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A Levels Biology (9700)•9700/11/M/J/20
Question 38 from 9700/11/M/J/20

Explanation

Lipid targeting prevents easy mutational resistance

Steps:

  • Antibiotics binding proteins enable resistance via DNA mutations altering protein structure.
  • Teixobactin targets lipids, not proteins, avoiding protein mutation pathways.
  • Lipid structures form through biochemical pathways, not direct DNA coding.
  • Without DNA-coded targets, random mutations rarely confer resistance to lipid-binding antibiotics.

Why D is correct:

  • Statement 3 states lipid structure is not DNA-coded, directly explaining low resistance risk per evolutionary biology, as mutations cannot easily modify non-genetic targets.

Why the others are wrong:

  • A includes 1, which describes protein-based resistance mechanism, contradicting unlikelihood for teixobactin.
  • B includes 1, which promotes resistance development, not prevention.
  • C includes 2, a factual difference but not explanatory without 3's genetic rationale.

Final answer: D

Topic: Antibiotics

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