{"id":4364,"date":"2019-06-17T18:05:56","date_gmt":"2019-06-17T18:05:56","guid":{"rendered":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/chapter\/3-6-proteins-3\/"},"modified":"2023-11-30T17:50:15","modified_gmt":"2023-11-30T17:50:15","slug":"3-6-proteins-3","status":"publish","type":"chapter","link":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/chapter\/3-6-proteins-3\/","title":{"raw":"3.6 Proteins","rendered":"3.6 Proteins"},"content":{"raw":"<h1 style=\"margin-top: 2.14286em; margin-bottom: 1.42857em; line-height: 1.28571em;\"><span style=\"font-size: 1.424em;\">Protein\u00a0Shake<\/span><\/h1>\r\n[caption id=\"attachment_387\" align=\"alignright\" width=\"232\"]<img class=\" wp-image-387\" src=\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2019\/06\/Protein_shake-2.jpg\" alt=\"Image shows a glass containing a brown protein shake. Beside the glass are the ingredients used to make the shake: a small container of protein powder and a larger container of milk.\" width=\"232\" height=\"239\" \/> <em>Figure 3.6.1 Protein shakes vary in quality based on which amino acids they contain.<\/em>[\/caption]\r\n\r\nDrinks like this shake contain a lot of\u00a0protein. Muscle tissue consists mainly of protein, so such drinks are popular with people who want to build muscle. Making up\u00a0muscles\u00a0is just one of a plethora of functions of this amazingly diverse class of biochemicals.\r\n<div>\r\n<h1>What Are Proteins?<\/h1>\r\n<\/div>\r\n<strong>[pb_glossary id=\"5813\"]Proteins[\/pb_glossary]<\/strong>\u00a0are a major class of\u00a0biochemical compounds\u00a0made up of small monomer molecules called\u00a0<strong>[pb_glossary id=\"5707\"]amino acids[\/pb_glossary]<\/strong><strong>.\u00a0<\/strong>More than\u00a020 different\u00a0amino acids\u00a0are\u00a0typically\u00a0found in the proteins of living things. Small proteins may contain just a few hundred amino acids,\u00a0while\u00a0large proteins may contain thousands.\r\n<div>\r\n<h1>Protein Structure<\/h1>\r\n<\/div>\r\nWhen amino acids bind together, they may form short chains of two or just a few amino acids. These short chains are called\u00a0<strong>peptides<\/strong>. When amino acids form long chains, the chains are called\u00a0<strong>polypeptides<\/strong>. A protein consists of one or more polypeptides.\r\n\r\nProteins may have up to four levels of structure, from primary to quaternary.\u00a0\u00a0<span style=\"font-size: 1em;\">As a result, they can have\u00a0tremendous diversity. Here are some additional details about the levels of protein structure:<\/span>\r\n<p style=\"text-align: center;\"><img class=\"wp-image-389 aligncenter\" src=\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Structures-of-Protein-2.jpg\" alt=\"\" width=\"545\" height=\"726\" \/><\/p>\r\n<p style=\"text-align: center;\"><em>Figure 3.6.2 Four protein structures.<\/em><\/p>\r\n\r\n<div>\r\n<h1><span style=\"font-size: 1.424em;\">Functions of Proteins<\/span><\/h1>\r\n<\/div>\r\nThe diversity of protein structures explains\u00a0why\u00a0this class of\u00a0biochemical compounds\u00a0can play so many important roles in living things. What are the roles of proteins?\r\n<ul>\r\n \t<li>Some proteins have structural functions. They may help [pb_glossary id=\"5665\"]cells[\/pb_glossary] keep their shape or make up muscle tissues.<\/li>\r\n \t<li>Many proteins are\u00a0[pb_glossary id=\"5757\"]enzymes[\/pb_glossary]\u00a0that\u00a0speed\u00a0up\u00a0[pb_glossary id=\"5729\"]chemical reactions[\/pb_glossary]\u00a0in\u00a0cells.\u00a0Enzymes\u00a0are usually highly specific and accelerate only one or a few\u00a0chemical reactions. Thousands of different\u00a0biochemical reactionsare known to be catalyzed by enzymes, including most of the reactions involved in metabolism. A reaction without an\u00a0enzyme\u00a0might take millions of years to complete, whereas with the proper enzyme, it may take just a few milliseconds!<\/li>\r\n \t<li>Other proteins are\u00a0<strong>[pb_glossary id=\"5659\"]antibodies[\/pb_glossary]<\/strong>, which\u00a0bind to specific foreign substances,\u00a0like\u00a0proteins on the surface of bacterial\u00a0cells. This process targets the cells for destruction.<\/li>\r\n \t<li>Still other proteins carry messages or materials. Myoglobin, for example, is\u00a0an oxygen-binding protein found in the muscle tissues of most mammals (including humans).<\/li>\r\n<\/ul>\r\n<span style=\"text-align: initial; font-size: 1em;\">The chief characteristic of proteins that allows their diverse set of functions is their ability to bind to other molecules so specifically and tightly. Myoglobin can bind specifically and tightly with oxygen. The region of a protein responsible for binding with another molecule is known as the\u00a0<\/span><strong style=\"text-align: initial; font-size: 1em;\">binding site.