Yeast, a type of single-celled fungi, has two main stages in its life cycle: the haploid stage and the diploid stage.
- Haploid stage: During the haploid stage, yeast cells have a single set of chromosomes. The haploid stage begins when two haploid cells (often referred to as “mating types”) fuse together to form a single cell with two nuclei.
- Diploid stage: The diploid stage begins when the two nuclei in the fused cell combine, resulting in a diploid cell with two sets of chromosomes. This stage is characterized by cell growth and division, resulting in a colony of genetically identical diploid cells.
Under certain conditions, such as nutrient deprivation or exposure to high temperatures, yeast cells can undergo a process called sporulation. During sporulation, diploid cells undergo meiosis, resulting in the formation of four haploid spores. These spores can then germinate to form new haploid cells, completing the yeast life cycle.