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72 terms

Micro Test 1 packet 4

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tetrads
cocci that divide in 2 planes - groups of 4
sarcinae
cocci divide in 3 planes - group of 8
.2-2. um diameter;
2-8 um length
prokaryote size
vibrios
curved rods; like comma
spirilla
have a distinctive helical shape like corkscrew, rigid bodies;
move by flagella
spirochetes
helical, flexible;
move by axial filament
Haloarcula
genus of square shaped cells
Stella
genus of star shaped cells
pleomorphic
have many shapes
Rhizobium;
Corynebacterium
ex of pleomorphic bacteria
glycocalyx/extracellular polymeric substances (EPS)
general term used to describe substances that surround bacterial cells - around cell wall;
gelatinous polymer of polysachharide, polypeptide or both
composition of glycocalyx
slime layer
if glycocalyx is unorganized and loosely attached to cell wall
capsule
if glycocalyx is organized and firmly attached to cell wall
virulence
degree to which a pathogen causes disease
virulence
capsules confer bacterial ___
phagocytosis and dehydration
capsules prevent
substrate attachment
capsules allow for
flagellum
long filamentous appendages that move bacteria
monotrichous
single polar flagellum
amphitrichous
single flagellum at both poles
lophotrichous
2 or more flagella at one or both poles of the cell
peritrichous
flagella distributed over the entire cell;
ex E. coli
Filamnet, hook, basal body
3 basic parts of flagellum
filament
long outermost region of flagellum which is constant in diameter and contains the globular protein flagellin;
not covered by membrane or sheath
flagellin
globular protein in prokaryote Flagellum
hook
structure to which the filament (of flagellum) is attached
basal body
anchors the flagellum to the cell wall and the plasma membrane;
-composed of central rod inserted into a series of rings
2 pairs
gram - have ___ # of rings
outer pair of rings in cell wall, inner pair of rings in plasma membrane
arrangement of basal body rings in gram - bacteria
only inner pair of rings in plasma membrane
arrangement of basal body rings in gram + bacteria
rotation of basal body
allows for movement of flagellum - either clockwise or counterclockwise
undulation
Eukaryotic flagella movement
run or swim
when a bacterium moves in one direction for a period of time
tumble
abrupt, random changes in direction caused by a reversal of flagellar rotation
taxis
movement of a bacterium towards or away from a perticular stimulus
phototaxis
stimulus is light
chemotaxis
stimulus is chemical
axial filaments/endoflagellum
bundles of fibrils that arise at the ends of the cell beneath the outer sheath and spiral around the cell;
Treponema pallidum
causative agent of syphilis
axial filaments
used for locomotion by spirochetes such as Treponema pallidum;
corkscrew motions
pili
hair-like appendages attached to bacterial cells-shorter than flagella
pilin
pili consist of this protein
pili
many gram - bacteria have this
common pili/fimbriae
allows a cell to adhere to surgaces
sex pili
join bacterial cells to allow transfer of DNA from one cell to another
conjugation
bacterial sex
cell wall
complex, semi rigid structure surrounding cell membrane
prevent rupture of bacterial cell;
maintain shape of bacterium;
point of anchorage for flagella;
produce symptoms of disease - some species
fx of cell wall
disaccharide + polypeptide
peptidoglycan
N-acetylglucosamine;
N-acetylmuramic acid
disaccharide of peptidoglycan composed of
NAM
tetrapeptide side chain attach to __
peptide cross bridge
parallel tetrapeptide side chains may be linked by a
alternating NAG and NAM
make up carbohydrate backbone of peptidoglycan
teichoic acid
consists of an alcohol (glycerlol) and phosphate; contained by gram + bact. ;
-have negative charge do to phosphate
regulate cation mvmnt in and out of cell;
pretent extensimve wall breakdown and cell lysis;
provide antigenic specificity
fx of teichoic acids
periplasmic space
gel-like fluid space where peptidoglycan layer resides in gram - bacteria
lipoprotein
peptidoglycan of g- interacts with __ in outer membrane
lipoproteins; lipopolysaccharides; phospholipids
outer membrane of g- bacteria consist of
lipid A (endotoxin)
is toxic in host blood, caused fever and shock - part of lipopolysaccharide
O polysaccharides
fx as antigens which can identify species of bacteria
phospholipids
part of outer membrane -strong neg charge held evade phagocytosis
porin proteins
proteins on outer membrane- non specific < 800 mw can enter
bacteriocin
proteins produced by some bacteria to kill closely related species
-attach to outer membrane proteins on specific channel proteins
Mycoplasma
have no cell walls- do have unique plasma membranes which contain sterols to protect cell from osmotic lysis - usually found in eukaryotes
lysozyme
catalyzes the hydrolysis of bonds between the NAG and NAM sugars of the peptidoglycan layers-destroying cell wall
protoplast
wall less gram + cell
spheroplast
gram - outer membrane and remaining cell
polymyxins
antibiotics that disrupt the phospholipids, thus destroying the cell wall
thylakoids
pigments and enzymes for photosynthesis are found in the ___ of plasma membrane
group transloctaion
like active transport but substance is chemically altered during transports;
-only in prokaryotes
bacteria plasma membrane
involved in ATP production;
contain enzymes which break down nutrients