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GCSE Biology · key term
Messenger RNA: a molecule that carries a copy of a gene's instructions from DNA to a ribosome.
Used by Edexcel and OCR
Specification 3.8B · Paper 1
Messenger RNA: a single-stranded RNA molecule that carries a copy of a gene’s instructions to a ribosome.
Revise: Translation: Ribosomes, Codons and PolypeptidesDuring transcription, these instructions are copied into messenger RNA, or mRNA. Translation is the next stage: the mRNA instructions are used to assemble an amino acid chain.
Specification B1.2d · Paper 1 (Foundation), Paper 3 (Higher)
Messenger RNA: a molecule that carries a copy of a gene's nucleotide sequence from the nucleus to a ribosome.
Revise: Protein synthesisComplementary RNA nucleotides line up and join to form a molecule of messenger RNA (mRNA). This copies the genetic information in the gene; the entire DNA molecule is not copied.
Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Higher), Paper 4 (Higher)
Revise: Protein SynthesisThe cell makes a copy of the gene's information in the form of mRNA. mRNA means messenger RNA: it acts as a temporary messenger carrying the information from that gene. This is the biologically correct interpretation of the specification wording that “a copy of a gene is made from messenger RNA”: the copy is made of mRNA from the DNA gene, not the other way round.
Distinguish the roles: mRNA carries the genetic instructions; tRNA carries amino acids; the ribosome is where amino acids are linked.
A codon is a triplet on mRNA. An anticodon is a complementary triplet on tRNA.
When describing translation, connect the order of mRNA codons to the order of amino acids in the polypeptide.
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