Mitosis is the process of cell division that ensures each daughter cell receives an identical set of chromosomes. To understand how haploid and diploid numbers change during mitosis, let’s explore what haploid and diploid mean:
- Diploid (2n): This refers to a cell that contains two complete sets of chromosomes, one from each parent. In our case, starting with 4 chromosomes means the diploid number is 4.
- Haploid (n): A haploid cell has only one complete set of chromosomes. For our example, starting with a diploid number of 4, the haploid number would be 2.
Now, let’s look at each stage of mitosis:
- Interphase: Before mitosis begins, the cell is in interphase. It prepares for division, and the chromosomes are duplicated. Thus, at the end of interphase, you still have the diploid number of 4, but now you have 8 sister chromatids (since each chromosome has been replicated).
- Prophase: The chromosomes condense and become visible. The diploid number remains 4, but again you have 8 chromatids. The haploid number remains 2.
- Metaphase: Chromosomes align in the center of the cell. The diploid number is still 4 and haploid is still 2, with 8 chromatids present.
- Anaphase: The sister chromatids are pulled apart to opposite poles. Even though they separate, the diploid count remains 4 (in terms of total sets) and the haploid number is still 2 until cytokinesis occurs.
- Telophase: The chromatids reach the poles and begin to decondense. At this point, the cell is preparing to split. The diploid number is still treated as 4 until the cell ultimately divides.
- Cytokinesis: This is the final step where the cell physically divides into two daughter cells. Each daughter cell inherits a diploid number of 4 and a haploid number of 2 before undergoing a new interphase.
In summary, throughout the stages of mitosis, the haploid number remains 2, and the diploid number remains 4 until cytokinesis. After division, the two daughter cells will both possess a diploid number of 4 chromosomes as they enter a new interphase.