MDG 10

Physically, what are different alleles?

1. Different alleles are different DNA sequences found at the same locus on homologous chromosomes.

2. Different alleles are different particles found in gametes.

3. None of the choices is correct.

• 1. Different alleles are different DNA sequences found at the same locus on sister chromatids.

• 1. Different alleles are different phenotypes for a particular character.

• 1. Different alleles are different DNA sequences found at the same locus on homologous chromosomes.

• 1. Different alleles are different particles found in gametes.

• 1. None of the choices is correct.

Does dominant mean the most common trait?

• Yes

• No

In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the same phenotype as a plant with the genotype __________.

• 1. Aabbcc

• 1. AaBBcc

• 1. AABBCc

• 1. aabbcc

• 1. None of the choices is correct.

Assume tall (T) is completely dominant to dwarf (t) in a certain species of plant. If a homozygous dominant individual is crossed with a homozygous dwarf, the offspring will __________.

• 1. all be intermediate in height with a genotypes of Tt

• 1. be 1/2 tall and 1/2 dwarf because the genotype is Tt and tt

• 1. all be short

• 1. be 3/4 tall and 1/4 dwarf because of genotypes Tt and tt

• 1. all be tall with a genotypes of Tt

Answer explanation

Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt. A tall plant is mated with a short plant. Which outcome would indicate that the tall parent plant was heterozygous?

• 1. All of the offspring are tall.

• 1. The ratio of tall offspring to short offspring is 3:1.

• 1. There is not enough information to answer the question.

• 1. All of the offspring are short.

• 1. The ratio of tall offspring to short offspring is 1:1.

Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring from the cross PpRr x PpRr will have white flowers and wrinkled seeds?

• 0

• 1/16

• 1/4

• 1/2

• 3/4