• Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

Card Range To Study

through

image

Play button

image

Play button

image

Progress

1/47

Click to flip

Use LEFT and RIGHT arrow keys to navigate between flashcards;

Use UP and DOWN arrow keys to flip the card;

H to show hint;

A reads text to speech;

47 Cards in this Set

  • Front
  • Back
What is Microbiology?
The study of microorganisms, how they work, interact with the evironment, and interact with us.
Microbiology has it’s root in the study of bacteria, the largest and most important group of microorganisms.
From a cellular perspective, you might think the human body is mostly human. But you’d be wrong. It is actually mostly bacterial. The typical adult body is composed of about 100 trillion (10^14) cells. It harbors 1-2 x 10^15 bacterial cells from at least 500 species-about 20 times the number of human cells
Total number of microbial cells on Earth is about 5 x 10^30
The total amount of carbon present in this population equals that of all plants on earth.
The total amount of nitrogen and phosphorous present in prokaryotes is over 10 times that of all plant biomass.
Most prokaryotic cells reside underground in oceanic and terrestrial subsurfaces.
Are Microoorganisms friends or foes?
(Both!!!)
As we understand how microbes work, we can devise ways to increase their benefits and decrease their harmful effects.
What would be different about your life is all microorganisms ceased to exist?
“The role of the infinitely small in nature is infinitely large.” -Louis Pasteur
NO PIZZA!!!! NO NITROGEN FIXING!!!!
What are some of the different types (categories) of microbes?
Carolus Linnaeus developed system for naming plants and animals and grouping similar organisms together (taxonomic system)
Cellular microorganisms grouped into five categories:
Fungi
Protozoa
Algae
Prokaryotes (bacteria)
Small animals (helminths)
How are Dentistry and Microbiology Interwoven?
Caries and periodontal disease are the most costly diseases that the majority of the US population has to deal with during their lifetime
Lost productivity and treatment casts due to these conditions were estimated to exceed $81 billion in 2006.
New diseases will continue to emerge and infection control will always be with us.
What are the relative sizes and degrees of complexity of microbes?
A: Degrees of complexity
Viruses->Bacteria->Protozoa
Multicellular: Fungi and Algae
B: Relative Sizes
Viruses->Bacteria->Protozoa->Fungi,algae
What are Whittaker's 5 kingdoms?
Whittaker’s 5 Kingdoms:
Animilia, Fungi, Plantae, Protista (Protozoa), and Monera (Bacteria).
Woese’s 3 Domains
Bacteria (Eubacteria), Archaea (Archaebacteria), Eucarya
There is a large Microbial Umbrella which has Eucaryotic, Algae, Viruses, Procaryotic, Prions, Protozoa, Bacteria, etc....
What are Fungi?
Fungi
Eukaryotic (have membrane-bound nucleus)
Obtain food from other organisms
Possess cell walls composed of chitin
Composed of:
Molds-multicellular; have hyphae; reproduce by sexual and asexual spores
Yeasts-unicellular; reproduce asexually by budding; some produce sexual spores.
Diseases:
Ringworm
-Yeast infections (Candidiases)
-Coccidioidomycosis
-Histoplasmosis
-Cryptococcosis
-Pneumocystis pneumonia
Example of Fungi: Penicillium chrysogenum--a mold.
Examples of Fungi: Saccharomyces cerevisiae, a yeast. Has budding cells.
What are Protozoa?
Protozoa
Single-celled eukaryotes
Similar to animals in their nutritional needs and cellular structure
Typically live freely in water; some live inside animal hosts
Most reproduce asexually; some reproduce sexually
Most are capable of locomotion by:
-Pseudopodia-cell extensions that flow in direction of travel
-Cilia-numerous, short, hair-like protrusioins that propel organisms through environment
-Flagella- extensions of a cell that are fewer, longer, and more whip-like than cilia.
Examples of Protozoa: Amoeba Entamodba histolytica causes amebic dysentery
Balantidium coli causes diarrhea and dysentery.
Trypanosoma brucei causes African Sleeping sickness
Other diseases caused by flagellates:
-Chagas’ diseas
-Baghdad boil (Leishmania)
-Giardiasis
Non-motile protozoa which cause diseases:
-Plasmodium (malaria)
-Toxoplasma
-Cryptosporidium
What are Algae?
Algae
Unicellular or multicellular
Photosynthetic
Simple reproductive structures
Categorized on the basis of pigmentation, storage products, and composition of cell wall
Non-pathogenic except for their role in red tides and shellfish poisoning
Examples of Algae:
Spirogyra sp.
Diatoms
What are Prokaryotes
Unicellular and lack nuclei
Much small than eukaryotes
Found everywhere there is sufficient moisture; some found in extreme environments (Archaea)
Reproduce asexually
Two kinds
Bacteria-cell walls contain peptidoglycan; som lack cell walls; most do not cause disease and some are beneficial.
-Archaea- cell walls composed of polymers other than peptidoglycan; no diseases
Examples of Prokaryotes:
Streptococcus sp.
What are other Organisms of Importance to Microbiologists?
Wuchereria in blood (Elephantiatis)
***EVERYTHING IS PARASITIZED BY VIRUSES****
Types of Helminths:
Cestodes=Tapeworms (Taenia)
Tematodes=Flukes (Schistosoma
Nematodes = Roundworms (Ascaris)
T2 Bacteriophage
Give an example of each of the important microorganisms we discussed?
Fungi: Dermatophytoses
Protozoa: Malaria, amebiases
Algae: Shellfish poisoning
Prokaryotes (bacteria) TB, diphtheria
Helminths (worms) macroscopic Tapeworms, flukes, and roundworms)
Viruses (sub light microscopic) AIDS, influenza, West Nile, SARS
What are the General Principles of Microscopy?
General Principles of Microscopy
Wavelength of Radiation: visible light has an average wavelength of 550 nm
Magnification: Use of lenses to increase the apparent size of the object
Resolution: = resolving power = closest you can get 2 objects adn still see them as separate = .61 ^/NA; NA= numerical aperture = ability of lens to gather light = n sin 0; The smaller the distance, the better the resolution. Resolving power of; eye=.3mm; light microscope=.2um; e-microscope=.2nm
