← all pages
2.02:_Hydrocarbons
view live ↗
<p class="lt-bio-3780" style="background-color: unset;">Hydrocarbons are organic molecules that consist exclusively, or primarily, of carbon and hydrogen atoms. They come in two flavors: (1) aliphatic hydrocarbons that consist of linear chains of carbon atoms and (2) aromatic hydrocarbons that which consist of closed rings of carbon atoms.</p> <span id="Aliphatic_Hydrocarbons"></span><span id="Aliphatic_Hydrocarbons"></span><h2 style="background-color: unset;" class="lt-bio-3780">Aliphatic Hydrocarbons</h2> <p class="mt-indent-1 lt-bio-3780" style="background-color: unset;"><img style="width: 186px; height: 95px;" class="internal" alt="Diagram of methane and ethane molecules. Methane has one carbon atom bonded to four hydrogen atoms. Ethane has two carbon atoms bonded to six hydrogen atoms, three on each carbon." loading="lazy" width="186px" height="95px" src="https://bio.libretexts.org/@api/deki/files/5117/Methane_Ethane.gif?revision=1&size=bestfit&width=186&height=95" /> <img style="width: 363px; height: 312px;" class="internal" alt="Diagram of a triglyceride molecule, specifically tristearin, showing carbon chains with hydrogen and oxygen atoms in a vertical arrangement, labeled tristearin at the bottom." loading="lazy" width="363px" height="312px" src="https://bio.libretexts.org/@api/deki/files/5118/Tristearin.gif?revision=1&size=bestfit&width=363&height=312" /></p> <p class="lt-bio-3780" style="background-color: unset;">The simplest is methane, CH<sub><font size="2">4</font></sub>. Next is ethane, C<sub><font size="2">2</font></sub>H<sub><font size="2">6</font></sub>.</p> <p class="lt-bio-3780" style="background-color: unset;">The fatty acids in fats are aliphatic hydrocarbons. If a chain holds all the hydrogen atoms it can, the molecule is said to be <strong>saturated</strong>. The fatty acids in <strong>tristearin</strong> are all saturated.</p> <p class="lt-bio-3780" style="background-color: unset;">If two adjacent carbon atoms each lose a hydrogen atom, a double bond forms between them. Such a molecule is said to be <strong>unsaturated</strong>.</p> <p class="lt-bio-3780" style="background-color: unset;">Example : Ethylene <strong>H<sub><font size="3">2</font></sub>C=CH<sub><font size="3">2</font></sub></strong></p> <p class="lt-bio-3780" style="background-color: unset;">The fatty acids in trilinolein and linolenic acid are examples of unsaturated fatty acids</p> <p class="mt-align-center lt-bio-3780" style="background-color: unset;"><img class="internal" alt="Diagram of linolenic acid, an omega-3 fatty acid. The chain has 18 carbon atoms with double bonds shown. The omega carbon is highlighted in blue." loading="lazy" src="https://bio.libretexts.org/@api/deki/files/5119/linolenic.gif?revision=1" width="366" height="123" /></p> <span id="Aromatic_Hydrocarbons"></span><span id="Aromatic_Hydrocarbons"></span><h2 style="background-color: unset;" class="lt-bio-3780">Aromatic Hydrocarbons</h2> <p class="lt-bio-3780" style="background-color: unset;">The building block of aromatic hydrocarbons is the benzene ring. The arrangement of atoms is shown on the left. The version in the center is often used to simplify diagrams of molecular structures. The three double bonds are not restricted to the positions shown but are free to pass around the ring. This is sometimes indicated by drawing the benzene ring as it is on the far right.</p> <p class="mt-align-center lt-bio-3780" style="background-color: unset;"><img height="177" width="341" class="internal" alt="Diagram showing benzene: (1) detailed structural formula, (2) simplified hexagon with alternating double bonds, and (3) hexagon with a circle inside, representing delocalized electrons." loading="lazy" src="https://bio.libretexts.org/@api/deki/files/5120/benzene.gif?revision=1" /></p> <p class="lt-bio-3780" style="background-color: unset;">Some examples of biological molecules that incorporate the benzene ring:</p> <ul> <li class="lt-bio-3780" style="background-color: unset;">the amino acids tyrosine and phenylalanine</li> <li class="lt-bio-3780" style="background-color: unset;">cholesterol and its various derivatives, such as the sex hormones: estrogens and testosterone</li> <li class="lt-bio-3780" style="background-color: unset;">the herbicide, 2,4-D</li> </ul> <p class="lt-bio-3780" style="background-color: unset;"><img class="internal" alt="Chemical structure of vitamin B12, featuring a long chain of linked carbon and hydrogen atoms with additional nitrogen and oxygen atoms, on a blue background." loading="lazy" src="https://bio.libretexts.org/@api/deki/files/5121/carotenoid.gif?revision=1" /></p> <p class="lt-bio-3780" style="background-color: unset;">The carotenoid, <strong>beta-carotene</strong>, is a hydrocarbon that has both aliphatic and aromatic portions.