Compare and contrast the effect of antibiotics on bacterial and eukaryotic proteins, Flashcards
How do antibiotics typically affect bacterial proteins?
Antibiotics often target specific bacterial proteins or enzymes essential for survival, such as those involved in cell wall synthesis, protein synthesis, or DNA replication, leading to bacterial cell death or growth inhibition.
Why do antibiotics generally have little effect on eukaryotic proteins?
Antibiotics are designed to target structures or processes unique to bacteria, such as bacterial ribosomes, which differ from eukaryotic ribosomes, thus sparing eukaryotic cells from damage.
Which antibiotic targets bacterial cell wall synthesis, and why doesn’t it affect eukaryotic cells?
Penicillin targets bacterial cell wall synthesis by inhibiting enzymes that cross-link peptidoglycan layers. Eukaryotic cells lack peptidoglycan, so penicillin does not affect them.
How does the antibiotic tetracycline affect bacterial cells, and why is its effect different on eukaryotic cells?
Tetracycline binds to the bacterial 30S ribosomal subunit, inhibiting protein synthesis. Eukaryotic cells have a different ribosomal structure (80S), so tetracycline does not bind effectively and has minimal impact.
Provide an example of how data can support the differential effect of antibiotics on bacterial versus eukaryotic cells.
Data showing the growth inhibition of bacterial cultures treated with streptomycin (which targets bacterial ribosomes) compared to unaffected eukaryotic cell cultures demonstrate the selective targeting by antibiotics.
What role does selective toxicity play in the effectiveness of antibiotics?
Selective toxicity refers to the ability of antibiotics to target bacterial proteins without harming eukaryotic cells, making them effective in treating bacterial infections without damaging the host.
How do aminoglycoside antibiotics differ in their effects on bacterial and eukaryotic cells?
Aminoglycosides, like gentamicin, target the bacterial 30S ribosomal subunit, disrupting protein synthesis. They do not affect eukaryotic ribosomes, leading to selective inhibition of bacterial growth.
Why might some antibiotics, such as chloramphenicol, have toxic effects on eukaryotic cells?
Chloramphenicol can affect mitochondrial ribosomes in eukaryotic cells because they resemble bacterial ribosomes, leading to potential toxicity in human cells.
What data would support the claim that antibiotics selectively target bacterial proteins?
Experimental data showing that bacterial growth is inhibited by antibiotics like erythromycin, while eukaryotic cell growth remains unaffected, supports the claim of selective targeting.
How does the structural difference between bacterial and eukaryotic ribosomes support antibiotic selectivity?
The structural differences (e.g., 30S/50S in bacteria vs. 40S/60S in eukaryotes) allow antibiotics like tetracycline and macrolides to specifically bind and inhibit bacterial ribosomes, sparing eukaryotic cells.