Q. If a trait is controlled by a single gene with two alleles, what is the maximum number of different genotypes possible in a population?
A.1
B.2
C.3
D.4
Solution
For a single gene with two alleles, the maximum number of different genotypes possible is 3: homozygous dominant, heterozygous, and homozygous recessive.
Q. In a cross between two pea plants, one with round seeds (R) and one with wrinkled seeds (r), what is the phenotype of the F1 generation if round is dominant?
A.Round
B.Wrinkled
C.Both
D.Neither
Solution
The phenotype of the F1 generation will be round seeds since round (R) is dominant over wrinkled (r).
Q. In a test cross, an individual with an unknown genotype is crossed with a homozygous recessive individual. What is the purpose of this cross?
A.To determine the dominant allele
B.To determine the recessive allele
C.To determine the genotype of the unknown
D.To determine the phenotype of the offspring
Solution
The purpose of a test cross is to determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive individual.
Correct Answer: C — To determine the genotype of the unknown
