisms are entities that are too small to be seen with the unaided eye. Examples of Microbes Bacteria, Viruses, Protozoa, Fungi, Algae, and Larvae of Helminths Pathogenic Microbes cause disease. Microorganisms are Beneficial They: Decompose Waste Are producers of oxygen by photosynthesis Provide a food source for many other organisms Produce fermented foods such as vinegar, cheese and bread Produce anitbiotics and vaccines Microorganisms are Beneficial by Producing industrial chemicals such as ethyl alcohol, acetone, and enzymes used in cleaners. Linneaus established the system of scientific nomenclature. Genus and Species Two names of any organism. Serotypes Most bacterial species contain subspecies or what which are variations within a species. Three Domains Eubacteria Archaea Eukaryotes Bacteria Prokaryotes Unicellular Peptidoglycan is found in their cell wall Reproduce by binary fission Extremely diverse What do bacteria do for energy? For energy, bacteria may use organic chemicals, inorganic chemicals, or photosynthesis depending on species. Archaea Prokaryotes similar to bacteria Unicellular Lack peptidoglycan Usually live in extreme environments Have not changed structure and physiology for centuries Fungi Eukaryotes Chitin in cell walls Use organic chemicals for energy (not photosynthetic) Larger than bacteria, some reproduce sexually Many produce reproductive structures like mushrooms and sporangia. Protozoa Eukaryotes Absorb or ingest organic chemicals Very few species are photosynthetic Some are serious parasites in humans Mostly unicellular and motile via pseudopods, cilia, or flagella Algae Eukaryotes Cellulose cell walls Unicellular and Multicellular forms usually found in aquatic systems Use photosynthesis for energy Produce molecular oxygen and organic compounds Are a food source for many organisms Viruses Acellular (non-living) Consist of DNA or RNA core Obligate intracellular parasites When are viruses replicated? Viruses are only replicated when they are in a living host cell Helminths Eukaryotes Multicellular animals; most are not parasitic When were the first microbes observed? 1600s Robert Hooke 1665; reported that living things were composed of cells. Cell Theory all living things are composed of cells and come from preexisting cells. Antoni Van Leeuwenhoek 1673; observed and described living microorganisms. He observed teeth scrapings, rain water, and peppercorn infusions. Louis Pasteur "Father of Microbiology" 1861; he demonstrated that microorganisms are present in the air with his S-shaped flask Disproved spontaneous generation Pasteurization Pasteur demonstrated that these spoilage bacteria could be killed by heat that was not hot enough to evaporate the alcohol in wine. Ignaz Semmelwise 1840s; advocated hand washing to prevent transmission of pueperal fever from one OB patient to another. Joseph Lister 1860s; used a chemical disinfectant to prevent surgical wound infections. Robert Koch 1876; provided proof that a bacterium, (Bacillus anthracis) causes Anthrax and developed his own postulates. Koch Postulates used to prove that a specific microbe causes a specific disease. Edward Jenner noticed that milkmaids never contracted smallpox, he believed due to their exposure to cowpox. 1796; he inoculated a person with cowpox virus to protect them from smallpox virus. Antibiotics chemicals produced by bacteria and fungi that inhibit or kill other microbes. Paul Ehrlich 1910; developed and synthetic arsenic drug, salvarsan, to treat syphilis. Sulfonamides 1930s; were synthesized and are commonly prescribed as sulfa-drugs Alexander Fleming 1928; discovered the first antibiotic on accident; penicillin. Biotechnology is the use of microbes to produce food and chemicals Genetic Engineering through this, bacteria and fungi can produce a variety of proteins including vaccines and enzymes. Gene Therapy missing or defective genes in human cells can be replaced by this. Genetically Modified Bacteria are used to protect crops from insects and freezing. Resistance the ability of the body to ward off disease. Zaccharias Janseen is credited with making the first compound microscope in the 17th century. Joseph Listers Father made the first one capable of viewing microbes in the mid-19th century. Compound Microscope the image from the objective lens is modified again by an ocular lens. Illuminator Light source Condenser lenses that direct light rays through the specimen. Resolution the ability of the lenses to distinguish two points and fine detail and structure. Refractive Index is a measure of the light-bending ability of a medium. Immersion Oil is used to keep light from bending. Brightfield Illumination Dark objects are visible against a bright background Most small specimens are killed and stained with colored dyes. Some larger and motile specimens may be viewed. Darkfield Illumination Light objects are visible against a dark background Used to examine living or unstained organisms suspended in liquid. Smear a thin film of a solution of microbes on a slide Chromophore dye that carries a charged particle Mesophiles 25-40 degrees celsius Thermophiles 70-80 degrees celsius Pyschrophiles 15 degrees celsius Psychrotrophs 22 degrees celsius Carbon is required by all organisms to form structural organic molecules and as an energy source. Nitrogen is a limiting factor in many ecosystems and is found in amino acids and proteins Sulfur is found in amino acids, thiamine, and biotin. Phosphorus is found in DNA, RNA, ATP, and membranes. Oxygen is utilized by obligate aerobes and facultative anaerobes Obligate Anaerobes need the absence of O2; many are killed by it. Facultative Anaerobes can also grow without oxygen (many are fermenters) Microaerophiles require strict limited amounts of O2 to survive. Reproducing Media contain chemicals that combine O2. Culture Media nutrients prepared for microbial growth. Sterile no living microbes