How can a cell end up with an incorrect number of chromosomes during meiosis?

• A. By undergoing mitosis instead of meiosis
• B. By replicating its DNA twice before cell division
• C. Through nondisjunction, where chromosomes fail to separate properly
• D. Through crossing over, which exchanges genetic material between homologous chromosomes

Answer: (C)

Verified step by step guidance

1. Understand the process of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the production of gametes. It involves two rounds of division: meiosis I and meiosis II.
2. Learn about nondisjunction: Nondisjunction is an error in meiosis where homologous chromosomes or sister chromatids fail to separate properly during anaphase. This can lead to gametes with an abnormal number of chromosomes.
3. Explore the consequences of nondisjunction: If nondisjunction occurs, it can result in conditions such as trisomy (an extra chromosome) or monosomy (a missing chromosome) in the offspring.
4. Differentiate between meiosis and mitosis: Mitosis is a process of cell division that results in two identical daughter cells, maintaining the same chromosome number. Meiosis, on the other hand, reduces the chromosome number by half.
5. Understand the role of crossing over: Crossing over occurs during prophase I of meiosis and involves the exchange of genetic material between homologous chromosomes. While it increases genetic diversity, it does not lead to an incorrect number of chromosomes.