</p> <footer class="mt-content-footer"> <style>/*<![CDATA[*/#mt-toc-container {display: none !important;}/*]]>*/</style><script type="text/javascript">/*<![CDATA[*/ $(function() { if(!window['autoDefinitionList']){ window['autoDefinitionList'] = true; $('dl').find('dt').on('click', function() { $(this).next().toggle('350'); }); } });/*]]>*/</script> <script defer="true" src="https://static.cloudflareinsights.com/beacon.min.js" data-cf-beacon="{"token": "483ec2414e274209a7e93c253192df0b"}"></script><script src="https://cdn.libretexts.net/github/LibreTextsMain/Miscellaneous/h5p-resizer.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/iframe-resizer/4.2.11/iframeResizer.contentWindow.min.js" integrity="sha512-FOf4suFgz7OrWmBiyyWW48u/+6GaaAFSDHagh2EBu/GH/1+OQSYc0NFGeGeZK0gZ3vuU1ovmzVzD6bxmT4vayg==" crossorigin="anonymous"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/iframe-resizer/4.2.11/iframeResizer.min.js" integrity="sha512-HY1lApSG7xxx8mYzs/lxRs+c5AaDThRaa3pvQB6puiswvf2lWqMJVf+8qSGiL4ZXfHQoPIqbd1TlpqfycPo3cQ==" crossorigin="anonymous"></script><script>/*<![CDATA[*/window.addEventListener('load', function(){$('iframe').iFrameResize({warningTimeout:0, scrolling: 'omit'});})/*]]>*/</script><script>/*<![CDATA[*/ window.PageNum = "auto"; window.InitialOffset = "false"; window.PageName = "2.2: Hydrocarbons"; /*]]>*/</script> <script type="text/javascript">/*<![CDATA[*/ // var front = window.PageNum.trim(); if(front=="auto"){ front = window.PageName.replace('\"', '\\\"').trim(); //front = "'..string.matchreplace(PageName,'\"','\\\"')..'".trim(); if(front.includes(":")){ front = front.split(":")[0].trim(); if(front.includes(".")){ front = front.split("."); front = front.map((int)=>int.includes("0")?parseInt(int,10):int).join("."); } front+="."; } else { front = ""; } } front = front.trim(); function loadMathJaxScript() { try { const script = document.createElement('script'); script.id = "mathjax-script"; script.src = "https://cdn.jsdelivr.net/npm/mathjax@4/tex-mml-svg.js"; script.type = "text/javascript"; script.defer = true; document.head.appendChild(script); } catch (err) { console.error(err); } } document.addEventListener('DOMContentLoaded', (e) => { loadMathJaxScript(); }); if (window.PageName !== 'Realtime MathJax'){ MathJax = { options: { ignoreHtmlClass: "tex2jax_ignore", processHtmlClass: "tex2jax_process", menuOptions: { settings: { zscale: "150%", zoom: "Double-Click", assistiveMml: true, // true to enable assitive MathML collapsible: false, // true to enable collapsible math }, }, }, output: { scale: 0.85, mtextInheritFont: false, displayOverflow: "linebreak", linebreaks: { width: "100%", }, }, startup: { pageReady: () => { if (window.activateBeeLine) { window.activateBeeLine(); } return MathJax.startup.defaultPageReady(); }, }, chtml: { matchFontHeight: true, }, tex: { tags: "all", tagformat: { number: (n) => { if (window.InitialOffset) { const offset = Number(window.InitialOffset); if(!offset) { return front + n; // If offset is falsy (nan, undefined, etc.) } const added = Number(n) + offset; return front + added; } else { return front + n; } }, }, macros: { eatSpaces: ['#1', 2, ['', ' ', '\\endSpaces']], PageIndex: ['{' + front.replace(/\./g, '{.}') + '\\eatSpaces#1 \\endSpaces}', 1], test: ["{" + front + "#1}", 1], mhchemrightleftharpoons: "{\\unicode{x21CC}\\,}", xrightleftharpoons: ['\\mhchemxrightleftharpoons[#1]{#2}', 2, ''] }, packages: { "[+]": [ "mhchem", "color", "cancel", "ams", "tagformat" ], }, }, loader: { '[tex]/mhchem': { ready() { const {MapHandler} = MathJax._.input.tex.MapHandler; const mhchem = MapHandler.getMap('mhchem-chars'); mhchem.lookup('mhchemrightarrow')._char = '\uE42D'; mhchem.lookup('mhchemleftarrow')._char = '\uE42C'; } }, load: [ "[tex]/mhchem", "[tex]/color", "[tex]/cancel", "[tex]/tagformat", ], }, }; }; ///*]]>*/</script> <hr class="autoattribution-divider" /><div class="autoattribution"><p>This page titled <a target="_blank" class="internal mt-self-link" href="/Sandboxes/johnnyphung/biology/02:_The_Molecules_of_Life/2.02:_Hydrocarbons">2.2: Hydrocarbons</a> is shared under a <a rel="nofollow" href="https://creativecommons.org/licenses/by/3.0" target="_blank">CC BY 3.0</a> license and was authored, remixed, and/or curated by <a rel="nofollow" target="_blank" href="http://www.biology-pages.info/">John W. Kimball</a> via <a rel="nofollow" href="https://www.biology-pages.info/" target="_blank">source content</a> that was edited to the style and standards of the LibreTexts platform.</p></div> <script type="text/javascript">/*<![CDATA[*/ try { const pageTagsHolder = document.getElementById('pageTagsHolder'); if (pageTagsHolder) { const pageTagsRaw = pageTagsHolder.innerText; if (pageTagsRaw.includes('transcluded:yes')) { const attrSections = document.querySelectorAll('.autoattribution'); const attrDividers = document.querySelectorAll('.autoattribution-divider'); if (attrSections.length > 1 && attrDividers.length > 1) { /* Hide first AutoAttribution from transcluded page */ attrSections[0].style.display = 'none'; attrDividers[0].style.display = 'none'; } } } } catch (e) { console.error('[AutoAttribution Transclusion Removal] Error encountered!'); console.error(e); }/*]]>*/</script> <div id="librelens-attribution-list"></div></footer>
💾 Save to sandbox
Reset