How are homologous chromosomes different from sister chromatids?

• A. Homologous chromosomes are found only in prokaryotic cells, while sister chromatids are found in eukaryotic cells.
• B. Homologous chromosomes are pairs of chromosomes containing the same genes but may have different alleles, while sister chromatids are identical copies of a single chromosome.
• C. Homologous chromosomes are identical copies of a single chromosome, while sister chromatids contain different genes.
• D. Homologous chromosomes are formed during mitosis, while sister chromatids are formed during meiosis.

Answer: (B)

Verified step by step guidance

1. Understand the basic definitions: Homologous chromosomes are pairs of chromosomes in a diploid organism that have the same genes at the same loci but may have different alleles. Sister chromatids are identical copies of a single chromosome that are connected by a centromere.
2. Recognize the context in which each is found: Homologous chromosomes are present in diploid cells, which are typical of eukaryotic organisms. Sister chromatids are formed during the process of DNA replication in both mitosis and meiosis.
3. Differentiate based on genetic content: Homologous chromosomes can have different alleles for the same genes, meaning they are not identical. In contrast, sister chromatids are exact copies of each other, having the same alleles.
4. Identify the process of formation: Homologous chromosomes are inherited from each parent, one from the mother and one from the father. Sister chromatids are formed during the S phase of the cell cycle when DNA is replicated.
5. Clarify the role in cell division: During meiosis, homologous chromosomes pair up and can exchange genetic material through crossing over, while sister chromatids are separated during both mitosis and meiosis II.