Bacterial Structure, Function, and Growth Flashcards
Why is the peptidoglycan layer such a great target for antimicrobial drugs?
Because it is unique to bacteria and (usually) required.
What eukaryotic protein attacks the peptidoglycan layer?
Lysozyme, by hydrolyzing the bond between N-acetylglucosamine and N-acetylmuramic acid
The building blocks of peptidoglycan are _________.
N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNac)
Lipopolysaccharide is the _________.
main lipid of the outer leaflet of the outer membrane
Lipopolysaccharide is also called ________.
endotoxin
Other than endotoxin, the outer membrane of gram-negative bacteria contains _______.
porins and lipoprotein
What does lipoprotein do?
It anchors the outer membrane to the peptidoglycan of the inter-membrane space
Describe the composition of LPS.
It connects to the outer membrane via three phospholipids (a disaccharide phospholipid called lipid A), which then connects to a core polysaccharide and finally (most distally) a repeating oligosaccharide unit called O antigen
What is the toxic component of LPS?
Lipid A (the disaccharide phospholipid)
What two vaccines (mentioned in class) are anti-capsular antibodies?
Pneumococcus and hemophilus influenzae type B
Bacteria secrete a slime called ________ that allows them to stick to ________.
glycocalyx; host cells, the world, and/or each other
Biofilm (glycocalyx) protects bacteria from _______.
phagocytosis, complement, and antimicrobial agents
List the functions of bacterial secretion systems.
(1) deliver proteins to the cell surface; (2) assemble organelles on the cell surface; (3) export proteins to the extracellular environment; and (4) inject proteins or DNA into other cells.
Describe the structure of secretion-system proteins.
They have inner-membrane rings, outer-membrane rings, and needles.
List the eukaryotic proteins that are analogous to MreB, CreS, and FtsZ.
FtsZ - tubulin; MreB - actin; CreS - intermediate filaments
Although both Gram-positive and Gram-negative bacteria have peptidoglycan, Gram-positive bacteria ___________.
have more, and the peptidoglycan is more extensively cross-linked
Teichoic acids are found on _________ bacteria and function to help __________.
Gram-positive; stabilize the outer membrane
Lipoteichoic acids connect to the _________.
lipid membrane
Capsules are composed of _________.
complex polysaccharides
____________ flagellar movement results in movement.
Counterclockwise
The cytoplasmic membranes (inner) of bacteria contains no _______, unlike animal cells.
sterols
Bacterial membranes are impermeable to ______ molecules.
charged
Heterotrophic bacteria require ________, while autotrophic bacteria require _______.
organic carbon; CO2
List the categories of O2 requirement.
Strict aerobe (requires O2, will die without); strict anerobe (does not require O2, will die with O2); indifferent anerobe (does not need O2, but can survive in the presence of O2); facultative anerobe (usually needs O2, but can survive without)
The beta-lactams (penicillin, cephalosporin), vancomycin, and cycloserine all inhibit ________.
formation of the peptidoglycan layer
Endospores are produced by some _________ bacteria.
Gram-positive
