Suppose a scientist working on a new drug for cancer developed a chemical that irreversibly breaks the hydrogen bonds in the DNA molecules within cancerous cells but leaves all of the covalent bonds intact. Hydrogen bonds are relatively weak compared to covalent bonds, and they are routinely broken and reformed as the DNA molecule is replicated in a normal cell. Their stability is nonetheless critical for maintaining certain aspects of the structure and function of the DNA molecule. Based on this scenario and your knowledge of DNA, how would this newly discovered chemical affect the ʺmolecule of heredityʺ in a human cancer cell?
A) It would allow the DNA molecule to function normally except during replication.
B) It would break the individual strands of the DNA molecule apart, preventing it from functioning normally.
C) It would break the two strands of the DNA molecule apart, preventing it from functioning normally.
D) It would result in constant DNA replication within the cell.

Question

Quizplus · Accepted Answer

Hydrogen bonds in DNA are crucial for holding the two strands of the double helix together. Breaking these bonds would separate the strands, disrupting the normal function of DNA, including replication, transcription, and repair processes. Covalent bonds maintain the integrity of each individual strand by linking nucleotides together, so breaking hydrogen bonds affects the interaction between strands, not the structure of the strands themselves.

Suppose a Scientist Working on a New Drug for Cancer