Biology 9700 · AS & A Level · Antibiotics

Antibiotics — practice question

Organism X makes molecule Y, and this molecule inhibits the activity of $70\text{S}$ ribosomes. An experiment was performed to examine the effect of Y on bacterial cells. An agar plate covered with bacteria growing across its entire surface had four wells made in the agar. Each well received a different substance, and the agar plate containing the bacteria was incubated for one week. The diagram shows the outcomes after one week. Which conclusions can be drawn from these results?

  • Amolecule Y functions as an antibiotic; molecule Y cannot be released from cells of organism X; molecule Y would also affect the synthesis of proteins from nuclear DNA in a human cell
  • Bmolecule Y functions as an antibiotic; molecule Y cannot be released from cells of organism X; molecule Y would not affect the synthesis of proteins from nuclear DNA in a human cell
  • Cmolecule Y functions as an antibiotic; molecule Y can be released from cells of organism X; molecule Y would also affect the synthesis of proteins from nuclear DNA in a human cell
  • Dmolecule Y does not function as an antibiotic; molecule Y cannot be released from cells of organism X; molecule Y would also affect the synthesis of proteins from nuclear DNA in a human cell

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