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25 terms

Lecture 3

STUDY
PLAY
pleiomorphic
a given microbe that has multiple morphologies
important macromolecules of cells
proteins, nucleic acids, polysaccharides, lipids
proteins
role: structural, catalytic
location: cytoplasm, cell surface, secreted)
nucleic acids
role: info, structural (RNA), catalytic (RNA)
location: genome, plasmids, ribosomes, cytoplasm
polysaccharides
role: structural, energy storage
location: peptidoglycan, outer membrane, storage granules
lipids
role: structural, energy storage
location: membrane, storage granules
bacterial cytoplasmic membrane
lipid bilayer-seperates in form out
structure- glycerol core, 2 carbons form ether links to hydrophobic f.a.
3rd carbon- links to hydrophilic phosphate head
cytoplasmic membrane proteins
Integral-mem channels, transporters, energy, metabolism, chemotaxis
Secreted- transported through membrane
Peripheral- mem anchor, similiar to integral, lipoprotein with anchor
Membrane Strengthening Agents
Sterols- eukaryotes
Hopanoids-bacteria, NOT archaea
Archaea Membranes
Ether betwen glycerol and hydrophobic side chain. not ESTER
isoprene as subunit for hydrophobic side chains rather than fatty acids
major lipids of archaea
glycerold diether (20 c)
diglycerol tetraether (40 c)
cytoplasmic membrane functions
permeability barrier
protein anchor
energy conservation
transmembrane proteins
increase rate of uptake across cytoplasmic membrane of solutes with low permeability
Transport Systems
Passive- no energy needed. aquaporins
Active- requires energy. simple transporters, group translocation, ABC transporter
simple transporters
Uniporters
Symporters
Antiporters
all have 12 alpha helices
ABC Transporters
ATP binding Cassette
3 parts- periplasmic binding protein, membrane spanning transporter, atp-hydrolyzing protein
translocases
secretion of proteins
can include: toxins, enzymes for degradation of large polymers (cellulose), and enzymes or recomponents for construction of cell structures outside cytoplasm
"cell walls" of bacteria
aka peptidoglycan layer
prevents osmotic lysis, gives cell shape, located outside cytoplasmic membrane
what is peptidoglycan sensitive to?
B-lactam antibiotics
lysozymes (tears saliva, etc)
B-lactam antibiotics
penicillin
bind to and inactivates transpeptidases
which are responsible for forming oligopeptide cross links in peptidoglycan
yields weakened cell wall and lysis
peptidoglycan
glycan= long polysaccharide made of 2 amino sugars linked B-1,4
peptido- made by oligopeptide cross links. made partly of d-amino acids
gram postive cell surface
thick peptido
2 phyla= firmicutes, actinobacteria
teichoic acid- acidic polymer of modified ribitol
gram negative cell surface
thin peptido
contains LPS layer
contains porins (3 channeled passive transporters)
space between membranes- periplasm
LPS
esp Lipid A can act as endotoxin
gram stain
gram negative= pink
gram postive= purple