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GCSE Biology · key term
A single-stranded RNA molecule that carries genetic information transcribed from a gene to a ribosome.
Used by Edexcel
Specification 3.8B, 3.9B · Paper 1
Revise: Transcription: Non-coding DNA and mRNA SynthesisThe DNA remains as the cell's stored genetic information, so the relevant sequence is first transferred to a temporary, single-stranded molecule called messenger RNA, or mRNA. This first stage of protein synthesis is transcription.
A single-stranded molecule that carries a copy of a gene's instructions to a ribosome.
For a complete description, state that the DNA unwinds, name RNA polymerase, identify its binding to the non-coding DNA in front of the gene, and explain that RNA nucleotides are joined to form complementary mRNA.
Do not describe mRNA merely as a “copy” of DNA. State that its base sequence is complementary to the DNA sequence.
Build explanations as a complete causal chain: non-coding DNA variant → altered RNA polymerase binding → altered transcription → a different quantity of mRNA → a different quantity of protein → possible change in phenotype.
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