Signals and feedback - Signals and feedback Living cells...

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Signals and feedback Living cells can be viewed as signal processors . That is not all they are, but it is a useful perspective in the current context. The cells receive signals from the environment in the form of specific molecules (e.g. hormones, transmitter substances), nutrient levels (e.g. glucose, lipids) or stresses (e.g. osmotic pressure, poisons, heat, cold). The cells also produce signals internally , e.g. in the cell cycle, where such events as DNA damage or failures in chromosome duplication generate signals that stop cell division from occuring, and may also start repair processes or to begin the cell death program (apoptosis). The various signals and the machinery that processes them form a regulatory network. The purpose of the network is to control the life processes so that the organism can grow, survive and multiply in a constantly changing and challenging environment. Regulation is the key term here. The appropriate systems must be started up, or shut down, as the environment changes. If suddenly glucose becomes
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Signals and feedback - Signals and feedback Living cells...

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