Making a copy of DNA is known as what?

• A. Transcription
• B. Translation
• C. Mutation
• D. DNA replication

Answer: (D)

DNA replication. The double helix unwinds, and each strand serves as a template for a new complementary strand. Nucleotides are added by DNA polymerase according to base-pairing rules (A with T, G with C), with primers marking the starts. The leading strand is synthesized continuously, while the lagging strand is made in short fragments called Okazaki fragments that are joined later. The result is two identical DNA molecules, each containing one old strand and one new strand—the semi-conservative mechanism. This copying happens so a cell can divide its genome during the S phase of the cell cycle. It’s different from transcription, which makes RNA from DNA, and from translation, which makes protein from RNA; and it’s not about a change in sequence, which would be a mutation.