Question

A true-breeding plant with yellow seeds is bred with a true-breeding plant with green seeds. What color seeds will the offspring produce where yellow is the dominant seed color?

A.
all yellow

B.
all green

C.
three-fourths yellow and one-fourth green

D.
three-fourths green and one-fourth yellow

Answer 1

A. all yellow

they will look all yellow but all will be heterozygous

Answer 2

Answer:

The correct answer would be A. all yellow.

Let "Y" be the dominant allele and "y" be the recessive allele of the gene responsible for the color of the seeds.

Dominant allele "Y" codes for the yellow color of the seeds when present in homozygous as well as heterozygous condition whereas recessive allele "y" codes for the green color of the seeds only when present in homozygous condition.

Now, the genotype of a true-breeding plant with yellow seeds would be YY and that of a true-breeding plant with green seeds would be yy.

The gametes formed by yellow seed plant would be Y and gametes formed by green seed plant would be y.

The cross will result in the production of offspring each with genotype Yy.

Hence, all the offspring plants would produce yellow seeds as yellow is a dominant character.