A pair of homologous chromosomes. The first chromosome contains an allele for purple flowers; the other chromosome contains an allele for white flowers in the same locus for the flower-color gene.

Question

Each chromosome in this homologous pair possesses a different allele for flower color. Which statement about this homologous pair of chromosomes is correct?

These homologous chromosomes represent a maternal and a paternal chromosome.
Each of these homologous chromosomes consists of a single chromatid. Therefore, they must come from a haploid cell.
These homologous chromosomes are formed by DNA replication.

Answer 1

The correct statement about the homologous pair of chromosomes you described is:

These homologous chromosomes represent a maternal and a paternal chromosome.

Here's why the other statements are not correct:

1. Each of these homologous chromosomes consists of a single chromatid. Therefore, they must come from a haploid cell. - This statement is generally not correct, as homologous chromosomes can consist of two sister chromatids each after DNA replication (during the S phase of the cell cycle). Only after meiosis does a cell become haploid, but the homologous chromosomes still consist of two chromatids until they are separated during meiosis II.

2. These homologous chromosomes are formed by DNA replication. - This is misleading. Homologous chromosomes are inherited from the parents (one from the mother and one from the father) and do not form from DNA replication of one another. Rather, they are replicated during the S phase but are separate entities that come together in pairs during meiosis.

Thus, the correct understanding is that your homologous chromosomes represent one inherited from the mother (maternal) and one from the father (paternal), with different alleles for flower color.