Shah Chapter 4 Flashcards
Used to view external structure
Light microscope
Used to view internal structures
electron microscope
Isolation of cell components; fractionation
causing cell to break apart
Isolation of cell components; ultracentrifugation
Spinning the cell to separate parts by weight
Spherical or round
coccus; cocci
rod shaped
bacillus; bacilli
Helical, flexible, corkscrew, can swim by rotation or creeping, have 2-100 periplasmic flagella
spirochete
Helical, rigid, loose S, can be in tufts, swim by rotating around like corkscrews
spirillum, spirilla
Comma shaped
vibrio
cocci, diplococci, streptococci, staphylococci
singles, in pairs, chains, irregular clusters
Bacilli, diplobacilli, streptobacilli
singles, in pairs, chains
Pleomorphism
occurence of more than one shape in its life e.g Mycoplasma lacks cell wall causing it to easily change shape
How does glycocalyx make a bacterium more virulent
prevents dehydration, gives protection from antibiotics
bacterial cell wall of domain bacteria composed of a complex of proteins and carbohydrates arranged in a lattice pattern this substance is called
peptidoglycan
prokaryotic structure that is composed of the protein pilin and functions in conjugation also known as horizontal gene transfer (sex bridge)
Pili
Motility
Flagella & Axial filaments
Attachment or channels
fimbriae and pili; to obtain nutrients
Monotrichous
single flagellum at one end
Lophotrichous
small bunches (tufts) emerging from the same site
Amphitrichous
flagella at both ends of the cell
peritrichous
flagella dispersed over surface of cell
genus of bacteria that have a cell wall composed of peptidoglycan covered with a layer of wax
myobacterium
Chemical Stimuli (chemotaxis) guides bacteria in a direction
positive(towards) negative(away)
flagella in counterclockwise results in
smooth linear direction
flagella in clockwise results in
tumbles
A small circular extra chromosomal piece of DNA that may contain genes for toxin production or antibiotic resistance
Plasmid
non-living crystal- like granules within the prokaryotic cytoplasm that may be permanent or transient but seem to function as reserve deposits (storage of molecules)
Inclusion
In a negative stain does the capsule take the stain?
NO
In a simple acidic stain (the color is in the negative ion & is repelled by negative cell wall) colors what?
The background
A bacterium that has thick peptidoglycan and a small amount of techie acid its cell wall would be what color after completion of the Gram Stain?
Purple
Color of gram negative cells after completion of the decolorizing step during the gram stain procedure
Clear
Stressful conditions such as the depletion of nutrients from the environment can cause some gram positive bacilli to form a protective structure known as a
Endospore
Gram-positive cell wall
thick cell wall, 20-80nm composed primarily of peptidoglycan, includes teichoic acid and lipoteichoic acid, more penetrable, retain crystal violet and stain purple
Gram-negative cell wall
outer cell membrane, thin peptidoglycan layer 8-11nm, outer membrane contains lipopolysaccharides, lipid portion (endotoxin) may become toxic when released during infections, may function as receptors and blocking immune response, less penetrable, lose crystal violet and stain red/pink from safranin counterstain
exotoxins
specific to a cell type(blood, liver, nerve), stimulate antitoxins, tetanus, cholera, anthrax: gram pos and neg
endotoxins
Systemic: fever, inflammation, weakness, shock, does not stimulate antitoxins, Meningitis, endotoxic shock, salmonellosis: all gram neg bacteria
