DP Biology (first assessment 2025)

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Question 22M.2.SL.TZ2.6a

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Date May 2022 Marks available [Maximum mark: 5] Reference code 22M.2.SL.TZ2.6a
Level SL Paper 2 Time zone TZ2
Command term Outline Question number a Adapted from N/A
a.
[Maximum mark: 5]
22M.2.SL.TZ2.6a
(a)

Outline how a protein is made in a cell by the process of translation.

[5]

Markscheme
  1. translation occurs on ribosomes when proteins/polypeptides are synthesized;
  2. amino acid sequence of a protein is determined by the mRNA;
  3. mRNA is determined by the order of bases of DNA/order of bases sequence in a gene;
  4. codons (of 3 bases) on mRNA correspond to one amino acid in a polypeptide;
  5. codons are on mRNA and anticodons on tRNA;
  6. mRNA binds to ribosome/(during initiation) small ribosomal subunit binds to the start of the mRNA sequence;
  7. tRNA transfers an amino acid to large ribosomal subunit/to the ribosome;
  8. reference to start or stop codon;
  9. tRNA moves to the next mRNA codon to continue the process, creating an amino acid chain;
  10. peptide bond formed between amino acids
  11. translation/order of amino acids depends on complementary base pairing between codons and anticodons;
Examiners report

Well prepared candidates were able to clearly explain the production of a protein by translation. Weak candidates usually scored a few points. Many started with a very detailed description of transcription, which was not necessary and put them in danger of losing the quality mark.

Syllabus sections