Question

A pea plant with purple flowers is heterozygous for flower colour. Its genotype is Pp. The P and p alleles in the pea plant's cells are located:
A) next to each other on the same chromosome.
B) at the same location on homologous chromosomes.
C) on the X and Y chromosomes.
D) some distance apart on the same chromosome.

Answer 1

Hint: Alleles are various gene forms that affect how a trait is expressed phenotypically. Multiple alleles refer to a gene's presence at the same locus with more than two alleles controlling a single type of phenotypic trait. The P and p alleles are then found in the same spot on homologous chromosomes in the pea plant's cells.

Complete Step by Step Answer:
An allele is referred to as a particular gene version. For instance, the gene that determines the colour of a flower will have many alleles that result in various hues. We refer to the specific location of a gene on a chromosome as the locus of the corresponding gene.
The term "homologous chromosomal pair" refers to a pair of chromosomes that are identical in length, structure (centromere position), and gene content.

The information provided in the questions suggests that the P and p alleles in the pea plant's cells are situated at the relevant location on homologous chromosomes based on the definitions of allele and homologous chromosomes.
These alleles are not possible to have on chromosomes X and Y. There is no homology between chromosomes X and Y. They each carry entirely different gene pools.
Hence, option B is the correct answer.

Note: There are three genotypes: PP, homozygous dominant, and heterozygous dominant (Pp) (homozygous recessive). The first two are identical to the third despite having different genotypes since they have the same phenotype (purple) (white).