MICROBIO 4000 EXAM 1 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

MICROBIO 4000 EXAM 1 QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 What did Robert Hooke report and in what year? - Answers 1665; reported that living things are composed of little boxes, or cells Define cell theory - Answers All living things are composed of cells and come from preexisting cells What did Anton van Leeuwenhoek do? - Answers first observed and described live microorganisms What is spontaneous generation? - Answers the hypothesis that living organisms arise from nonliving matter What is biogenesis? - Answers the hypothesis that living organisms arise from preexisting life (Pasteur, Tyndall) How long did it take to disprove spontaneous generation of microorganisms and why? - Answers 200 years, One reason: conflicting results between laboratories What did John Needham do and when? - Answers In 1749, he demonstrated that boiled broths still produced microorganisms What did Spallanzani do afterwards? - Answers contradicted Needham's results by Boiling broths longer; sealed flasks by melting necks, Broths remained sterile unless neck cracked What did Louis Pasteur do and when? - Answers 1861: demonstrated that microorganisms are present in the air How did Pasteur go on to disprove spontaneous generation? - Answers Boiled infusions remained sterile despite opening to air, Ended arguments that unheated air or broths contained "vital force" necessary for spontaneous generation, results not fully reproducible What did John Tyndall do? - Answers finally explained conflicting data and proved Pasteur correct. Sterilizing broths required different times (some sterilized in 5 minutes, Others not despite 5 hours!) What did Tyndall realize about broths? - Answers broths made from hay contained heat-resistant microbes What did Ferdinand Cohn discover and when? - Answers 1876, discovered endospores What are the steps of the Scientific Method? - Answers -Make an observation •Develop a testable explanation called a hypothesis •Design experiments to test the hypothesis •Do the experiment, collect and analyze data •Draw a conclusion •Communicate methods, results and conclusions What is a scientific theory? - Answers an explanation supported by a large amount of evidence. What sparked the Golden Age of Microbiology? - Answers As spontaneous generation was disproved What is the Germ Theory of Disease? - Answers The principle that microorganisms cause diseases What did the Germ Theory of Disease consist of? - Answers -Most pathogenic bacteria identified () -Work on viruses began -Understanding that microscopic agents could cause disease led to control efforts -Huge improvements in human health •Antibiotics to treat infectious diseases •Vaccines to prevent diseases What years encompass the Golden Age of Microbiology? - Answers What did Joseph Lister do during the Golden Age? - Answers Applying Pasteur's work showing microbes are in the air, and can spoil food, Joseph Lister used a chemical disinfectant (phenol) to prevent surgical wound infections What did Robert Koch do during the Golden Age? - Answers proved that a bacterium causes anthrax and provided the experimental steps, Koch's postulates, to prove that a specific microbe causes a specific disease What did Edward Jenner do and when? - Answers Jenner inoculated a person with cowpox virus, who was then protected from smallpox. Introduction of a concept of vaccination. (vacca=cow) Benefits of Microorganisms - Answers nitrogen fixation, oxygen production, degradation of materials Name the applications of Microbiology - Answers food production, biodegradation, bacteria synthesize commercially valuable products, biotechnology, genetic engineering How is microbiology used in food production? - Answers Fermentation : Dairy products, alcoholic beverages How is microbiology used in biodegradation? - Answers Degrade DDT, trichloroethylene and others. Help clean up oil spills, Bioremediation: using microorganisms to hasten decay of pollutants How is microbiology used to produce commercially valuable products? - Answers Hydroxybutyricacid (manufacture of disposable diapers and plastics), Ethanol (biofuel), Insect toxins (insecticides), Antibiotics (treatment of disease) How is microbiology used in biotechnology? - Answers Use of microbiological and biochemical techniques to solve practical problems How is microbiology used in genetic engineering? - Answers Introduction of genes into another organism, Production of medications (e.g., insulin for diabetes) What is the issue with emerging diseases and name a few - Answers Changing lifestyles increase opportunities to spread (Closer contact with animals), Evolution of infectious agents previously unable to infect humans. EX. swine flu, ebola, AIDS What can we contribute to re-emerging diseases? - Answers Vaccinations becoming victim of own success, Lack of firsthand knowledge of dangers of diseases can lead people to fear vaccines more than the diseases, Pathogens can become resistant to antimicrobial medications, Increased travel and immigration, Changes in population What are benefits of microbes? (beneficial microbes) - Answers Termed normal microbiota or normal flora, prevent diseases by competing with pathogens, development of immune system response, Aid in digestion What do pathogens do to the human body? - Answers damage body tissue and cause disease symptoms What are the two basic cell structures? - Answers Prokaryotes do not have a membrane-bound nucleus, Eukaryotes have a membrane-bound nucleus and organelles All living things can be classified into one of three groups, or domains: - Answers Bacteria Archaea Eukarya bacteria characteristics: - Answers - Single-celled prokaryotes -Prokaryote = "prenucleus" -No membrane-bound nucleus -No other membrane-bound organelles -DNA in nucleoid -Most have specific shapes (rod, spherical, spiral) -Rigid cell wall contains peptidoglycan(unique to