Which of the following best explains why antibiotics are effective against bacteria but not human cells?

• A. Antibiotics are unable to penetrate the plasma membrane of human cells.
• B. Antibiotics only affect cells that reproduce by binary fission.
• C. Antibiotics require oxygen to function and human cells are anaerobic.
• D. Antibiotics target unique features of prokaryotic cells, such as peptidoglycan in the cell wall and 70S ribosomes.

Answer: (D)

Verified step by step guidance

1. Understand that antibiotics are designed to target specific structures or processes that are unique to bacteria (prokaryotic cells) and not found in human (eukaryotic) cells.
2. Identify key differences between bacterial and human cells, such as the presence of peptidoglycan in bacterial cell walls and the type of ribosomes (70S in bacteria vs. 80S in humans).
3. Recognize that antibiotics interfere with bacterial cell wall synthesis or protein synthesis by targeting these unique features, which are absent in human cells, making human cells unaffected.
4. Evaluate the incorrect options by considering that antibiotics can penetrate human cell membranes in some cases, not all bacteria reproduce by binary fission exclusively, and oxygen requirement is not a factor in antibiotic effectiveness.
5. Conclude that the best explanation is that antibiotics target unique prokaryotic features, which explains their selective toxicity against bacteria but not human cells.