Ch 4 Book Flashcards
structurally how are prokaryotes different from eukaryotes
they are simpler and smaller
genetic material is not surrounded by a membrane
lack membrane enclosed organelles
how are prokaryotes and eukaryotes similar
both contain nucleic acids, proteins, lipids, ad carbohydrates
describe the DNA in prokaryotes
not enclosed within a membrane and is usually a singular circularly arranged chromosome
not associated with histones
what do the cell wall of prokaryotes have
polysaccharide peptidoglycan
how do prokaryotes divide
by binary fission(DNA is copied and cell splits into two cells)
what do prokaryotes include
bacteria and archeae
what are the types of bacteria
cocci, bacilli, spiral
if remain in pairs after dividing, round
diplococci
if remain in chainlike pattern after dividing, round
streptococci
if remain attached in cubelike groups of 8
sarcinae
form grapelike clusters/broad sheets
staphylococci
fewer groupings of these than of cocci
bacilli
pairs after division, rodlike
diplobacilli
occur in chains, rodlike
streptobacilli
oval and look like cocci
coccobacilli
have one or more twists
spiral
look like curved rods
vibrios
helical shape/corckscrew
spirilla
helical and flexible
spirochetes
what is the shape of bacteria determined by
heredity
most bacteria, maintain single shape
monomorphic
bacteria that can have many shapes
pleomorphic
this is the sugar coat and is the substance that surrounds cells
glycocalyx
what is the glycocalyx composed of
sticky polymer composed of polysaccharide or polypeptide
if the substance is organized and is firmly attached to the cell wall
capsule
if the substance is unorganized and only loosely attached to the cell wall
slime layer
these protect pathogenic bacteria from phagocytosis by the cells of the host
capsules
this is an important component of biofilms
glycocalyx
a glycocalyx that helps cell in a biofilm attach to their target environment and eachother(protects the cells within it)
extracellular polymeric substance (EPS)
what does the glycocalyx also do
protect a cell against dehydration and its viscosity may inhibit the movement of nutrients out of the cell
long filamentious appendages that propel bacteria
flagella
bacteria that lack flagella
atrichous
flagella that are distributed over the entire cell
peritrichous
flagella at both ends of the cell
polar
single flagellum at one pole
monotrichous
tuft of flagella at one pole
lophotrichous
flagella at both poles
amphitrichous
what are the three basic parts of the flagella
filament, hook, basal body
this is the outermost region of flagella, contains flagellin
filament
this is attached to filament of flagella, slightly wider, different protein
hook
this anchors the flagellum to the cell wall and plasma membrane
composed of rod inserted rings
basal body
these types of cell contain two pairs of rings in the basal body of flagella
gram negative
these types of cells contain one inner pair of rings in the basal body of flagella
gram positive
ability of an organism to move by itself
motility
what does motility enable the bacterium to do
move toward a favorable environment or away from an adverse one
this is the movement of a bacterium towards or away from a particular stimulus
taxis
what are the two types of taxis
chemotaxis and phototaxis
what is useful for distinguishing among serovars
H antigen
these are variations within a species of gram negative bacteria
serovars
AKA endoflagella
bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell
axial filaments
these are hairlike appendages that consist of pilin
fimbriae and pili
this is involved in forming biofilms and other aggregations on the surfaces of liquids
fimbriae
these help bacteria adhere to epithelial surfaces and are primarily used for attachment
fimbriae
how many fimbriae are usually found per cell
range from several to a couple hundred
this is longer than fimbriae and only has two per cell
pili
what are pili involved in
motility and DNA transfer
pilus extends by the addition of subunits of pilin, makes contact with another cell and then retracts
twitching motility
smooth gliding movement of myxobacteria
provides a means for microbes to travel in environments with a low water content
gliding motility
transfer DNA from one cell to another
conjugation (sex) pili
this protects the interior of the cell from adverse changes in the outside environment; all prokaryotes have this!
cell wall
what is the function of cell walls
Prevent bacterial cells from rupturing when the water pressure inside the cell is > than that outside the cell
Maintains the shape of the bacterium and anchorage point for flagella
when does the cell wall extend
as the volume of the cell increases
what are bacterial cell walls composed of??
PEPTIDOGLYCAN
what does peptidoglycan consist of
repeating disaccharide attached by polypeptides to form a lattice that surrounds and protects the cell
this links adjacent rows
polypeptides
destruction caused by rupture of the plasma membrane and the loss of cytoplasm
lysis
cell walls consist of many layers of peptidoglycan
forms a thick, rigid structure
gram positive cell walls
these contain teichoic acids
gram positive cell walls
what do teichoic acids consist of
alcohol and phosphate
this spans the peptidoglycan layer and is linked to the plasma membrane
lipoteichoic acid
this is linked to the peptidoglycan layer
wall teichoic acid
what do teichoic acids do
bind and regulate the movement of cations into and out of the cell due to its negative charge
provide wall’s antigenic specificity
what are gram positive cell wall covered with
polysaccharides
these type of cells have one or VERY FEW layers of peptidoglycan
gram negative cell walls
what is peptidoglycan bonded to in gram negative cells
lipoproteins in the outer membrane
this is a gel like fluid between the outer membrane and the plasma membrane in gram negative cells
periplasm
do gram negative cells contain teichoic acid
NO
which type of cells are more susceptible to mechanical breakage and why
gram negative because there is a small amount of peptidogylcan
what does the outer membrane of gram negative cells consist of
lipoproteins, phospholipids, and lipopoysaccharides(LPS)
what does the outer membrane do in gram negative cells
provides barrier to certain antibodies by does not provide barrier to all substances
these permit passage of molecules such as nucleotides and peptides
porins
these consist of lipid A, core polysaccharides, and O polysaccharides
LPS
what does lipid A do
acts as an endotoxin when bacteria die
what does the core polysaccharide do
provides stability
what does O polysaccharide do
distinguishes species