bacteria) -Multiply via binary fission -Many move using flagella archaea characteristics: - Answers Like Bacteria, Archaea are prokaryotic -Similar shapes, sizes, and appearances to Bacteria -Multiply via binary fission -May move via flagella -Rigid cell walls However, major differences in chemical composition -Cell walls lack peptidoglycan -Ribosomal RNA sequences different Many are extremophiles -High salt concentration, temperature eukarya characteristics: - Answers Eukaryotes= "true nucleus" -Membrane-bound nucleus and other organelles -More complex than prokaryotes -Microbial members include fungi, algae, protozoa •Algae and protozoa also termed protists •Some multicellular parasites including helminths(roundworms, tapeworms) considered as well Characteristics of nomenclature: - Answers two words, Genus(capitalized), specific epithet, or speciesname (not capitalized), Genus and species always italicized or underlined, may be abbreviated •E.g., Escherichia coli OR Escherichiacoli What are the two most common shapes of prokaryotic cells? - Answers Spherical: cocci (a coccus) Rods: bacilli (a bacillus) What are the other shapes of prokaryotic cells? - Answers Vibrio, spirillum, Spirochete monomorphic vs. pleomorphic - Answers one form vs. alter shape into different forms How do most prokaryotic cells divide? - Answers by binary fission and cells often stick together following division what are the 3 major cell arrangements and their prefix? - Answers Chains: Diplo-, Strepto- Packets: Tetrads, Sarcinae Clusters: Staphylo- What are the main characteristics of a prokaryotic cell wall? - Answers Cell wall is a strong, rigid structure, is the basis for distinguishing two main types of bacteria (Gram-positive/Gram-negative), Made from peptidoglycan (only found in bacteria) What are the parts of Peptidoglycan? - Answers Glycan chains subunits •N-acetylmuramicacid (NAM) •N-acetylglucosamine(NAG) Tetrapeptidechain (string of four amino acids) Peptide bridges or crosslinks A Gram-positive cell wall has: - Answers Thick peptidoglycan layer and teichoic acids A Gram-negative cell wall has: - Answers very thin peptido-glycan layer in periplasmic space and a unique outer membrane Describe the outer membrane bilayer of the gram-negative cell wall: - Answers lipopolysaccharide(LPS) containing Lipid A (immune system recognition), O polysaccharide (identify species or strains) and Porins What is the medical significance of the unique outer membrane? - Answers LPS (lipid A) is endotoxin, blocks passage of many molecules including certain antibiotics At the end of the gram staining procedure what color to the gram negative cells appear? - Answers pink At the end of the gram staining procedure what color to the gram positive cells appear? - Answers purple What bacteria lack a cell wall? - Answers Mycoplasma species: extremely variable shape Penicillin, lysozyme do not affect these What bacteria contain an acid fast cell wall? - Answers Waxy lipids, such as mycolic acids These are not affected by many antibacterial substances Characteristics of the cytoplasmic membrane of a prokaryotic cell: - Answers Semipermeable membrane: controls movement Composition: Phospholipid bilayer with proteins Fluid mosaic model What are the functions of the cytoplasmic membrane? - Answers Selective gates, Sensors of environmental conditions, Enzymes for ATP synthesis (Electron Transport Chain and Proton Motive Force) The cytoplasmic membrane is selectively permeable because: - Answers O2, CO2, N2, small hydrophobic molecules, and water pass freely through lipid layer but other molecules must be moved across membrane via transport systems (carriers, permeases) What are the two types of transport across Cytoplasmic Membrane? - Answers passive transport and active transport Characteristics of passive transport: - Answers Along the concentration gradient, does not require energy, Examples: Simple diffusion, Osmosis, Facilitated diffusion Characteristics of active transport: - Answers Against the concentration gradient, Requires energy, Examples: Active Transport using either PMF or ATP, Group Translocation Simple diffusion - Answers Movement of solute from high to low concentration, Speed depends on concentration- used by prokaryotes Osmosis - Answers Diffusion of water across selectively permeable membrane due to unequal solute concentrations, Three terms to describe conditions outside the cell: -Hypertonic -Isotonic -Hypotonic Used by prokaryotes Hypotonic - Answers Water moves inside the cell: osmotic lysis Hypertonic - Answers Water moves outside the cell: Plasmolysis Isotonic - Answers No net movement of water Active transports two main mechanisms: - Answers 1. Use proton motive force 2. Use ATP (ABC transporter) Group translocation - Answers transporter chemically alters the substance as it is transported across the membrane- includes phosphorylation & is unique to bacteria Facilitated diffusion - Answers transporter allows a substance to more across the membrane, but only down its concentration gradient- rarely used by prokaryotes What is a capsules/slime layer? - Answers Gel-like layer outside cell wall in some bacteria What is a capsule/slime layer made of? - Answers Mostly glycocalyx(sugar shell); some polypeptides What are the functions of the capsule/slime layer? - Answers Adherence: biofilm (Polysaccharide encased community), Increased virulence: evade host immune system, Dehydration, Nutrients Flagella - Answers Filamentous Protein Appendages that are not essential but give advantages Characteristics of flagella: - Answers Flagella involved in motility- spin like propellers to move cell, some important in disease, numbers and arrangements help with characterization What are the three parts of flagella? - Answers filament, hook, basal body Chemotaxis of flagella: - Answers Bacteria sense chemicals and move accordingly 1)Nutrients may attract, toxins may repel 2)Movement is series of runs and tumbles