MICRO Exam 1 study guide
MICRO Exam 1 study guide Micro 2123
Popular in Introduction to Microbiology
verified elite notetaker
Popular in Microbiology
This 6 page Study Guide was uploaded by Meredith McKnight on Sunday August 28, 2016. The Study Guide belongs to Micro 2123 at Oklahoma State University taught by Noha H. Yousseff in Fall 2016. Since its upload, it has received 143 views. For similar materials see Introduction to Microbiology in Microbiology at Oklahoma State University.
Reviews for MICRO Exam 1 study guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 08/28/16
Introduction to Microbiology Study Guide EXAM 1 Highlight= on exam review posted by Yousseff Chapter 1 & 2- The microbial cell and how to observe it Microbes o Living organism o Range in size from a few nanometers to a fraction of a millimeter in size o Found in 3 domains of life: Bacterium Archaea Eukarya Microscopes o Microscopes increase resolution by increasing magnification Resolution- the smallest distance by which two objects can be separated but still be distinguished o Light microscopy- uses light to resolve images of individual cells 4 types: Bright-field, dark-field, fluorescence, phase contrast Bright-field Images viewed as dark against a light filled field Resolution enhanced via fixation and staining o Staining- cells given distinct color Differential stain names: gram, acid-fast, spore, negative o Fixation- cells adhered to slide Dark-field Objects are halos of light against dark background Employs light scattering property of light higher resolution than bright field requires modified condenser to detect Phase Contrast Uses refractive light Used to view cells and organelles Reveals differences in refractive index as light/dark patterns Fluorescence Uses fluorophore stain Fluorophore absorbs light in one color and emits in another Incident light is absorbed by specimen and remitted at a longer wavelength o Electron microscopy- uses electrons to resolve images. Electrons act like light waves 2 types: Scanning (SEM) and Transmission (TEM) Specimens treated with heavy metal coating so they absorb electrons SEM- electrons scan the surface of the sample o Shows external structures in 3D TEM- electrons pass through sample o Samples sliced and coated o Shows internal structures in 2D Chapter 3- cell structure and function Cell model o Cytoplasm, cell membrane, cell wall, internal nucleoid, external structures (flagella, pili, sex pili) Cell membrane o Functions: Defines existence of cell Structural support Detection of environmental signals Secretion of virulence factors and communication signals Ion transport & energy storage o Semi-permeable Phospholipid bilayer containing proteins (transport proteins: active/passive) that act as doors for larger molecules to enter Cell wall (envelope) o Function: Outer layer of cell Gives shape Withstand turgor pressure o Made of peptidoglycan Peptidoglycan made of repeating disaccharide units of NAM (N- acetylmuramic acid) and NAG (N-acetylglucosamine) and amino acids (Peptido)- small proteins (amino acids) o 4-6 amino acids that act as cross linkage between parallel strands of NAM and NAG (glycan strands) (glycan)- sugar o NAG and NAM parallel strands o Gram positive and Gram negative Gram positive- thick cell wall (more layers of peptidoglycan) stains purple No LPS layer Gram negative- thin cell wall (1-2 layers peptidoglycan) don’t retain purple stain have outer membrane of LPS (lipopolysaccharide) which constitutes most of outer membrane appear as a triple layer in TEM pictures LPS Made of lipid A, core polysaccharide, and O-antigen or O-oligosaccharide Nucleiod Region of prokaryotes that contain DNA of cell- “nametag” Pili/fimbriae- straight protein filaments used to adhere to surfaces Sex pili- used in DNA transfer from a donor to recipient cell (conjugation) Flagella- allows for motiliy Chapter 4- bacterial culture and growth/nutrition Nutrients- cell membrane mostly impermeable to nutrients o Macronutrients- major elements in cell macromolecules (carb, lipid, protein) ex: C, O, H, N, P, S. and ions necessary for protein function ex: Mg 2+, Ca 2+ o Micronutrients- trace elements necessary for enzyme function Nutrient Transport o Diffusion- molecule passes through membrane without help of protein o Passive transport- (protein required) follow concentration gradient (high to low) no energy required cannot go against gradient o Active Transport Active coupled Transport Energy released by moving a driving ion down its gradient is used to move a solute up its gradient Symport- molecules travel same direction Antiport- molecules travel opposite direction Active ABC transporters (ATP binding cassette superfamily) energy from ATP hydrolysis uptake ABC- transporters critical for nutrient transport efflux ABC- transporters used as multidrug efflux pumps Group Translocation (PTS System) Energy required Chemically alters substrate during transport Present in all bacteria Growth/Culture o Generation time- the time it takes for a population to double o Growth phases Lag- prepare for growth Log-actual growth Stationary- no growth; activates stress response Death- no nutrients; starts to die off o Media Complex- nutrient rich; poorly defined. Ex: yeast Synthetic- precisely defined Selective- one organism grows but another won’t Differential- exploits differences between 2 species; they grow equally well but display different phenotypes o Pure Culture techniques (recognize diagrams) Dilution streaking- dragging loop across surface of agar plate Spread plate- tenfold serial dilutions are performed on liquid culture and small amount of dilution plated. Endospores- o resistant forms made by bacillus and clostridium o contain DNA o germinate when conditions are favorable Biofilm o Resistant structure starts with attachment to surfaces Chapter 5- microbial growth Extremophiles- any microbe that grows outside normal conditions o Normal conditions: Sea level 20-40 C Neutral pH .9% salt Ample nutrients o Survive because proteins and membranes (macromolecules) are intact and functional in extreme conditions. Fastest growth occurs when proteins most functional o Prefixes- Temperature- psychro, meso, thermo, hyperthermophiles Pressure- barophile, barotolerant Salt- halophile Oxygen- aerobe, anaerobe, microaerophile, facultative anaerobe o On exam, for extremophile name combinations an organism can have one of each type of prefix ex: psychrobarohalophile but not psychrothermobarophile Eutrophication- sudden introduction of large amounts of a previously limiting nutrient in an environment, leading to the Blooming of some organisms that may cause others to die off Microbe growth control o Sterilization- killing of all living cells o Disinfection- killing/removal of pathogens from inanimate objects- might not kill non-pathogenic microbes o Antisepsis- killing/removal of pathogens from living tissue o Sanitation- reducing microbial population to safe levels o Physical agents Heat- autoclave/high temp. moist heat more effective than dry Pasteurization- high temp/short time (HTST) vs. low temp/long time (LTLT) Filtration Irradiation UV light- surface sterilization Gamma rays- electron beams- used for food and heat sensitive objects o Chemical agents used when we cannot apply physical agents like for skin/countertops antibiotic ethanol iodine chlorine
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'