A new drug is developed thatinhibits formation of the flagellar filament by impairing production of the protein flagellin. Is this going to be a good drug?
A. Potentially-it would definitely only impair bacteria, but wouldn't matter for the ones that don't use a flagellum to move around.
B. Potentially-if it could be shown that it also didn't impair the production of the eukaryotic flagellum.
C. No-our eukaryotic cells depend on flagella to move around in our body, and this would impair that function.
D. No-bacterial flagella are produced using microtubules, not the protein flagellin. This drug would be useless in eliminating bacteria.
A new drug is developed that targets and binds to the lipid A portion of LPS from Gram-negative bacterial cells. This drug shows a high degree of activity and binding in a test tube setting against purified lipid A. Based on this information,
A. we should fast track this drug and get it out to physicians immediately to help prevent toxic/septic shock in humans.
B. we should do some animal testing with whole Gram-negative cells and the drug before we jump to any conclusions.
C. we should next proceed by moving to testing in a test tube using whole Gram-negative cells to see if it binds with the same strength.
D. we should abandon the drug entirely. Binding to lipid A won't kill the bacteria, so the drug is useless to develop further. It wouldn't help humans who have septic shock at all.
A research lab is trying to produce new antibiotics. They come up with drugs that detach the hydrophilic heads from the phospholipids in plasma membranes. This drug
A. would be highly toxic and completely useless for human beings-we also have plasma membranes with hydrophilic head groups
B. would be highly toxic only to bacteria, making it an excellent drug to develop and test further. Humans have a different phospholipid structure in their cell plasma membranes than bacteria.
C. would generally not be toxic enough to damage Gram-negative bacteria, as their plasma membranes lie under a thick layer of peptidoglycan.
D. would be highly toxic for human beings, but might be useful as a topical antibiotic skin cream. The top layer of skin cells is dead anyway, so it wouldn't matter if this damaged those cells. It could NOT be taken internally, though, by human beings.
A research laboratory is investigating environmental factors that would inhibit the growth of Archaea. One question they have is if adding the antibiotic penicillin would be effective in controlling their growth.
What do you think the outcome would be if they tried this?
A. The penicillin wouldn't affect the Archaea because it prevents crosslinking of peptidoglycan-Archaea don't have this compound in their cell walls.
B. The penicillin will inhibit cell wall formation in the Archaea, killing them.
C. The penicillin will slow down the growth of the Archaea by damaging the cell wall, but they will still be able to grow somewhat.
D. The penicillin will enhance the growth of the Archaea by providing a rich nutrient source.
A newly developed antibiotic drug shows promise by inhibiting prokaryotic 70S ribosomes in initial studies. However, when animal studies are begun, it's noted that it also inhibits growth of animal cells.
Aren't prokaryotic ribosomes different from eukaryotic ribosomes? How can this be happening?
A. Perhaps the ribosomes aren't as different as we thought, so a drug can affect and impair both of them.
B. While the proteins made in the cytosol of eukaryotic cells are, indeed, produced from the 80S eukaryotic ribosome, mitochondria and chloroplasts possess 70S ribosomes. This drug might be impairing the activity of chloroplasts in animal cells.
C. While the proteins made in the cytosol of eukaryotic cells are, indeed, produced from the 80S eukaryotic ribosome, mitochondria and chloroplasts possess 70S ribosomes. This drug might be impairing the activity of mitochondria in animal cells.
D. Perhaps the scientists accidently combined their cultures of animal and bacterial cells-this might indicate an impairment in growth in the culture. In reality, it's still just impairing the bacterial cells.
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