BIO120H1 Chapter Notes - Chapter 11: Caspase, Diglyceride, Endoplasmic Reticulum
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BIO120H1 Full Course Notes
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Document Summary
Cell-to-cell communication is essential for both multicellular and unicellular organisms. Biologists have discovered some universal mechanisms of cellular regulation. Cells most often communicate with each other via chemical signals. For example, the fight-or-flight response is triggered by a signaling molecule called epinephrine. Concept 11. 1: external signals are converted to responses within the cell: microbes provide a glimpse of the role of cell signaling in the evolution of life. The yeast, saccharomyces cerevisiae, has two mating types, a and . Cells of different mating types locate each other via secreted factors specific to each type. A signal transduction pathway is a series of steps by which a signal on a cell"s surface is converted into a specific cellular response. Signal transduction pathways convert signals on a cell"s surface into cellular responses. Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes. The concentration of signaling molecules allows bacteria to sense local population density.
