Chapter 11 ? Cell Communication Overview: The Cellular Internet The trillions of cells in a multicellular organism must communicate with each other to coordinate their activities. There are networks of communication between cells ? can be very complicated There are Universal Mechanisms of cellular regulation (and communication) ? this is further evidence that all life is related (evolutionarily). 11.1 External Signals are converted to responses within the cell What do the cells say to each other? Evolution of Cell Signaling: One thing they talk about is sex/reproduction. Example: Yeast cells: (figure 11.2) There are two genders or mating types ? ?a? and ?alpha? Type ?a? cells secrete ?a? factor which can bind on specific receptors on the ?alpha? cell