Final answer:
The DNA unwinding process leads to transcription, where a strand of mRNA is created. This mRNA is an exact complementary transcript of the template DNA strand, excluding the replacement of thymine with uracil.
Step-by-step explanation:
The process and product of a double-stranded DNA when it first unwinds is transcription, resulting in the formation of messenger RNA (mRNA). During transcription, the double helix of DNA unwinds, and an enzyme called RNA Polymerase synthesizes a single-stranded mRNA using one DNA strand as a template. The mRNA sequence is complementary to the DNA template strand, with uracil (U) replacing thymine (T) wherever adenine (A) appears in the DNA.
This process involves creating an mRNA molecule that serves as a template for protein synthesis during translation. Since DNA replication is concerned with copying DNA to produce two complementary strands, and not with mRNA production, the correct answer to the student’s question is 'a) Transcription, mRNA'. Moreover, DNA replication is an anabolic process, as it involves the synthesis of new molecules.