Lecture 8-10 Prokaryote Structure & Function Flashcards
Include bacteria and archaea
prokaryote
Include animals, plants, fungi, and protists
eukaryotes
DNA in a prokaryote
one circular chromosome, not in a membrane
DNA in a eukaryote
paired chromoes in nuclear membrane
Presence of histones indicates
eukaryote
Have “histone-like” proteins
archaea
Prokaryotes typically don’t have
organelles
Makes up cell wall in bacteria
peptidoglycan
Makes up cell wall in some eukaryotes
polysaccharides
Makes up cell wall in archaea
pseudomurein
Binary fission
method in which a bacteria reproduces
Monomorphic
bacteria having one shape that is genetically coded
Pleomorphic
bacteria having different shapes depending on their enviroment
rod –>
bacillus
sphere –>
coccus
slight bending –>
spiral
one –>
single
pair –>
diplo-
chain –>
strepto-
group of 4 –>
tetrad
cluster –>
staphylo-
comma-shaped –>
vibrio
loose waves –>
spirillum
tight waves –>
spirochete
Sugary outside of a bacterial cell wall
glycocalyx
2 parts of glycocalyx
capsule and slime layer
Capsule
neatly organized, hard to remove, attached firmly
Slime layer
unorganized and loose, easy to remove, extends very far out
Purpose of glycocalyx
allows cell to attach, protects again phagocytosis (water loss), aids in biofilm formation and pathogenesis
Purpose of cell wall
prevents osmotic lysis (explosion caused by water movement), provides shape and rigidity and structural support, provides protection
What cell wall is made of
peptidoglycan
The cell envelope includes
capsule, cell wall, and cell membrane
What is peptidoglycan
a polymer of disaccharide
Structure of peptidoglycan
NAG and NAM connected via a glycosidic bond beta-1,4 linkage
Significance of lysozyme to peptidoglycan
enzyme can break down the glycosidic bond
The peptidoglycan in Gram-positive bacteria is linked via
polypeptides
Effect of penicillin on peptidoglycan
stops enzyme from building polypeptide bridges in Gram-positive bacteria
Teichoic acid
“rebarb” phosphate polymer that provides structural support in Gram-positive bacteria
Lipoteichoic acid
touches into cell membrane
The cell envelope of a Gram-negative bacteria is more like a
sandwich
Gram-negative bacteria have ____ peptidoglycan.
less
Basic structure of Gram-negative bacteria cell wall
plasma membrane –> periplasm –> peptidoglycan –> outermembrane –> lipopolysaccharides
Periplasm
space between plasma and outer membrane
2 components of Gram-negative cell wall
peptidoglycan and outer membrane
Lipopolysaccharides (LPS)
extending carbon chains from outer membrane that protect cell against entry of unwanted molecules (antibiotics)
What allows for the movement of H20 and uncharged molecules through the outer membrane
porin
3 main components of the LPS
Lipid A (anchor & endotoxin), core polysaccharide (conserved across many species), variable O-polysaccharide antigen (various depending on strain)
Significance of the LPS
repels hydrophobic (nonpolar) molecules that may otherwise cross through the membrane
What are resistant to mechanical stress
Gram-positive (thick peptidoglycan)
What excel in damp enviroments
Gram-negative
Components of an acid-fast cell wall
waxy lipid (mycolic acid) bound to peptidoglycan
What that have acid-fast cell walls
mycobacterium and nocardia
Mycoplasmas
lack cell walls, have lipids in plasma membrane, are not affected by penicillin, will not gram stain
Archaea are wall-less or have walls of
pseudomurein (don’t have NAM)
Areotaxis
oxygen concentration tactic stimuli
Phototaxis
photon intensity tactic stimuli
Chemotaxis
chemical compound concentration tactic stimuli
flagella that are uniformly distributed over the body
peritrichous
one singular flagella
monotrichous
multiple flagella arising from the same point
lophotrichous
two sides flagella
amphitrichous
How does motility work with one peritrichous?
the bundled flagella rotate, motor changes to the other way to turn around
How does motility work with a reversible flagella?
the flagella rotates one direction for forward and one direction for backwards
How does motility work with unidirectional flagella
the flagella only rotates one way, to turn around the cell has to stop and reorientate
Substance that makes up a flagella
filament
Anchors the flagella to the outer membrane
hook
Bottom of the flagella connection within the membrane
basal body
Proteins that make up the flagella motor
mot and fli proteins
Protein that receives signal to turn
fli protein
What the motor of flagella uses as energy to turn
proton flow
There are fewer pili than
fimbriae
Is involved in surface attachment and biofilm formation
fimbriae
Is involved in gene transfer and surface attachment
pili