ExpertEasy1 markMultiple Choice
AQA GCSE · Question 01.6 · Inheritance Variation and Evolution
Which scientific term describes the allele N?
Which scientific term describes the allele N?
Answer options:
A.
Dominant
B.
Genetic
C.
Heterozygous
How to approach this question
The allele N is for not having MSUD. We know that a person with genotype Nn does not have MSUD. This means the N allele is expressed over the n allele. Consider the definitions of dominant, genetic, and heterozygous to determine which term fits this description.
Full Answer
A.Dominant✓ Correct
Dominant
An allele is described as dominant if it is always expressed in the phenotype when present. In the genotype Nn, the individual is unaffected by MSUD because the N allele is expressed. Since the N allele masks the effect of the n allele, N is the dominant allele.
Common mistakes
✗ Choosing "Heterozygous". This describes a genotype (Nn), not an individual allele (N).
✗ Choosing "Genetic". This is too general and not a specific term for the type of allele.
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