Pearson Edexcel · GCSE · Biology
Course version: 1BI0 · Version from Sept 2016
3.8B Describe the stages of protein synthesis, including transcription and…
Full specification wording
Topic 3 – Genetics: 3.8B Describe the stages of protein synthesis, including transcription and translation: a RNA polymerase binds to non-coding DNA located in front of a gene b RNA polymerase produces a complementary mRNA strand from the coding DNA of the gene c the attachment of the mRNA to the ribosome d the coding by triplets of bases (codons) in the mRNA for specific amino acids e the transfer of amino acids to the ribosome by tRNA f the linking of amino acids to form polypeptides
Protein synthesis has two stages.
Checked against the Pearson Edexcel 1BI0 specification (opens in a new tab) on .
- Point 6 of 20
Study notes
From the checked teaching notes for this specification point.
The idea
Protein synthesis has two stages. In transcription, RNA polymerase binds to non-coding DNA located in front of a gene, then produces a complementary mRNA strand from the coding DNA of the gene. In translation, the mRNA attaches to a ribosome. Triplets of bases (codons) in the mRNA code for specific amino acids, and tRNA transfers the matching amino acids to the ribosome. The ribosome links the amino acids together to form a polypeptide. Keep the order clear: binding, complementary strand, attachment to ribosome, codon coding, tRNA transfer, then linking into a polypeptide.
What earns the marks
- Transcription begins when RNA polymerase binds to non-coding DNA located in front of a gene.
- RNA polymerase produces a complementary mRNA strand from the coding DNA of the gene.
- The mRNA attaches to the ribosome.
- Triplets of bases (codons) in the mRNA code for specific amino acids.
- tRNA transfers amino acids to the ribosome.
- The amino acids are linked together to form polypeptides.
Common mistakes and how to put them right
Confusing transcription and translation.
Put it right by placing transcription in the nucleus making mRNA and translation at the ribosome making polypeptide.
Saying tRNA makes mRNA.
Put it right by stating RNA polymerase produces the complementary mRNA strand and tRNA carries amino acids.
Thinking codons are on tRNA rather than mRNA.
Put it right by stating codons are triplets of bases in the mRNA that code for specific amino acids.
Exam tips
- Name the enzyme (RNA polymerase) and the molecule it makes (mRNA) explicitly.
- Keep the six stages in the correct order when describing the process.
- Link each codon to a specific amino acid and state that tRNA transfers it to the ribosome.
Try the lesson
The start of the Topic 3 – Genetics: 3.8B Describe the stages of protein synthesis, including transcription and translation: a RNA polymerase binds to non-coding DNA located in front of a gene b RNA polymerase produces a complementary mRNA strand from the coding DNA of the gene c the attachment of the mRNA to the ribosome d the coding by triplets of bases (codons) in the mRNA for specific amino acids e the transfer of amino acids to the ribosome by tRNA f the linking of amino acids to form polypeptides lesson, made from checked teaching notes for this specification point.
Have a go first
During transcription, which enzyme joins complementary RNA nucleotides to build an mRNA strand from the coding DNA of a gene?
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Test your understanding of Topic 3 – Genetics: 3.8B Describe the stages of protein synthesis, including transcription and translation: a RNA polymerase binds to non-coding DNA located in front of a gene b RNA polymerase produces a complementary mRNA strand from the coding DNA of the gene c the attachment of the mRNA to the ribosome d the coding by triplets of bases (codons) in the mRNA for specific amino acids e the transfer of amino acids to the ribosome by tRNA f the linking of amino acids to form polypeptides
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