Microbiology Ch. 4
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Microbiology Ch. 4
Prokaryotic Eukaryotic Cell Anatomy
Anatomy of Prokaryotic and Eukaryotic Cells
define prokaryote and eukaryote?
Prokaryote- NO nucleus
functional anatomy of Prokaryote?
1 circular chromosome not enclosed in membrane
peptidoglycan cell walls
binary fusion division
what are histones?
what makes DNA coil and wrap up tight
Functional Anatomy of Eukaryote?
paried chromosomes enclosed in nuclear membrane
polysaccharide cell walls
mitotic cell division
basic shapes to prokaryote?
Spirrila- spiral/cork screw
: star shaped stella, square shaped haloarcula
average size of prokaryote?
0.2-1.0 um x 2-8 um
most bacteria are how many shapes?
monomorphic - meaning 1 shaped
a few bacteria can have multiple shapes which is defined as?
pleomorphic - multiple shapes
how are cocci arranged?
Pairs - diplococci
how are bacilli attached to each other?
end to end, never in middle
arrangement of bacilli?
there is no staphylo arrangement in rods
shapes of spiral bacteria?
vibro- comma shaped, only one bend
spirilla- rigid, helical shape
spirochetes- flexible, helical shape
name the outer structures?
characteristics of glycocalyx?
outside cell wall
protects from dehydrations, and limit outward diffusion
how is glycocalyx organized?
composed of sugards to allow for attachment to surfaces
if the outer cell wall of cell is unorganized and loose what is it called?
if outer cell wall of cell is organized what is it called ?
during a negative stain what is the difference between capsules adn slime layers?
capsules are more regular and organized looking
slime layer are more diffuse and less organized
function of flagella?
characteristic of flagella?
consist of chains of flagellin
attached to a protien hook
anchored to wall and membrane by basal body
on both ends- amphitrichous
2 or more on one or both ends- lophotrichous
all over the cell- peritrichous
how do flagella move?
chemotaxis- directional movement according to chemical gradient. tumble and run. toward (attractant) or away (repellant)
phototaxis- movement according to light gradient
describe what tumble and run is?
flagella move in the direction of the attraction. the runs are longer (movement in 1 direction) and the tumble is less (stop and spin).
what are axial filaments?
endoflagella - flagella on inside of cell
located in spirochetes (create the spiral pattern of spiral bacteria)
anchored at one end of cell
rotation causes cell to move
what are fimbriae?
hairlike projections that allows for attachment so microbes can colonize.
what are pili?
allow for transfer of genetic material from one cell to another.
usually longer then fimbriae
cells usually one have 1 or 2
describe the cell wall?
determines the shape
in some cases, recognized by host immune system
target for antibiotics
prevent osmotic lysis
made of peptidoglycan (prokaryote)
gram positive cell wall?
in acid fast cells, contain mycolic acid
help regulare movement of cations
polysacharides provide antigenic variation
gram negative cell wall?
thin peptidoglycan ,
no teichoic acids
describe the extra outer membrane of gram negative cell wall?
in gram positive cell wall what does techoic acid do?
lipotechoic acid lins to plasma membrane
wall techoic acids link to peptidoglycan
in gram negative cell wall what does lipopolysaccharides do?
barrier to antibiotics and surface molecules/antigens are useful in identification.
in gram negative, what does a strong negative charge protect from?
how gram stain works ?
if gram positive-
dehydrates or disolves peptidoglycan and crystal violet/iodine stuck inside cell
if gram negative-
alcohol dissolves outer membrane and leaves holes in peptidoglycan. the crystal violet and Iodine is washed out.
what does lysozymes and penicillin do to cell walls?
lysozyme digests disaccharide in peptidoglycan
penicillin inhibits peptide-bridges in peptidoglycan (why it is given to gram positive bacteria b/c they have more peptidoglycan )
characteristics of plasma membrane?
fluid mosaic model- self healing puncture proof structure
contains peripheral, integral, transmembrane proteins
enzymes for ATP production
photosynthetic pigments on foldings called chromatophores or thylakoids
what damages plasma membrane?
polymyxin antibiotics (neosporin)
types of movement across membrane?
simple diffusion- movement from high to low concentration
osmosis- water diffusion
facilitated diffusion- transporter protiens
active transport (against gradient)- transporter protiens/ATP
what is cytoplasm?
stuff inside plasma membrane
characteristics of cytoplasm?
nuclear area has nucleoid
inclusions- liquid, gas or other substances in cell
list of inclusions
protien covered cylinders
iron oxide reserves
what are endospores?
durable, resistant form
protect agains desiccation, heat and chemical
return to active form (vegetation state)