What is the overall purpose of DNA replication in the cell cycle?

What is the overall purpose of DNA replication in the cell cycle?

• A. To produce two identical copies of DNA for cell division
• B. To create mRNA molecules
• C. To synthesize proteins
• D. To repair damaged proteins

Answer: (A)

DNA replication serves to copy the cell’s entire genome so that, when the cell divides, both daughter cells inherit an identical set of genetic instructions. This happens during the S phase of the cell cycle and uses a semi-conservative mechanism: each new DNA molecule has one old strand and one newly synthesized strand, helping preserve the genetic sequence while allowing accurate duplication. Enzymes like helicase unwind the double helix, primase lays down RNA primers, DNA polymerases build the new strands, and ligase seals the fragments, readying the genome for separation during mitosis or meiosis. Other cellular tasks aren’t about copying the genome: making mRNA is transcription, which produces RNA templates for protein synthesis; protein synthesis itself is translation (plus transcription and other regulatory steps); and repairing damaged proteins involves proteostasis and repair pathways, not duplicating DNA.

DNA replication serves to copy the cell’s entire genome so that, when the cell divides, both daughter cells inherit an identical set of genetic instructions. This happens during the S phase of the cell cycle and uses a semi-conservative mechanism: each new DNA molecule has one old strand and one newly synthesized strand, helping preserve the genetic sequence while allowing accurate duplication. Enzymes like helicase unwind the double helix, primase lays down RNA primers, DNA polymerases build the new strands, and ligase seals the fragments, readying the genome for separation during mitosis or meiosis.

Other cellular tasks aren’t about copying the genome: making mRNA is transcription, which produces RNA templates for protein synthesis; protein synthesis itself is translation (plus transcription and other regulatory steps); and repairing damaged proteins involves proteostasis and repair pathways, not duplicating DNA.