In a typical diploid somatic cell undergoing mitosis, which statement best describes the presence and behavior of homologous chromosomes?

• A. Homologous chromosomes are present but they do not pair (synapse) or undergo crossing over during mitosis.
• B. Homologous chromosomes separate from each other at anaphase of mitosis, while sister chromatids remain together.
• C. Homologous chromosomes are absent because mitosis occurs only in haploid cells.
• D. Homologous chromosomes pair as bivalents and undergo crossing over during prophase of mitosis.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the nature of homologous chromosomes in diploid somatic cells. Homologous chromosomes are pairs of chromosomes, one inherited from each parent, that have the same genes but may have different alleles.
2. Step 2: Recall the process of mitosis, which is a type of cell division that results in two genetically identical daughter cells, maintaining the diploid chromosome number.
3. Step 3: Recognize that during mitosis, homologous chromosomes do not pair up or synapse as they do in meiosis. Instead, each chromosome replicates to form sister chromatids, which remain attached.
4. Step 4: Note that during anaphase of mitosis, sister chromatids separate and move to opposite poles, while homologous chromosomes do not pair or undergo crossing over.
5. Step 5: Conclude that the correct description is that homologous chromosomes are present in mitosis but do not pair or undergo crossing over; they separate independently during mitosis.