study questions for test 1 Flashcards
explain the spontaneous and biogenesis hypotheses
spontaneous generation: belief that invisible vital forces present in matter led to the creation of life
biogenesis hypotheses: living things arise only from others of their same kind
know all the scientists and their contributions
Robert Hooke: discovered the first “non-living” cells
Antony van Leeuwenhoek: discovered the first “living” cells
Edward Jenner: developed vaccine for smallpox, established role of microorganisms in disease
Rudolf Virchow: developed Cell Theory: said cells arise from preexisting cells
Ignaz Semmelweis: described importance of handwashing; prevents disease in the hospital setting
Louis Pasteur: pasteurization; swan-necked flasks; vaccines; disproves spontaneous generation; conducted the 1st studies linking human disease to infection
Joseph Lister: used aseptic techniques in surgery
Robert Koch: Germ Theory of Disease
what are koch’s postulates
give ex of when these 4 postulates do NOT apply
Koch’s postulates are a series of logical steps that establish whether or not an organism is pathogenic and which disease it causes aka Germ Theory of Disease
- microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms
- Microorganisms must be isolated from a disease organism and grown in pure culture
- cultured microorganisms should cause disease when introduced into a healthy organism
- Microorganisms must be reisolated from the inoculated diseased experimental host and identified as being identical to the og specific causative agent
ex. if no animal model for the organism, cannot ethically do this (cannot infect people)
list types of microscopy and an ex of what each is used for
Brightfield: stained bacteria
Darkfield: live bacteria that moves like corkscrews
Phase Contrast: intracellular structures of endospores, granules, organelles, cilia
TEM: detailed intracellular structure of cells and viruses
SEM: detailed extracellular structure of cells and viruses
Fluorescence: diagnosis infections and pinpoints particular cellular structures
ex of all stains in ch 2 and ex of what each is used for
positive stain: dye sticks to the specimen and gives it color
negative stain: does not stick to the specimen but settles some distance from its outer boundary
simple stains: one dye; reveal shape, size, arrangement; ex: crystal violet stain of e coli
differential stains: primary dye and counterstain; distinguish cell types or parts; ex: gram stain
special stain: used to emphasize cell parts that are not revealed by conventional staining methods; ex: flagellar stain of proteus vulgaris
name the 3 domains and the general classification levels from domain to species
3 domains: Eukarya, Bacteria, Archaea
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
ex of how microbes interact with us in our everyday lives
production of bread, alcohol, cheese etc.
characteristics of eukaryotic vs bacteria cells
Eukaryotic cells: animals, plants, fungi, protozoa; contain organelles that are encased by membranes and perform specific functions
Bacteria cells: no nucleus or other organelles; complex fine structure; can engage in same activities as eukaryotic cells
macromolecules and their functions
carbohydrates: body’s primary source of energy
lipids: moving and storing energy, absorbing vitamins and making hormones
proteins: help repair and build body’s tissues; allow metabolic reactions to take place and coordinated bodily functions
nucleic acids: carry genetic info
complex vs chemically defined
selective vs differential vs general purpose media
complex defined: one or more compounds is not chemically defined; contains extracts of animals, plants, yeasts
chemically defined: contain pure organic and inorganic compounds that vary little from one source to another
general purpose media: grow as broad a spectrum of microbes as possible
selective media: contains 1 or more agents that inhibit the growth of a certain microbe(s); important in isolation of a specific type of organism
differential media: allow multiple types of organisms to grow but display visible differences in how they grow; variation in colony size or color; media color changes; gas bubbles
premise and purpose of streak for isolation technique
the purpose is to get a colony
an individual bacterial cell is separated from other cells on a nutrient surface
resolution
total magnification
resolution: capacity of an optical system to distinguish 2 adjacent objects or points from one another
total magnification: power of objective x power of ocular
