Cell Communication and Cell Cycle

Seven topics on how cells talk to each other and how they divide. Cell communication and why a cell responds only if it has the right receptor — and how the distance between cells sets the mechanism, an introduction to signal transduction where receptors sit on the membrane or inside the cell and the signal triggers a relay rather than acting directly, the transduction cascade itself and how it amplifies one signal into many downstream molecules, the changes a mutation or chemical can make to a pathway — turning it off, locking it on, or altering the response, feedback that is stabilizing (negative) or self-amplifying (positive), the cell cycle where cells spend most of their time in interphase and mitosis plus cytokinesis divides them into identical cells, and the regulation of that cycle by checkpoints and rising-and-falling cyclin-CDK activity — with cancer as a failure of that control.