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Article: Signaling and Signal Transduction
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- Biology
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CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Signaling and Signal Transduction
All cells are able to sense and respond to substances present in their external environments. For example,
motile
bacteria will move toward a source of sugar but away from a toxic chemical such as phenol. Cells are not only able to sense chemical substances in their environments, but also such things as heat and cold. Sudden exposure to elevated temperatures results in the synthesis of a set of
proteins
that protect the cell from heat damage.
The ability to respond to external stimuli enhances a cell's chance of survival, but in addition, especially in multicellular organisms, responding to external stimuli can be part of a cell's moment-to-moment ...