bacteria arrangement
cocci: diplococci pairs; streptococci chains; staphylococci irregular clusters
bacilli: diplobacilli pair of cells with ends attached; streptobacilli chain
bacteria morphology (shapes)
coccus: spherical, ball shaped
bacillus: rod shaped
vibrio: comma shaped
spirillum: spiral shaped body
spirochete: spiral cells with periplasmic flagella
filaments: branches
parts of flagella
purpose of each part
arrangement of flagella
filament: tail-like projection
hook: connects filament to the basal body
basal body: the motor
monotrichous: single flagellum
lophotrichous: small bunches of flagella emerging from the same site
amphitrichous: flagella at both poles of the cell
peritrichous: flagella are dispersed randomly over the surface of the cell
structures and purpose:
fimbriae
pilus
s layer
glycocalyx (slime layer and capsule)
cell wall
fimbriae: small bristle like fibers sprouting off the surface of many bacterial cells; allow tight adhesion between fimbriae and and epithelial cells, allowing bacteria to colonize and infect host tissues
pilus: used in conjugation between bacterial cells; gram - bacteria; type IV pilus can transfer genetic material act like fimbriae and assist in attachment and act like flagella and make bacterium motile
s layer: single layer of thousands of copies of a single protein linked together like tiny chain like fences; only produced when bacteria are in a hostile environment
glycocalyx: coating of repeating polysaccharide or glycoprotein units
slime layer: loose protects agaisnt loss of water and nutrients
capsule: more tightly bound denser and thicker; produce a sticky (mucoid) character to colonies on agar
cell wall: helps determine the shape; provides strong structural support to keep bacteria from bursting or collapsing because of osmotic pressure; gains relative rigidity from peptidoglycan
describe cell wall of gram - and gram + and the molecules they contain
gram + cell wall: thick sheet of peptidoglycan; contains teichoic acid & lipoteichoic acid: function in cell wall maintenance and enlargement, contribute to the acidic charge on cell surface
gram - cell wall: thin sheet of peptidoglycan; thinness gives gram - cells more susceptibilty to lysis; contains lipopolysaccharide and porin proteins
lipopolysaccharide is made up of O polysaccharide (used to differentiate strains of the same species), Core polysaccharide (stabilizes molecule), & Lipid A ( sensitive aspect, toxic to humans, endotoxin)
porin proteins: special membrane channels that only the outer membrane allows certain chemical to penetrate
basic function of peptidoglycan and how its structured
provides a strong but flexible support framwork
repeating framework of long glycan (sugar) chains cross-linked by short peptide (protein) fragments
NAG and NAM
describe
acid fast bacteria
mycoplasma
acid fast bacteria: contain mycolic acid: found in cell walls, makes bacteria highly resistant to certain chemicals and dyes ex. mycobacterium
mycoplasmas: naturally lack a cell wall; sterold in the cell membrane stabilize the cell against lysis ex. mycoplasma pneumoniae
describe prokaryotic plasma membrane and its purpose
contains:
peripheral proteins: loosely associated with the membrane, easily removed; play a role in enzymatic reactions
integral proteins: embedded within the membrane, not easily removed; structural components for transport/secretion and respiration
hopanoids: embedded within the membrane; steroid-like chains that provide a flexible but rigid framework for the membrane
purpose: selectively permeable barrier that regulates the passage of materials into and out of the cell
describe
cytoplasm
chromosomes
plasmids
ribosomes
specified inclusion bodies
endospore
Cytoplasm: 70-80% of water; complex mix of sugars amino acids and salts
Chromosomes: hereditary material exists in here
Plasmids: nonessential piece of DNA; confer protective traits such as drug resistance and toxin and enzyme production
Ribosomes: site of protein synthesis
Specified inclusion bodies: storage “unit”; stores energy, food, gas, etc.
Endospores: made when bacteria is trying to survive; can resist extreme temp and environments
basic components of a virus
genome: DNA or RNA
capsid: protein coat
nucleocapsid: capsid and genome
capsomeres: capsid is made of individual proteins
basic morphologies of viral capsids
icosahedral capsid symmetry: contain spikes
helical capsid symmetry: circle
what is a viral species
a group of viruses sharing the same genetic info and ecological niche (host)
