IB Biology SL 2.1.11 Sickle-cell anaemia mutation Question Bank
Practise IB Biology SL 2.1.11 by explaining how a DNA base substitution changes haemoglobin and red blood cells.
- Syllabus
- First assessment 2025
- Course
- Biology SL
- Level
- SL
Exam points
- Explain how a base substitution causes sickle-cell anaemia.
- Relate a codon or amino-acid change to altered haemoglobin function.
D1.2.11—Mutations changing protein structure question 1
[Maximum number: 5]
Explain the causes and consequences of sickle-cell anemia.
(point) mutation of gene for hemoglobin;
CTC to CAC / GAG to GTG / substitution of T/thymine with A/adenine;
mRNA copy of gene is GUG instead of GAG;
valine instead of glutamic acid;
(in homozygotes) red blood cells become sickle-shaped;
(in homozygotes) less oxygen carried;
(in homozygotes) red blood cells do not survive long / burst / block blood
vessels/capillaries / circulatory problems may cause pain/organ failure/example of symptom; heterozygotes have malaria resistance;
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