Rebecca Davenport BIOL 1406 BW1 10 10 16 Ch 11 Blueprint Cell communication 6 questions on exam 1 Cellular messaginga Cells can signal to each other and interpret the signals they receive from other cells and the environment b Signals are most often chemicals c Signal transduction pathway convert signals received at a cell s surface into cellular responses d Local and long distance signaling i Local Signaling1 Cells in multicellular organism communicate via signaling molecules 2 Animal cells may communicate via Direct contact a Cell junctions directly connect the cytoplasm of adjacent cells b Cell Cell recognition contact between cell surface molecules 3 In many other cases animal cells communicate using secreted massager molecules that travel only short distances a Paracrine signaling a cell secretes molecules of a local regulator b Synaptic signaling a neurotransmitter is released in response to an electric signal ii Long Distance signaling1 In long distance signaling plants and animals use chemicals called hormones 2 Hormonal signaling in animals is called endocrine signaling a Specialized cells release hormones which travel to target cells via the circulatory system 3 The ability of a cell to respond to a signal depends on whether or not it has a receptor specific to that signal iii iv e 3 stages of cell signaling i Reception the target cells detects a signaling molecule that binds to a receptor protein on the cell surface causing it to change shape ii Transduction the binding of signaling molecule alters the receptor and initiates a signal transduction pathway 1 Transduction often occurs in a series of steps iii Response the transduced signal triggers a specific response in target cell f iv Receptorsi Receptors that bind signal molecules are found on the plasma membrane or inside the target cell in the cytosol or nucleus ii Most water soluble signal molecules bind to specific sites on receptor proteins that span the plasma membrane iii Intracellular receptor proteins are found in the cytoplasm or nucleus of target cells 1 Small or hydrophobic chemical messengers can readily cross the membrane and activate receptors
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