Module 1 & 2 Flashcards
Microbiology definition
The study of very small things
Microorganisms
germs or microbes
Living organisms too small to be seen with the naked eye
Microorganism groups
Bacteria
Fungi (yeast or mold)
Protozoans
Microscopic algae
viruses
Positive roles of microbes
Form basis of food chains in oceans, lakes, and rivers
Break down wastes
photosynthesis
digestion and synthesis of vitamin k and vitamin b
food production
Opportunistic pathogen
Non-pathogenic becomes pathogenic when the conditions are right
(c. diff)
Robert Hooke
First microscope
Created cell theory (all living things are composed of cells)
Edward Jenner
First mandatory vaccine
Found small pox vaccine by using cow-scrapings
pasteurization versus sterilization
pasteurization involves food while sterilization involves inanimate objects
Theory of spontaneous generation
False idea stating that life can come from non-living materials
Joseph Lister
Applied germ theory to medical procedures (hand washing)
Discovered first disinfectant (phenol) which served as a hand sanitizer
Louis Pasteur
Theorized germs caused disease
disproved the theory of spontaneous generation
demonstrated microbial life can be destroyed by heat and methods can be designed to block the access of airborne microoganisms to nutrient environments
formed the basis of aseptic techniques
discovered pasteruization
Found out why vaccines worked (but not boosters)
used live attenuated or weakened pathogen
Robert Koch
First proof that bacteria causes disease by injecting cows (Koch’s postulate)
Koch and Petri developed the petri dish
Arthur Flemming
Penicillin
Antibiotic problems
Damaging side effects to host
antibiotic-resistant microorganism
Wendell Stanley
Discovered tobacco mosaic virus (first virus discovered)
cannot be filtered out
Notable microorganisms
Legionella pneumophilia
Staphylococcus aureus
HIV
Yersinia pestis
Flesh eating streptococcus
SARS virus
h1N1 influenza virus
Ebola
Covid 19
How to write a microorganism name
Genus (first, capitalized, italicized)
species (follows, not capitalized, italicized)
Who devised the five-system classification system?
Robert Whitaker
What is the size of most bacteria?
0.20-2.0 microns in diameter and 2-8 microns in length
How do cocci divide
binary fission
diplococci
pairs
streptococci
chainlike
tetrads
groups of 4
sarcinae
cubelike, 8
staphylococci
grapelike clusters
cocci
spherical
bacilli
rod-shaped
how do bacilli divide
only across their short axis
diplobacilli
pairs
streptobaccili
chains
coccobacilli
oval, in between bacilli and cocci
spirochetes
spiral
vibrio
commas
spirilla
helical shape, like a corkscrew. has flagella
spirochetes
no flagella, move by axial filament
Stella
star shaped cell
Arcula
square shapes, flat cells
what can affect shape
antibiotics and environment
what are cell walls made up of
peptidoglycan
what determines the virulence factor
glycocalyx (how well it sticks)
capsule slime layer
Glycocalyx
external to cell membrane
can take the form of a capsule or slime layer, flagella, axial filaments, and pili
gelatinous polymer (protection) composed of polypeptides, polysaccharide or both
viscous (sticky)
made inside the cell and excreted outside
protects against dehydration and inhibits the movement of nutrients from the cell
Called a capsule if
causes virulence in an organism
virulence
degree to which bacteria causes disease
called a slime layer when
purpose is to attach a bacterium to various surfaces in order to survive
Flagella
Long filamentous appendages that propel bacteria
Move in a helical rotary fashion
Four arrangements
monotrichous
single polar flagellum
amphitricious
single flagella at both ends of the cell
lophotrichous
two or more flagella at one or both ends of the cell
peritrichous
flagella distributed over the entire cell
Axial filaments
Facilitate the movement of spirochetes
Bundles of fibrils that spiral around the cell
Rotation of filaments causes the rigid helical cell to rotate in the opposite direction and move as a corkscrew
Pili
Hair like appendages, shorter and thinner than flagella
Can occur at the poles or over the entire surface
many gram-negative bacteria have pili
two types of pili
Common pili
allow cell to adhere to surfaces
including the surface of other cells
Neisseria gonorrhea is an example
Sex pili
Functions to join bacterial cells prior to the transfer of DNA
Cell wall
Semi-rigid structure responsible for the shape
almost all prokaryotes have it
composed of peptidoglycan
Cell wall function
prevent cell rupture from osmotic pressure
maintain the shape
anchors the flagella
produce symptoms of disease in some
site of action of some antibiotics
Gram positive bacteria
Has thick layers of peptidoglycan
cell walls contain teichoic acid (makes it possible to be identified serologically, like strep)
Teichoic acid helps to prevent cell wall lysis
Acid fast bacteria (mycobacterium)
consists of peptidoglycan and 60% lipids
gram negative bacteria
contain peptidoglycan in small amounts
have no teichoic acids
peptidoglycan layer surrounded by an outer membrane of lipopolysaccharides (LPS), lipoproteins, and phospholipids
increased permeabiltiy of the cell wall
Gram negative bacteria outside layer function
strong negative charge helps to evade phagocytosis and the action of complement
provides a barrier to certain substances (penicillin) and is permeable to others
What two characteristics of gram negative bacteria does LPS provide
O polysaccharides that function as antigens in serological testing.
Lipid A is an endotoxin that can be toxic in hosts blood stream
Atypical cell walls
prokaryotes that naturally have no walls or have very little wall material
cannot be plated
Atypical cell wall species
Mycoplasma and ureaplasma
Plasma membrane
selectively permeable
breaks down nutrients and helps produce energy
Mesosomes
Mesosomes
Irregular folds of the plasma membrane
function is unknown
thought to play a role in reproduction and metabolism
