Prokaryotes (part 2) Flashcards
Parts of the Cell Envelope
Cell Wall
Cell Membrane
Functions of cell wall
Give shape and rigidity Contributes to pathogenicity Protection Site of action of antibiotics Used to differentiate bacteria
Cross-linking of cell wall
Transpeptidase
Prokaryotes Division
Gracilicutes
Firmicutes
Tenericutes
Mendosicutes
Thin cells walls, implying a gram negative type cell wall
Gracilicutes
Cyanobacteria
Thick and strong skin, indicating gram positive type cell wall
Firmicutes
Cyanobacteria
Pliable and soft nature, indicating the lack of a rigid cell wall
Tenericutes
Mycoplasmas
With unusual cell wall, lack conventional peptidoglycan
Mendosicutes
Archaea
A polymer of disaccharides linked by polypeptides found in the cell wall of bacteria
Peptidoglycan
Another name for peptidoglycan
Murein
Mucopeptide
Two molecules that make up the peptidoglycan
NAG and NAM
NAG
N-acetylglucosamine
NAM
N-acetylmuramic
Has a thick layer of peptidoglycan
Gram positive bacteria
Space between cell wall and cell membrane
Periplasmic space
Consist primarily of an alcohol and phosphate
Teichoic Acid
Function of the Teichoic Acid
Bind and regulate the movement of positive ions into and out of the cell
Two types of teichoic acid
Lipoteichoic acid
Wall teichoic acid
Spans the peptidoglycan layer
Linked to the plasma membrane
Lipoteichoic Acid
Linked to the peptidoglycan layer
Wall teichoic acid
Contains one or a very few layers of peptidoglycan and an outer membrane
Gram negative bacteria
Region between the outer membrane and the plasma membrane
Periplasm
Found in the periplasmic space in gram negative bacteria
Peptidoglycan
Gram positive characteristics
Thick PG
With TA
Without OM
Gram negative characteristics
Thin PG
Without TA
With OM
Outer membrane compositions
Lipopolysaccharides (LPS)
Lipoproteins
Phospholipids
Acts as an antigen
Distinguishes between species
Buried within the OM
LPS
Functions as endotoxin when cell dies
Responsible for the symptoms assoiciated with infections by G(-) bacteria
Lipid A
Importance of LPS
Imparts strong negative charge
Stabilization of membrane
Acts as endotoxin
Protective barrier
Gram stain mechanism
Crystal violet
Iodine
Alcohol
Safranin
Gram positive genera that show an increasing number of gram negative cells as the culture ages
Gram variable cells
Damage cell wall by hydrolyzing linkages between NAM and NAG residues
Lysozyme