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what is the peptidoglycan structure And how do you insert a monomer?
- -composed of sugars and proteins
- -composed of NAM and NAG with 5 amino acids linked to the NAM sugar
- - Autolysins cut the cell wall, transglycosidase link the sugars, transpeptidase crosslink the peptide side chains
Describe Gram positive Cell wall
- -thick layer of peptidoglyan consisting of sheets with interconnected glycan chains crosslinked via tetrapeptide chains
- -teichoic acid/lipoteichoic acid-stick out above the peptidoglycan.
- -various sugars like D-alanine are attached.
- -some are covalently joined to the peptidoglycan molecule (wall teichoic acids, linked to NAM) in which these help stabilize the gram positive cell wall.
- -the ones linked to the cytoplasmic membrane is the lipoteichoic acid
- -gves the cell its negative charge
Describe Gram negative cell wall
- -contains a thin layer of peptidoglycan
- -outside is the outer membrane (bilayer embedded with proteins and joined to the peptidoglycan by lipoproteins)
- -embedded with porin proteins which allows molecules in periplasmic space
- -lipoprotein link plasma membrane and outer membrane to the periplasma's peptidoglycan
- -Lipopolysaccharide (LPS): also known as endotoxin.
- -Lipid A is found in most Gram negatives. the core polysaccharide is conserved in specific genus or species, and the O side chain is variable within species
- -periplasma is the space between the plasma membrane and the outer membrane
- -contains peptidoglycan and enzymes
- -peptidoglycan side-chains are directly linked, there is no interbridge
- directed movement of bacteria in response to chemical stimuli in the environment
- -flagellum is responsible for motility
- -movement is not a straight line
- -change of rotation of the flagellum causes the cell to tumble
- -cells tumble less frequently when they are closer to attractant and when they are moving away from a repellent resulting in longer runs
Describe what Ribosomes are