transport
what are the different types of membrane proteins and where are they located in the phospholipid bilayer?
integral membrane proteins are firmly embedded in the membrane and peripheral membrane proteins have one portion anchored in the membrane
what trasnport is driven by the energy in the proton motive force? and give an example of this transport
1. simple transport
2. lac permease of E. coli
what is a teichoic acid?
repeats of glycerol phosphate or ribitol phosphate
what is endotoxin?
the toxic component of LPS (particularly lipid A)
what is lipid A?
fatty acids link to disaccharide through amino groups
what are the three major classes of transport systems in prokaryotes? and do they require energy? (3)
simple transport, group translocation, ABC system all require some form of energy (ATP or proton motive force)
what transport uses energy from chemical modification of the transported substance driven by phophoenolpyruvate? and give an example of this
1. group translocation
2. the PTS in E.coli
this cell wall commonly has teichoic acids embedded in their cell wall
gram positive
what is O-polysaccharide (O-antigen)?
repeats of 4-5 sugar sequences, usually branched
what is the core polysaccharide?
it connects to lipid A through ketodeoxyoctane (KDO)
what transport uses periplasmic binding proteins that are involved and have energy coming from ATP?
ABC transport
true or false: D-alanine , D-glutamic acid are present in proteins
false
what is the difference between lipoteichoic acids and wall teichoic acids
lipoteichoic acids are teichoic acids that are covalently bound to the membrane lipids while wall teichoic acids are teichoic acids that are covalently bound to the peptidoglycan
what is a porin?
what is the periplasm?
space located between cytoplasmic and outer membranes and has a gel like consistence
how much of the cell wall in gram + and gram - contain peptidoglycan
gram positive contains up to 90% and gram negative contains up to 10% because gram - cell wall is mostly composed of outer membrane lipopolysaccharide layer
what are the roles of the membrane?
the permeable barrier must transport polar and charged molecules through transport proteins against the concentration gradient. the protein anchor holds transport proteins in place and its conserves energy through thr generation of proton motive force
what is the LPS composed of?
lipid A, core polysaccharide and O-polysaccharide
what is the smallest free living organisms capable of self replication and has a triple layer membrane that contain lipoproteins
mycoplasmas
what is the archaeal cell wall composed of?
it lacks a peptidoglycan and typically has no outer membrane. It has a pseudomurein which is a polysaccharide similar to petidoglycan and is composed of G amd T. but keep in mind some cell walls of archaea lack pseudomurein
what are the nutrient transport? and how do they work?
1. uniporters; transport in one direction across the membrane
2. symporters; function as co-transporters
3. antiporters; transport a molecule across the membrane while simultaneously transporting another molecule in the opposite direction
what is the peptidoglycan composed of?
polysaccharides composed of G and M and peptides composed of L-alanine, D-alanine, D-glutamic, acid and L-lysine/DAP
what is the difference in the cell wall structure of the gram negative and gram positive bacteria?
gram negative cell wall is a bilayer containing LPS and peptidogylcan which gram positive cell wall is monolayer consisting of only the peptidoglycan
what are the characteristics to the archaeal membranes? (4)
Hint: Linkage, what it lacks, major lipids and what type of layer :)
ether linkages in phosphoplipids rather than ester linkages
lack fatty acids but have isoprenes instead
the major lipids are glycerol diethers and tetraethers
can exist as monolayers, bilayered or mixed
mycobacteria have a 3 layer cell wall that contains a layer of ________ _______ and additional _________ and ________ connect the 3 layers
1. mycolic acids (long chain fatty acids, waxy)
2. lipomannas
3. arabinoglycan