Edexcel A Level Biology A (Salters-Nuffield)
Edexcel A Level Biology A (Salters-Nuffield) Topic 2: DNA and Protein Synthesis Exam Questions
Free Edexcel A Level Biology A (Salters-Nuffield) exam questions on Topic 2: DNA and Protein Synthesis, with mark schemes. Covers DNA and RNA structure, semi-conservative replication, the genetic code, transcription and translation.
Topic 2: DNA and Protein Synthesis exam questions
These packs of real past exam questions cover the whole of Topic 2: Genes and Health, including Topic 2: DNA and Protein Synthesis. Work through every question on this sub-topic, then mark your answers against the mark scheme.
StemUp mark scheme flashcards
Edexcel A Level Biology A (SNAB) 9BN0 Flashcards (Anki & Quizlet)
Every answer is written in mark scheme wording, so you learn exactly what examiners give marks for. Use them on Anki or Quizlet, then test yourself with the questions on this page.
From £10.99View flashcards
About Edexcel A Level Biology A (Salters-Nuffield) Topic 2: DNA and Protein Synthesis
This part of Topic 2 explains how genes code for proteins. Questions test the stages of protein synthesis and the Meselson-Stahl experiment.
What you need to know
- Nucleic acids DNA is a double helix of nucleotides with complementary base pairing; RNA is single-stranded with uracil.
- Replication Semi-conservative replication using DNA helicase and DNA polymerase, supported by Meselson and Stahl.
- The genetic code A non-overlapping, degenerate triplet code.
- Protein synthesis Transcription makes mRNA in the nucleus; translation on ribosomes uses tRNA anticodons to build the polypeptide.
Common mistakes in Topic 2: DNA and Protein Synthesis
- Saying DNA polymerase unwinds DNA (helicase does).
- Mixing up codons and anticodons.
- Forgetting uracil replaces thymine in RNA.
Try three Topic 2: DNA and Protein Synthesis exam-style questions
1. Explain what is meant by semi-conservative replication. (2 marks)
Show the mark scheme answer
Each new DNA molecule contains one original strand (1) and one newly synthesised strand (1).
2. Describe the role of tRNA in translation. (3 marks)
Show the mark scheme answer
tRNA carries a specific amino acid (1); its anticodon pairs with the complementary codon on mRNA (1), bringing amino acids in the correct order to the ribosome (1).
3. Explain why the genetic code is described as degenerate. (1 mark)
Show the mark scheme answer
Most amino acids are coded for by more than one triplet.
Topic 2: DNA and Protein Synthesis FAQs
What does this part of SNAB Topic 2 cover?
DNA and RNA structure, replication, the genetic code and protein synthesis.
Do I need the Meselson-Stahl experiment?
Yes, to explain the evidence for semi-conservative replication.
How is it linked to cystic fibrosis?
A mutation in the CFTR gene changes the protein produced, causing CF.
Revise this topic with flashcards: Edexcel A Level Biology A (SNAB) 9BN0 Flashcards, with mark scheme answers for Anki and Quizlet.