<\/strong><span style=\"text-align: initial; font-size: 1em;\">\u00a0This site is often a depression on the molecular surface, determined largely by the tertiary structure of the protein.<\/span>\r\n<div>\r\n<h1>Protein Consumption, Digestion, and Synthesis<\/h1>\r\n<\/div>\r\n[pb_glossary id=\"5813\"]Proteins[\/pb_glossary] are necessary in the diets of humans and other\u00a0animals. We cannot make all the different [pb_glossary id=\"5707\"]amino acids[\/pb_glossary] we need, so we must obtain some of them from the foods we consume.\u00a0In\u00a0the process of digestion, we break down the proteins in food into free amino acids that can then be used to synthesize our own proteins.\u00a0Protein synthesis\u00a0from amino\u00a0acid monomers takes place in all cells and is controlled by genes. Once new proteins are synthesized, they generally do not last very long before they are degraded and their amino acids are recycled. A protein's lifespan in mammalian cells is generally just a day or two.\r\n<div>\r\n<div class=\"textbox textbox--key-takeaways\"><header class=\"textbox__header\">\r\n<h1 class=\"textbox__title\"><span style=\"color: #ffffff;\">3.6 Summary<\/span><\/h1>\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n<ul>\r\n \t<li>[pb_glossary id=\"5813\"]Proteins[\/pb_glossary] are a major class of\u00a0biochemical compounds. They're made up of small [pb_glossary id=\"5781\"]monomer[\/pb_glossary] molecules called [pb_glossary id=\"5707\"]amino acids[\/pb_glossary]. More than 20 amino acids are commonly found in the proteins of living things. Proteins have tremendous diversity in terms of both structure and function.<\/li>\r\n \t<li>Long chains of amino acids form polypeptides. The sequence of amino acids in polypeptides makes up the primary structure of proteins. Proteins also have higher levels of structure. Secondary structure refers to configurations \u2014 such as helices and sheets \u2014 within polypeptide chains. Tertiary structure is a protein's overall three-dimensional shape, which controls the molecule's basic function. A quaternary structure forms if multiple protein molecules join together and function as a complex.<\/li>\r\n \t<li>Proteins\u00a0help cells keep their shape, make up muscle tissues, act as\u00a0enzymes\u00a0or antibodies, and carry messages or materials. The chief characteristic that allows proteins' diverse functions is their ability to bind specifically and tightly with other molecules.<\/li>\r\n \t<li>We cannot make all the amino acids we need to synthesize our own proteins, so we must obtain some of them from proteins in the foods we consume.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox textbox--exercises\"><header class=\"textbox__header\">\r\n<h1 class=\"textbox__title\"><span style=\"color: #ffffff;\">3.6 Review Questions<\/span><\/h1>\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n<ol>\r\n \t<li>What are proteins?<\/li>\r\n \t<li>Outline the four levels of protein structure.<\/li>\r\n \t<li>Identify four functions of proteins.<\/li>\r\n \t<li>Explain why proteins can take on so many different functions in living things.<\/li>\r\n \t<li>What is the role of proteins in the human diet?<\/li>\r\n \t<li>Can you have a protein with both an alpha helix and a pleated sheet? Why or why not?<\/li>\r\n \t<li>If there is a mutation in a gene that causes a different amino\u00a0acid\u00a0to be encoded than the one usually encoded in that position within the protein, would that affect:\r\n<ul>\r\n \t<li>The primary structure of the protein? Explain your answer.<\/li>\r\n \t<li>The higher structures (secondary, tertiary, quaternary) of the protein? Explain your answer.<\/li>\r\n \t<li>The function of the protein? Explain your answer.<\/li>\r\n<\/ul>\r\n<\/li>\r\n \t<li>What is the region of a protein responsible for binding to another molecule? Which level or levels of protein structure creates this region?<\/li>\r\n \t<li>What is the region of a protein responsible for binding to another molecule? Which level or levels of protein structure creates this region?<\/li>\r\n \t<li>[h5p id=\"458\"]<\/li>\r\n \t<li><em>True or False: <\/em>You can tell the function of all proteins\u00a0based on\u00a0their quaternary structure.<\/li>\r\n \t<li>Explain what the reading means when it says that amino acids are \u201crecycled.\u201d<\/li>\r\n<\/ol>\r\n<\/div>\r\n<\/div>\r\n<div class=\"textbox textbox--examples\"><header class=\"textbox__header\">\r\n<h1 class=\"textbox__title\">3.6 Explore More<\/h1>\r\n<\/header>\r\n<div class=\"textbox__content\">\r\n\r\nhttps:\/\/youtu.be\/hok2hyED9go\r\n<p style=\"text-align: center;\">Protein Structure and Folding by The Amoeba Sisters, 2018.<\/p>\r\n\r\n<\/div>\r\n<\/div>\r\n<h2>Attributions<\/h2>\r\n<strong>Figure 3.6.1<\/strong>\r\n\r\n<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Protein_shake.jpg\" rel=\"cc:attributionURL\">Protein_shake<\/a> by <a title=\"User:Sandstein\" href=\"https:\/\/commons.wikimedia.org\/wiki\/User:Sandstein\">Sandstein<\/a>, on Wikimedia Commons, is used under a <a href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/deed.en\">CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.