What happens during the first division of meiosis?

During the first division of meiosis, homologous chromosomes pair up and exchange genetic material before separating into two cells.

In the first division of meiosis, also known as meiosis I, the cell undergoes several stages: prophase I, metaphase I, anaphase I, and telophase I. This process is crucial for sexual reproduction as it ensures genetic diversity among offspring.

In prophase I, the chromosomes condense and become visible. Each chromosome pairs up with its homologous partner to form a structure known as a tetrad, which consists of four chromatids. This pairing is significant as it allows for the exchange of genetic material, a process known as crossing over. Crossing over results in new combinations of genes, contributing to genetic diversity.

During metaphase I, the tetrads align at the cell's equator. Unlike in mitosis, the homologous chromosomes, rather than individual chromatids, align at the metaphase plate. This is a key difference between mitosis and meiosis.

In anaphase I, the homologous chromosomes separate and move towards opposite poles of the cell. It's important to note that the sister chromatids remain attached at their centromeres, unlike in mitosis where they separate.

Finally, during telophase I, the cell divides into two, each with a haploid set of chromosomes. Each chromosome still consists of two sister chromatids. This is followed by cytokinesis, where the cytoplasm divides, resulting in two daughter cells.

In summary, the first division of meiosis involves the pairing of homologous chromosomes, crossing over, alignment at the cell's equator, separation of homologous chromosomes, and cell division. This process is vital for genetic variation and the production of haploid cells for sexual reproduction.