AP Biology : Understanding Dominant and Recessive Traits

Study concepts, example questions & explanations for AP Biology

varsity tutors app store varsity tutors android store

Example Questions

1 3 Next →

Example Question #21 : Understanding Dominant And Recessive Traits

Dominant traits are __________.

Possible Answers:

always more beneficial than recessive ones

usually more deleterious than recessive alleles

None of the other answers

likely to show phenotypically 75% of the time no matter what trait it is

Correct answer:

None of the other answers

Explanation:

Dominant alleles are neither better, nor worse than recessive alleles. They are simply expressed in the phenotype of a heterozygous pair. Several deleterious, and even deadly disorders like Huntington's disease, are inherited via an autosomal dominant pattern.

Note that the frequency of an allele or genotype in a population must be determined experimentally, and can be linked to environmental influences, autosomal versus sex-linked patterns, and numerous other factors.

Example Question #22 : Understanding Dominant And Recessive Traits

Which is true of a pea plant with rounded pods and alleles Rr?

Possible Answers:

The genotype is Rr and the phenotype is rounded pods

The phenotype is Rr and the genotype is rounded pods

The F2 generation will only have rounded pods

The F1 generation will only have rounded pods

Correct answer:

The genotype is Rr and the phenotype is rounded pods

Explanation:

The genotype describes the genetic makeup or alleles of the individual, while the phenotype describes the physical characteristic of the individual.

Example Question #23 : Understanding Dominant And Recessive Traits

In a cross between two organisms, the offspring are referred to as the ___ generation. 

Possible Answers:

F2

O1

F1

P

Correct answer:

F1

Explanation:

The parent generation refers to the generation in which the two organisms are crossed; the F1 generation is the first filial generation, or the offspring produced from the cross; the F2 generation is the second filial generation, or the offspring produced from a cross between two F1 organisms.

1 3 Next →
Learning Tools by Varsity Tutors