Final answer:
Yeasts are eukaryotic organisms that can autonomously initiate their cell cycle, simplifying the study of cell signaling cascades. They use a signaling molecule called mating factor to communicate for mating purposes, which is separate from the signaling process that regulates cell division.
Step-by-step explanation:
Yeasts are eukaryotic organisms and belong to the fungi kingdom, which means they bypass the need for cell-cell communication to initiate cell division, a process that is typically regulated in multicellular organisms. Instead of requiring signals from other cells to commence division, yeasts can autonomously start their cell cycle without the START phase that is necessary for cell communication in higher eukaryotes. This characteristic of yeasts simplifies the study of their cell signaling cascades, which, although analogous to human signaling processes, are far less complex, making yeasts an ideal model system for research. Budding yeasts reproduce both asexually by budding and through a form of sexual reproduction by combining two haploid cells to create a diploid cell. They initiate mating by secreting a signaling molecule called mating factor, which binds to receptors on nearby yeasts, activating a signaling cascade that is necessary for mating but distinct from the cell division signaling.