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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>DNA responds to signals from outside the cell :: DNA from the Beginning</title> <meta name="description" content="Signal transduction is cell communication that involves a series of molecular transformations." /> <link rel="preload" as="style" src="/css/main.css"> <link rel="preload" as="script" src="/js/swfobject.js"> <link rel="preload" as="script" src="/js/prototype-1.6.1.js"> <link href="/css/main.css" rel="stylesheet" type="text/css" /> <link href='https://fonts.googleapis.com/css?family=Droid+Serif' rel='stylesheet' type='text/css'/> <link href='https://fonts.googleapis.com/css?family=Droid+Sans' rel='stylesheet' type='text/css'/> <script type="text/javascript" src="/js/swfobject.js"></script> <script type="text/javascript" src="/js/prototype-1.6.1.js"></script> </head> <body> <div id="container"> <div id="content"> <div id="header"> <div class="rollover-home"> <a href="/" class="rollover-home" title="DNA from the Beginning Home"><span class="displace">Home</span></a> </div> </div>  <div id="content-container"> <h1><span> Concept 35</span> DNA responds to signals from outside the cell.</h1> <div id="nav"> <ul> <li class="menu1"><a href="index.html" title="CONCEPT" ><span class="displace">CONCEPT</span></a></li> <li class="menu2"><a href="animation.html" title="ANIMATION"><span class="displace">ANIMATION</span></a></li> <li class="menu3"><a href="gallery.html" title="GALLERY"><span class="displace">GALLERY</span></a></li> <li class="menu4"><a href="av.html" title="VIDEO"><span class="displace">VIDEO</span></a></li> <li class="menu5"><a href="bio.html" title="BIO"><span class="displace">BIO</span></a></li> <li class="menu6"><a href="problem.html" title="PROBLEM"><span class="displace">PROBLEM</span></a></li> <li class="menu7"><a href="links.html" title="LINKS" ><span class="displace">LINKS</span></a></li> </ul> <br class="clearfloat" /> </div> <div id="concept"> <img src="/images/35/concept35.jpg" class="concept-image" alt="DNA responds to signals from outside the cell." /> <p>Growth and development require that cells communicate with each other and react to signals that come from other parts of the body. Notably, hormones released by various glands travel throughout the body to stimulate the growth of certain cell types. Cells capable of being stimulated by a particular hormone possess a specific receptor anchored in the cell membrane. The binding of a hormone to its receptor initiates a series of molecular transformations, called signal transduction, that relay the growth signal through the cell. </p> <p>First, the receptor transduces the signal through the cell membrane to the internal membrane surface, where it activates protein "messengers." These messengers are part of and initiate a cascade of chemical reactions, often involving the addition of phosphate groups. This is the signal that passes through the cytoplasm and into the nucleus. In the final step of signal transduction, DNA binding proteins attach to regulatory sequences and start DNA replication or transcription.</p> </div> </div> <br class="clearfloat" /> <div id="footer"> <ul> <li><a href="/">Home</a></li> <li><a href="/sitemap.html">Site Map</a></li> <li><a href="/scientists.html">Scientists</a></li> <li><a href="/glossary.html">Glossary</a></li> <li><a href="/feedback.html">Feedback</a></li> <li><a href="/awards.html">Awards</a></li> <li><a href="/credits.html">Credits</a></li> <li><a href="http://blogs.dnalc.org/dnaftb/" style="background-image:none;">Blog</a></li> </ul> <p> Funded by <a href="http://macyfoundation.org">The Josiah Macy, Jr. Foundation</a><br /> © 2002 - 2011, <a href="http://www.dnalc.org/"> DNA Learning Center</a>, <a href="https://www.cshl.edu/">Cold Spring Harbor Laboratory</a>. All rights reserved. </p> </div>  </div> <div id="sidebar"> <div id="search" > <form method="get" action="/search"> <div class="fieldHolder1"> <input type="search" id="q" name="q" placeholder="Search" onclick="this.value=''" value="" /> <img style="background-color:#9C0;" src="/images/general/search_icon.jpg" alt="Search" onclick="document.forms[0].submit()" /> </div> </form> </div>  <div id="sidebar"> <ul class="menu-side" > <li class="section1"><a href="/1/index.html" title="Classical Genetics"><span class="displace">CLASSICAL GENETICS</span></a></li> <li class="section2" style="margin-bottom: 3px;"><a href="/15/index.html" title="Molecules of Genetics"><span class="displace">MOLECULES OF GENETICS</span></a></li>  </ul> <ul class="sections-side sections-side3a" style="padding-top: 56px;" > <li ><a href="/29/"><img src="/images/thumbnails/29-thumb-sm.png" alt="29." />DNA is packaged in a chromosome.</a></li> <li ><a href="/30/"><img src="/images/thumbnails/30-thumb-sm.png" alt="30." />Higher cells incorporate an ancient chromosome.</a></li> <li ><a href="/31/"><img src="/images/thumbnails/31-thumb-sm.png" alt="31." />Some DNA does not encode protein.</a></li> <li ><a href="/32/"><img src="/images/thumbnails/32-thumb-sm.png" alt="32." />Some DNA can jump.</a></li> <li ><a href="/33/"><img src="/images/thumbnails/33-thumb-sm.png" alt="33." />Genes can be turned on and off.</a></li> <li ><a href="/34/"><img src="/images/thumbnails/34-thumb-sm.png" alt="34." />Genes can be moved between species.</a></li> <li ><a class="concept-highlight" href="/35/"><img src="/images/thumbnails/35-thumb-sm.png" alt="35." />DNA responds to signals from outside the cell.</a></li> <li ><a href="/36/"><img src="/images/thumbnails/36-thumb-sm.png" alt="36." />Different genes are active in different kinds of cells.</a></li> <li ><a href="/37/"><img src="/images/thumbnails/37-thumb-sm.png" alt="37." />Master genes control basic body plans.</a></li> <li ><a href="/38/"><img src="/images/thumbnails/38-thumb-sm.png" alt="38." />Development balances cell growth and death.</a></li> <li ><a href="/39/"><img src="/images/thumbnails/39-thumb-sm.png" alt="39." />A genome is an entire set of genes.</a></li> <li ><a href="/40/"><img src="/images/thumbnails/40-thumb-sm.png" alt="40." />Living things share common genes.</a></li> <li style="border-bottom: 1px solid #669;"><a href="/41/"><img src="/images/thumbnails/41-thumb-sm.png" alt="41." />DNA is only the beginning for understanding the human genome.</a></li> </ul> </div>  </div>  <br class="clearfloat" /> </div>  <script type="text/javascript"> Event.observe(window, 'load', function() { var uri = '/35/index.html'; uri = uri.replace(/-\d/,''); $('nav').down().descendants().each(function(s) { if (s.nodeName == 'A') { if (s.href.match(uri)) { s.addClassName('current'); throw $break; } } }); }); </script> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-1818773-10']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = 'https://www.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script>  <script async src="https://www.googletagmanager.com/gtag/js?id=G-K6EHFCRJBP"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-K6EHFCRJBP'); </script> </body> </html>