Duplication of chromosomes occurs during S phase of the cell cycle. Duplication requires the separation of complementary DNA strands to allow for DNA replication. Which of the following statements best explains how weak hydrogen bonds function better in this situation than stronger bonds would?

Question

Complementary DNA strands are easily mutated by environmental factors. These changes lead to evolution. Therefore, weak hydrogen bonds support continued evolution by allowing mutations during DNA replication.
Hydrogen is used in many metabolic functions; therefore its function connecting complementary DNA strands stores hydrogen atoms for use in the G2 phase of the cell cycle.
Duplicated DNA molecules must be extremely flexible in order to fit sister chromatid pairs into the nucleus of a eukaryotic cell. Weak hydrogen bonds between complementary strands are easily bent and modified, allowing for this type of flexibility.
Complementary DNA strands are separated or “unzipped” for the replication process. Weak hydrogen bonds between complementary strands are easily disrupted during DNA replication because they are not high-energy chemical bonds.

GPT-4o mini · Answer

The statement that best explains how weak hydrogen bonds function better in the context of DNA replication during the S phase of the cell cycle is:

"Complementary DNA strands are separated or 'unzipped' for the replication process. Weak hydrogen bonds between complementary strands are easily disrupted during DNA replication because they are not high-energy chemical bonds."

This statement accurately reflects the role of hydrogen bonds in DNA stability and replication. The hydrogen bonds between complementary bases (adenine-thymine and guanine-cytosine) are indeed weak compared to covalent bonds and allow the two strands of the DNA helix to be easily separated. This separation is critical for the replication process, as each strand serves as a template for synthesizing a new complementary strand. Stronger bonds would make the unzipping process much more difficult, hindering DNA replication.