Contrast: Differences in intensity of an object and it’s background. Staining is used to increase this contrast.
What is the Electromagnetic Spectrum?
400nm blue, red is 750nm. That is visible light.
The spectrum goes from
Gamma rays, X-rays, UV light, Visible light, Infared, Microwave, Radio waves and Television.
What is Empty Magnification?
Empty Magnification= beyond maximum, you can’t see anything
What is a Compound Microscope?
Compound
-Uses a series of lenses for magnification
-Light rays pass through a specimen and into objective lens (one of a series)
-Oil immersion lens increases resolution because light does not refract
-Has one or two ocular lenses
-Total magnification = magnification of objective lens X magnification of ocular lens.
-Most have condenser lens to direct light through specimen.
What is the Effect of Immersion Oil?
The higher the objective power, the shorter the working distance, and the greater the need for immersion oil.
What is light Microscopy's typical objective lenses adn their numerical aperatures?
Typical objective lenses and their numerical apertures (NA):
Magnification NA
10x .30
40x .75
100x 1.30
RP =.61 ^/NA
=.61 450 nm/1.3
=211 nm
What are Phase Microscopes?
Used to examine living organisms or specimens that would be damaged or altered by attaching them to slides or staining them
These microscopes treat one set of light rays differently from another set
Light rays in phase produce brighter image, while light rays out of phase produce darker image
Contrast is created because light waves are ½ wavelength out of phase
Two Types:
-Phase-Contrast Microscope
-Differential Interference Contrast (DIC) Microscope
What are Dark-Field Microscopes?
Best for observing pale or very thin objects that are living
Dark-field stop in the condenser prevents direct light rays from reaching the speciment; only oblique rays illuminate
Only those oblique light rays scattered by specimen enter objective lens
Specimen appears light against dark background
Increases contrast and enables observation of thin and translucent orgs.
What are Fluorescent Microscopes?
Direct UV light source at specimen; flurorochromes absorb teh UV light and radiate energy back as a longer, visible wavelength.
UV light increases resolution and contrast
Some cells and molecules are naturally fluorescent, while others must be stained
Used in immunofluorescence to identify pathogens and to locate and make visible a variety of cellular proteins.
What is Electron Microscopy?
Light microscopes cannot resolve structures closer than 200 nm because shortest wavelength of visible light is about 400 nm
Electrons have wavelengths of 0.01 nm to 0.001 nm, so electron microscopes have greater resolving power and greater useful magnification is possible.
Magnify objects 10,000X to 100,000X
Provide detailed views of bacteria, viruses, internal cellular structures, molecules, and large atoms.
Two types
-Transmission electron microscopes (TEM)
-Scanning electron microscopes (SEM)
What are the purposes of heat fixing?
Purposes of Heat-Fixing:
Fix the organisms to the slide
Kill the organisms
What does staining do?
Increases contrast and resolution by coloring specimens with stains/dyes
Smear of microorganisms (thin film) air dried to slide and then fixed to surface by heat or chemicals (also killed)
Microbiological stains are usually salts composed of cation and anion and one is colores (chromophore)
Acidic dyes stain alkaline structures; basic dyes stain acidic structures (negatively charged) and are used more commonly on microorganisms
What are the different types of stains?
Simple Stains
Differential Stains
-Gram Stain
-Acid-Fast Stain (Acid Fast Organisms will be red, the rest will be blue)
-Endospore Stain
Special Stains
-Negative (Capsule) Stain
-Flagellar Stain
-Fluorescent Stains
Staining for Electron Microscopy
What are the external structures of Prokaryotic Cells
Glycocalyces
Flagella
Fimbriae and Pilli
What are Glycocalyces?
Gelatinous, sticky substance surrounding the outside of the cell
Composed of polysaccharides, or rarely, polypeptides, or both
Two types:
Capsule
Slime Layer
What is the Capsule?
Composed of organized repeating units of organic chemicals.
Firmly attached to cell surface
Protects cells from drying out
May prevent bacteria from being recognized and destroyed by host
What is the Slime Layer?
Loosely attached to cell surface
Water soluble
Protects cells from drying out
Sticky layer that allows prokaryotes to attach to surfaces
What are Flagella?
Responsible for movement
Long, propeller-like structures that extend beyond surface of cell
For prokaryotes, these are rigid, protein helices that rotate
What is the structure of the Flagella?
Composed of filament, hook, and basal body
Flagellin protein (filament) arranged in chains and forms helix around hollow core
Base of filament inserts into hook
Basal body anchors filament and hook to cell wall by a rod and a series of either two or four rings
Filament capable of rotating 360 degrees
What is the function of flagella?
Rotation propels bacterium through environment
Rotation can be clockwise or counterclockwise; reversible
Prokaryotes move in response to stimuli (taxis). For cells with multiple flagella:
-Runs: movements of cell in single direction for some time; increase with favorable stimuli (positive chemotaxis, positive phototaxis)
-Tumbles: abrupt, random, changes in direction; increase with unfavorable stimuli (negative chemotaxis, negative phototaxis)
What are Fimbriae and Pili?
Nonmotile extensions
Fimbriae
Sticky, proteinaceous, bristlelike projections
Used by bacteria to adhere to one another, to hosts, and to substances in environment
May be hundreds per cell and are shorter than flagella
Serve an important function in bioflims.

