8.31.2022. study questions Flashcards
Which molecule is unique to domain bacteria and not found in archaea or eukarya?
peptidoglycan
Draw the structure of peptidoglycan
NAG
NAM
tetrapeptide chain (AA)
peptide interbridge (G+ cells)
What will happen to abacterial cell if you weaken the structure of peptidoglycan?
weaken cell wall overall so then the cell could burst
What effect does lysozyme have on peptidoglycan?
disrupts the bond between NAG–NAM. more effective against G+
What effect does penicillin have on peptidoglycan?
prevents cross-linking of adjacent glycan chains by inhibiting the enzyme that normally catalyzes the cross-linking step
What gram cell types have porins and why?
gram negative. permit passage of molecules
Which molecule is unique to gram positive cells?
teichoic acids
How is the gram negative cell wall different from the gram positive cell wall?
Negative: thin layer of peptidoglycan. porins. LPS. outer membrane.
Positive: thick layer of peptidoglycan. teichoic acids.
Where is LPS found?
outer membrane of G- cell wall
What is the medical significance of LPS aka endotoxins?
- component of outer membrane of G- bacteria
- immune system can handle small quantities
- large quantities (like lots of G- in the bloodstream) are deadly
Why can mycoplasma species not be treated with penicillin?
But they do have…?
-no cell wall
- they do, however, have sterols in the cytoplasmic membrane that make it okay for mycoplasma to live without a cell wall
What staining technique is used to stain mycobacteria?
acid fast stain
Why can’t they stain mycobacteria with gram stain?
no cell wall
What are efflux pumps?
“eject pumps.” using energy to pump antibiotic drugs out of the cell, then the drugs don’t have an effect.
Why do efflux pumps need energy to function?
using difference in proton gradient to activate the pump to get stuff out of the cell and pump antibiotics out of the cell