IB Biology HL 1.3.2 Base substitution and protein consequences Question Bank
Practise IB Biology HL 1.3.2 by analysing base substitutions from DNA sequence through protein to phenotype.
- Syllabus
- First assessment 2025
- Course
- Biology HL
- Level
- HL
Exam points
- Analyse a changed triplet and deduce the resulting codon, amino acid or polypeptide effect.
- Compare silent, missense, nonsense and other possible consequences of a substitution.
- Evaluate the link from molecular change to disease phenotype using the genetic code and evidence.
D1.3.2—Base substitution consequences question 1
[Maximum number: 5]
Outline the effects of a base substitution mutation in the case of sickle-cell anemia.
DNA changes from GAG to GTG / CTC to CAC / mRNA changes from GAG to GUG;
affecting the process of translation / causes different primary structure of polypeptide;
causing glutamic acid to be replaced by valine;
changing the form of hemoglobin;
changes the shape of the red blood cells / red blood cells become sickle shaped;
transport oxygen less efficiently / less oxygen gets to tissues;
sickled cells block capillaries;
muscular pain / severe anemia / slow growth;
correlated with protection against malaria in heterozygotes.
Accept DNA changes from GAA to GTA / CTT to CAT / mRNA changes from GAA to GUA.
Reject Hb sickle shaped.
Allow other appropriate symptom.
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