Pili
Long hollow tubules composed of pilin
Longer than fimbriae but shorter than flagella
Bacteria typically only have one or two per cell; function as grappling hooks
Join two bacterial cells and mediate the transfer of DNA from one cell to another (conjugation)
Also known as conjugation pili or sex pili
Explain Prokaryotic Cell Walls.
Provides structure and shape and protects cell from osmotic forces
Assists some cells in attaching to each other
Can function as a barrier to certain antimicrobial substances
Animal cells have no cell walls; can target cell wall of bacteria with antibiotics
Bacteria and archaea have different cell wall structure and chemistry.
Explain Bacterial Cell Walls
Most bacteria have cell walls composed of peptidoglycan; a few lack a cell wall entirely (i.e. Mycoplasma)
Peptidoglycan composed of sugars, NAG and NAM
NAG-NAM polymers are connected by tetrapeptide crossbridges
-Bridges may be directly linked to one another, or
-Bridges may be joined by short connecting chains of amino acids
3 basic types of bacterial cell walls.
What are Gram-Positive Cell Walls?
-Relatively thick layer of peptidoglycan
-Contains unique polysaccharides called teichoic acids (-phos-ribitol-)n
Some covalently linked to lipids, forming lipoteichoic acids that anchor peptidoglycan to cell membrane
Retains crystal violet dye in Gram staining procedure; appear purple
What are Gram-Negative Cell Walls?
2. Gram-Negative Cell Walls
Have only a thin layer of peptidoglycan
Have an outer bilayer membrane composed of phospholipids, channel proteins (porins), and lipopolysaccharide (LPS)
LPS is called endotoxin and is toxic to animals
Following Gram staining procedure, cells appear pink
What is Gram-negative LPS?
Gram-negative Lipopolysaccharide (LPS)
KDO=ketodeoxyoctonate
Hep=Heptose
Glu=Glucose
Gal=Galactose
GluNac=N-acetylglucosamine
GlcN=Glucosamine
P=Phosphate
What is LPS?
Lipopolysaccharide (LPS)
Union of lipid with sugar
Also known as endotoxin
Lipid portion known as lipid A
Released from dead cells when cell wall disintegrates
Can trigger fever, vasodilation, inflammation, shock, and blood clotting
Often released when antimicrobial drugs kill
What are Acid Fast Cell Walls? Structure?
3. Acid Fast Cell Walls
Contain layers of wax-like lipid
Up to 60% of cell wall can by mycolic acids

