1261449
Description
Flashcards by Nicole Bolo, updated more than 1 year ago
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Created by Nicole Bolo
over 10 years ago
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| Question | Answer |
| structure present in Archaea instead of peptidoglycan | pseudomurein |
| another term for peptidoglycan | Murein |
| 2 fxns of peptidoglycan | maintenance of the cell integrity, resistance from osmotic lysis |
| 2 sugar backbones of peptidoglycan | NAG (N-accetyl glucosamine) & NAM (N-acetylmuramic acid) |
| tetra amino side chains | L-alanine, D-glutamic acid , DAP (Diaminophenelic acid) in G(-) or L-lysine in G(+), D-alanine |
| bonds that connect the peptidoglycan monomers | - Glyosidic bonds |
| process which create the cross bridging between peptides | Transpeptidation |
| Usable form of aa | L-form |
| advantage for having D-form aa | protection against digestion of proteases (not easily detected) |
| peptide cross link in G- | DAP - D-ala |
| peptide cross link in G+ | L-lys to D-ala |
| characteristic of G- cell wall | dense |
| characteristic f G+cell wall | thick peptidoglycan layer |
| cause of thick peptidoglycan layer | peptide interbridge (made up of 5 glycine) |
| Starting material in peptidoglycan synthesis | fructose-6-phosphate |
| To which molecule does NAG interact with to form NAM? | Uridine Diphosphate |
| How is NAG converted to NAM? | Lactyl group is added to C-3 of UDP-NAG to form UDP-NAM |
| T or F: tRNA & ribosomes are used in peptide addition in peptidoglycan synthesis | False (NOT used) |
| transport lipid which carries NAG-NAM-5AA | undecaprenyl-monophosphate |
| 2 processes occurring in the cell wall upon peptidoglycan synthesis | Transglycosylation & Transpeptidation |
| examples of beta-lactam antibiotics | penicillin, cephalosporins |
| mechanism of beta-lactam antibiotics | the absence of the peptide bridge due to the binding with transpeptidase enzyme |
| example of Glycopeptide antibiotics | vancomycin |
| mechanism of glycopeptide antibiotics | prevents the formation of peptide cross-links by bindingto the penta-peptide side chains |
| mechanism of bacitracin | Prevents the dephosphorylation of bactoprenol resulting to the inhibition of monomer transport |
| 3 types of peptidoglycan hydrolases | 1. Glycan-strand hydrolyzing enzyme, 2. Endopeptidase hydrolyzing enzyme, 3. N-acetylmuramoyl-L-amanine amidase enzyme |
| mechanism of Glycan-strand hydrolyzing enzyme | - Hydrolyzes the B-1,4 glycosidic bonds bet NAM& NAG |
| mechanism of Endopeptidase hydrolyzing enzyme | Breaks the cross link between the peptides |
| mechanism of N-acetylmuramoyl-L-amanine amidase enzyme | breaks the connection bet. the sugar backbone & aa side chain |
| describe: G+ cell wall | - Thick peptidoglycan - Thin periplasmic space |
| unique structures in G+ cell walls | teichoic acids & lipoteichoic acids |
| fxn of teichoic acids | virulence factor required for host colonization |
| Teichoic acids which extend until the cell membrane | lipoteichoic acids |
| fxn of Lipoteichoic acids | structural support |
| components of Lipoteichoic acids | glycerol or ribitol |
| Most abundant protein in OM | Braun’s lipoprotein |
| 3 parts of lipopolysaccharide | Lipid A, core polysaccharide, O side chain |
| fxn of O side chain | bacteria become less susceptible to detection of antibodies |
| special structures in outer membrane | porins |
| 4 reagents in Gram staining | Crystal violet, iodine, ethanol, safranin |
| differential sep in G staining | ethanol decolorization |
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