CAIE A-Level Biology A2 16.2.2 Genetic Diagrams Questions
Construct and interpret genetic diagrams using evidence from each question and mark scheme.
- Syllabus
- 2028–2030
- Course
- Biology 9700
- Level
- A2
Exam points
- Construct and interpret genetic diagrams.
CAIE A-Level Biology A2 16.2.2 Genetic Diagrams Questions question 1
[Maximum number: 3]
A mutation causing coats of mice to be woolly in appearance is in a gene located on chromosome 11. The mutation causes a very shortened polypeptide product. Mice with the woolly coat phenotype have longer fur than mice with normal coats.
The inheritance of the woolly coat characteristic was investigated.
Draw a genetic diagram to show a cross between two heterozygous parents with normal coats.
Use the symbols A and a for the alleles.
parental genotypes
gametes
offspring genotypes
offspring phenotypes
Genetic diagram:
Parental genotypes: Aa x Aa
Gametes: A, a and A, a
Phenotype ratio: 3 normal : 1 woolly.
| Offspring genotype | Offspring phenotype |
|---|---|
| AA | normal |
| Aa | normal |
| Aa | normal |
| aa | woolly |
Marking guidance: award for correct parental genotypes, gametes, and offspring genotypes/phenotypes shown in the genetic diagram.
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