How do yeast sometimes reproduce sexually?

Answer 1

• Only haploid yeast cells are able to conduct sexual reproduction. When they do, the haploid cells are usually not the same gender. Before joining with the opposite type of haploid yeast cell, each cell undergoes a process called shmooing in which it becomes longer and thinner in preparation for the joining. The shmooing cells then fuse and join their nuclei together to create a diploid. The new diploid then begins to bud and form a colony of diploid yeast cells.

• Sexual reproduction continues with the diploid cell returning to a haploid state when the environmental conditions become hostile. Cells that already exist as haploids tend to die off when environmental conditions are unfavorable, but diploid cells undergo meiosis and subsequently divide into four daughter haploid spores in poor environmental conditions. Spores are inert cells that are able to tolerate adverse conditions much better than active cells. When the environmental conditions become favorable again, the spores begin to resume normal life cycle activities, either continuing to exist as haploids or joining with other haploids to create new diploid colonies.