Answer: Cross-linking DNA by displacing Cl- with purine N-donors (N7 of guanine), distorting DNA helix.
- A Cross-linking DNA by displacing Cl- with purine N-donors (N7 of guanine), distorting DNA helix
- B Generally releasing free toxic platinum ions that poison the entire cell under most conditions encountered
- C Directly inhibiting a specific metabolic enzyme without touching DNA as frequently observed in practice
- D Binding to and disrupting the lipid bilayer of the cell membrane in many documented cases
Correct answer: A. Cross-linking DNA by displacing Cl- with purine N-donors (N7 of guanine), distorting DNA helix
Explanation: Cisplatin undergoes aquation (Cl- replaced by H<sub>2</sub>O), then bifunctionally binds N7 of adjacent guanines, forming 1,2-d(GpG) intrastrand cross-links that kink DNA and block replication.
The three common coordination geometries: octahedral (6 ligands), tetrahedral (4 ligands), and square planar (4 ligands in one plane).
Concept context
Study of compounds where a central metal atom is bonded to surrounding ligands. Covers nomenclature, types of isomerism, bonding theories (VBT, CFT), and applications in medicine, photography, and industry.