A Levels Biology (9700)•9700/13/O/N/21
Explanation
Gene Activation Triggers mRNA Transcription
Steps:
- Gene activation unwinds DNA at the promoter region.
- RNA polymerase binds and transcribes the gene into complementary RNA.
- For a protein-coding gene like protease, the initial transcript is pre-mRNA, processed to mature mRNA.
- mRNA carries the genetic code from DNA to ribosomes for translation into protease protein.
Why B is correct:
- mRNA is the direct product of transcription from an activated protein-coding gene, per the central dogma of molecular biology (DNA → RNA → protein).
Why the others are wrong:
- A: DNA is the pre-existing template gene, not formed during activation.
- C: rRNA is synthesized from separate ribosomal genes for ribosome assembly.
- D: tRNA is transcribed from tRNA genes, not the protease gene.
Final answer: B
Topic: Protein synthesis
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