Microbiology Chapter 1: Introduction to Microbiology Flashcards
AGENTS OF MICROBIOLOGY: EUKARYOTES (YOU) AND PROKARYOTES
PROKARYOTES(unicellular,lack nucleus): Bacteria, Archaea,
EUKARYOTES(unicellular or multicellular, distinct nucleus): Protists, Fungi, Helminths, Animal, Plants
WHAT IS THE GERM THEORY OF DISEASE?
-states that microbes cause infectious diseases
WHO PROPOSED THE GERM THEORY OF DISEASE?
WHO PROVED IT?
- Louis Pasteur proposed the germ theory of disease( hypothesized that air contains contaminating microbes)
- Robert Koch proved the germ theory of disease (Koch’s postulates)
KOCHS POSTULATES
- same organism must be present in every case of disease
- organism must be isolated from diseased host and grown as a pure culture
- isolated organism should cause same disease when inoculated into susceptible host
- organism must be re-isolated from the inoculated, diseased animal
PASTEUR’S EXPERIMENT DISPROVING SPONTANEOUS GENERATION
- used an S-necked flask partially filled with broth and boiled the broth(it remained unspoiled because microbes in air were trapped in the bent portion of the flask, unable to reach the liquid)
- when the flask was shaken broth encountered microbes trapped in the curved neck and spoiled
LEEWENHOEK
- refined earlier versions of the microscope (300x)
- first to see bacteria
REDI
- performed experiments to test the hypothesis of spontaneous generation ( meat in jars)
PASTEUR
- proposed germ theory of disease
- showed that biogenisis(life emerging from existing life) is responsible for propagation of life
- pasteurization of wine
- hypothesized that air contains contaminating microbes
- developed first vaccine against anthrax babies
KOCH
- proved the germ theory of disease
- developed staining techniques and media
- Koch’s Postulates
SEMMELWEIS(a.k.a SCRUB THEM HANDS BITCH)
- developed first aseptic techniques in the hospital setting
- recommended hand washing to decrease mortality rate from childbed fever
LISTER(lister=listerine=sterilizing)
- investigated processes of aseptic surgery
- proved sterilizing instruments and sanatizing wounds prevented pus formations
NIGHTINGALE=NURSING
- established aseptic techniques in nursing
- founder of modern nursing
HOOKE (a hooker for them scopes)
- built early microscopes
- first to publish description of cells
SNOW
- determined the cause of cholera transmission in London (contaminated water)
THE SCIENTIFIC METHOD
- observation
- hypothesis (tentative explanation of phenomena)
- experiment (tests a hypothesis)
- result (data collected from experiment)
- conclusion (supports or refutes hypothesis)
SCIENTIFIC LAW
SCIENTIFIC THEORY
SCIENTIFIC LAW: precise statement or mathematical formula that predicts a specific occurence
SCIENTIFIC THEORY: an explanation of natural phenomena based upon a preponderance of overwhelming scientific evidence
BRIGHT FIELD MICROSCOPY
- sample must be stained or have natural coloration
- illuminates species with cone of light
- bright background
- image formed based on how light is absorbed
DARK FIELD MICROSCOPY
- negative image
- sample appears light on a dark background
- image formed base on how light is scattered
- visualizes stained and unstained specimens (alive or dead)
PHASE CONTRAST MICROSCOPY
- negative image
- sample appears light on a dark background
- phase shifts that light experiences as it passes through a sample are converted into visible changes in brightness to provide richer shading and contrast
- visualizes unstained or stained specimens (dead or alive)
DIFFERENTIAL INTERFERENCE CONTRAST
- false 3D appearance
- illuminates species with polarized light
LIGHT MICROSCOPES
- use light waves
- color images possible
- provide a maximum of 1,000x
- resolution of 200 nm
- specimens can be living or dead
- stains often used/ can sometimes go without staining
ELECTRON MICROSCOPES
- use an electron beam
- only black and white images
- can magnify over 500,000x
- specimens are all dead
- specimens often must be stained with osmium or gold
SIMPLE STAINING
- use one dye
- size, shape, and cellular arrangement can be determined
- smear covered with methylene blue so dye can penetrate cells, then it is rinsed
- viewed with light microscope
- uses basic dyes mildly basic on the pH scale (positively charged)
STRUCTURAL STAINING
- flagella(motility) staining
- capsule( sticky carbohydrate based structures) staining
- bacterial endospore(dormant structures made in response to stressful or harsh conditions) staining
ACIDIC STAINING
- negatively charged
- stain background of a specimen
- do not easily enter cells
GRAM STAINING
- one of the most important stains in microbiology
- knowing gram property of a specimen has clinical implications including pathogenic features, what antibiotics might be most effective in combating it
- shows chemical and structural differences between cell walls
- gram positive bacteria remain purple/ gram negative bacteria are colorless
- gram positive bacterial cell walls contain peptidoglycan (protein carbohydrate substance) and do not have an outer membrane (negative do)
ACID-FAST STAINING
- distinguishes between cells with and without waxy cell walls
- acid fast bacteria have waxy cell walls that are rich in a substance called myolic acid that retain the red colored primary dye even after exposed to an acid wash/ non acid-fast cells color is stripped away
- detects myobacterium species
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TAXONOMIC HIERARCHY
Delightful- domain
King - kingdom
Philip- phylum
Came- class
Over- order
For- family
Great- genus
Spaghetti-species
BINOMIAL NOMENCLATURE
- two name system
- Genus is the first name (capitalized)
- Species is the second name (lowercase)
- scientific names are italicized
3 DOMAINS OF LIFE
BACTERIA- unicellular, prokaryotic organisms
ARCHAEA- some live in extreme environments
EUKARYA- unicellular & multicellular eukaryotic organisms
EUKARYOTIC KINGDOMS
- group of similar organisms that can sexually reproduce together
PROKARYOTIC KINGDOM
- share physical characteristics and have at least 70% DNA similarity
BIOFILMS
- sticky communities made up of a single or diverse microbial species
- cells that seed a biofilm make adhesion factors to help them attach to a target surface
- 60-80% of infectious diseases in humans are due to biofilm creating molecules
QUORUM SENSING
-the collective sensing and responding to changes within a bacterial community
ASEPTIC TECHNIQUE
- preventing the introduction of potentially dangerous microbes to a patient; it doesn’t mean that everything in the healthcare setting needs to be sterile (absent of all microbes)
CULTURE MEDIA
CULTURE MEDIA- mixtures of nutrients that support organismal growth in an artifical setting
- agar
- nutrient broth
INTERSPECIFIC AND INTRASPECIFIC COMMUNICATION
INTERSPECIFIC: communication between different species of animals, plants, or microorganisms
INTRASPECIFIC: occurs between members of the same species.
