CAIE A-Level Biology A2 16.2.4 Genes Proteins and Phenotype Questions
Explain how genes influence proteins and phenotype using evidence from each question and mark scheme.
- Syllabus
- 2028–2030
- Course
- Biology 9700
- Level
- A2
Exam points
- Explain how genes influence proteins and phenotype.
CAIE A-Level Biology A2 16.2.4 Genes Proteins and Phenotype Questions question 1
[Maximum number: 5]
Genes have a role in determining the overall phenotype of an organism.
Using haemophilia as an example, explain the relationship between a gene, a protein and a phenotype.
Any five from:
1. a gene codes for a protein which determines the phenotype ;
2. F8 gene ;
3. located on X chromosome / sex-linked ;
4. reference to recessive allele ;
5. non-functioning factor VIII protein, or less factor VIII protein, or no factor VIII protein ;
6. so blood does not clot quickly enough / excessive bleeding occurs after an injury ;
7. link the phenotype to the genotype, e.g.:
- XFXF = normal female ;
- XFXf = normal female ;
- XfXf = affected female ;
- XFY = normal male ;
- XfY = affected male ;
8. AVP, e.g. prevents activation of thrombin / fibrinogen not converted to fibrin / mostly males affected / different mutations cause a range of severity of haemophilia.
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