BIOL 2100 Lecture Notes - Lecture 11: Mating Of Yeast, Quorum Sensing, Signal Transduction
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11. 1: external signals are converted to responses within the cell. Evolution of cell signaling: there are two sexes, or mating types called a and . Each type secretes a specific factor that binds to receptors only on the other type of cell. New a/ cell- the nucleus of the fused cell includes all the genes from the a and cells. This occurs in a series of steps called a signal transduction pathway. Scientists think that cell signaling mechanisms first evolved in ancient prokaryotes and single-celled eukaryotes and then were adopted for new uses by their multicellular descendants. Bacteria has quorum sensing- allows bacterial populations to coordinate their behaviors in activities that require a given number of cells acting synchronously; sensing concentration of such signaling molecules allows bacteria to monitor the local density of cells. Example- formation of a biofilm- an aggregation of bacterial cells adhered to a surface.