Question

select all that apply
in pea plants, the allele for white flowers is recessive to the allele for purple flowers. in a generation of pea plants, all of the produced flowers were purple. which of
the following are the two best conclusions you can make about the parent plants of this generation?

both parent plants are heterozygous for flower color.
both parent plants were homozygous with purple flowers.
one parent plant had white flowers and the other was heterozygous for flower color.
one parent plant was heterozygous for flower color and the other was homozygous with purple flowers.

Explanation:

1. Let's recall the principles of Mendelian genetics for flower color in pea plants. Let the allele for purple flowers be \( P \) (dominant) and for white flowers be \( p \) (recessive).

• If both parents are heterozygous (\( Pp \times Pp \)), the offspring genotypes would be \( PP \), \( Pp \), \( Pp \), \( pp \). So there would be a 25% chance of white flowers (\( pp \)), which contradicts the fact that all offspring have purple flowers. So the first option is incorrect.
• If both parents are homozygous purple (\( PP \times PP \)), all offspring will be \( PP \) (purple). This is a valid conclusion.
• If one parent has white flowers (\( pp \)) and the other is heterozygous (\( Pp \)), the cross is \( Pp \times pp \). The offspring genotypes would be \( Pp \) and \( pp \), so there would be a 50% chance of white flowers, which is not consistent with all purple offspring. So the third option is incorrect.
• If one parent is heterozygous (\( Pp \)) and the other is homozygous purple (\( PP \)), the cross is \( PP \times Pp \). The offspring genotypes would be \( PP \) and \( Pp \), both of which result in purple flowers. This is also a valid conclusion.

Answer:

B. Both parent plants were homozygous with purple flowers.
D. One parent plant was heterozygous for flower color and the other was homozygous with purple flowers.