Structure of an Acid-Fast Cell Wall
Proteins, free lipids, glycolipids, and peptidoglycolipids
Arabinogalactan=D-arabinose and D-galactose
PIM=phosphatidyl-inositol mannosides
What is Periplasmic Space?
Between outer membrane and plasma membrane
Contains water, nutrients, and substances secreted by teh cell, such as digestive enzymes and proteins involved in transport and signal transduction
What are Archael Cell Walls?
Do not have peptidoglycan
Cell walls contain variety of specialized polysaccharides and proteins
Gram-positive archaea stain purple
Gram-negative archaea stain pink
Archea Cell Walls
Pseudopeptidoglycan contains N-acetylalosaminuronic acid (NAT) instead of NAM
What are the components of Cytoplasm of Prokaryotes?
Cytoplasm of Prokaryotes
Cytosol-liquid portion of cytoplasm
Inclusions- may include reserve deopsits of chemicals
Ribosomes- involved in protein synthesis
Cytoskeleton -plays a role in forming the cell’s basic shape
What can the granules in bacteria be composed of?
Inclusion Granules in Bacteria
Could also be composed of:
1. Glycogen
2. Phosphate
3. Sulfur
4. Gas
How do prokaryotic cells reproduce?
Reproduction of Prokaryotic Cells
All reproduce asexually
Basic methods:
-Binary fission (most common)

Endospores
Produced by Gram-positive rods: Bacillus and Clostridum
Each vegetative cell transforms into one endospore
Each endospore germinates to form one vegetative cells
Constitute a defensive strategy against hostile or unfavorable conditions; not a reproduction mechanism

Endospores
Extremely resistant to drying, heat, radiation, and lethal chemicals
Stable resting stages
Can remain viable for tens to thousands of years
Serious concern to food processors, health care professionals, and governments.
What did Linnaeus do?
Linnaeus provided system that standardized the naming and classification fo organisms based on characteristics they have in common.
Grouped similar organisms that can successfully interbreed into categories called species
Binomial Nomenclature
What are some of the Taxonomic and Identifying characteristics of microorganisms?
Physical Characteristics
Morphology and staing
Biochemical Tests
O2 requirements and enzymes
Serological Tests
Phage Typing
Analysis of Nucleic Acids