\r\n\r\n<strong>Figure 3.6.2<\/strong>\r\n\r\n<\/div>\r\n<a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Figure_03_04_09.jpg\" rel=\"cc:attributionURL\">Structures of Protein<\/a> by <a href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.53\">OpenStax<\/a>, on Wikimedia Commons, is used under a <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\">CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/4.0) license.\r\n<h2>References<\/h2>\r\n<p class=\"hanging-indent\"><span class=\"list-comma\">Amoeba Sisters. (2018, September 24). Protein structure and folding. YouTube. https:\/\/www.youtube.com\/watch?v=hok2hyED9go<\/span><\/p>\r\n<p class=\"hanging-indent\"><span class=\"list-comma\">OpenStax<\/span><span class=\"list-comma\">. (2012, Aug 22). Figure 9. The four levels of protein structure can be observed in these illustrations. (credit: modification of work by National Human Genome Research Institute)<\/span>. In <em>Biology<\/em>. OpenStax CNX. \u00a9 Rice University. https:\/\/cnx.org\/contents\/GFy_h8cu@10.53:2zzm1QG9@7\/Proteins (last revised May 27, 2016).<\/p>\r\n<p style=\"text-align: left;\"><\/p>","rendered":"<h1 style=\"margin-top: 2.14286em; margin-bottom: 1.42857em; line-height: 1.28571em;\"><span style=\"font-size: 1.424em;\">Protein\u00a0Shake<\/span><\/h1>\n<figure id=\"attachment_387\" aria-describedby=\"caption-attachment-387\" style=\"width: 232px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-387\" src=\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2019\/06\/Protein_shake-2.jpg\" alt=\"Image shows a glass containing a brown protein shake. Beside the glass are the ingredients used to make the shake: a small container of protein powder and a larger container of milk.\" width=\"232\" height=\"239\" \/><figcaption id=\"caption-attachment-387\" class=\"wp-caption-text\"><em>Figure 3.6.1 Protein shakes vary in quality based on which amino acids they contain.<\/em><\/figcaption><\/figure>\n<p>Drinks like this shake contain a lot of\u00a0protein. Muscle tissue consists mainly of protein, so such drinks are popular with people who want to build muscle. Making up\u00a0muscles\u00a0is just one of a plethora of functions of this amazingly diverse class of biochemicals.<\/p>\n<div>\n<h1>What Are Proteins?<\/h1>\n<\/div>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5813\">Proteins<\/a><\/strong>\u00a0are a major class of\u00a0biochemical compounds\u00a0made up of small monomer molecules called\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5707\">amino acids<\/a><\/strong><strong>.\u00a0<\/strong>More than\u00a020 different\u00a0amino acids\u00a0are\u00a0typically\u00a0found in the proteins of living things. Small proteins may contain just a few hundred amino acids,\u00a0while\u00a0large proteins may contain thousands.<\/p>\n<div>\n<h1>Protein Structure<\/h1>\n<\/div>\n<p>When amino acids bind together, they may form short chains of two or just a few amino acids. These short chains are called\u00a0<strong>peptides<\/strong>. When amino acids form long chains, the chains are called\u00a0<strong>polypeptides<\/strong>. A protein consists of one or more polypeptides.<\/p>\n<p>Proteins may have up to four levels of structure, from primary to quaternary.\u00a0\u00a0<span style=\"font-size: 1em;\">As a result, they can have\u00a0tremendous diversity. Here are some additional details about the levels of protein structure:<\/span><\/p>\n<p style=\"text-align: center;\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-389 aligncenter\" src=\"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-content\/uploads\/sites\/152\/2023\/10\/Structures-of-Protein-2.jpg\" alt=\"\" width=\"545\" height=\"726\" \/><\/p>\n<p style=\"text-align: center;\"><em>Figure 3.6.2 Four protein structures.<\/em><\/p>\n<div>\n<h1><span style=\"font-size: 1.424em;\">Functions of Proteins<\/span><\/h1>\n<\/div>\n<p>The diversity of protein structures explains\u00a0why\u00a0this class of\u00a0biochemical compounds\u00a0can play so many important roles in living things. What are the roles of proteins?<\/p>\n<ul>\n<li>Some proteins have structural functions. They may help <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5665\">cells<\/a> keep their shape or make up muscle tissues.<\/li>\n<li>Many proteins are\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5757\">enzymes<\/a>\u00a0that\u00a0speed\u00a0up\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5729\">chemical reactions<\/a>\u00a0in\u00a0cells.\u00a0Enzymes\u00a0are usually highly specific and accelerate only one or a few\u00a0chemical reactions. Thousands of different\u00a0biochemical reactionsare known to be catalyzed by enzymes, including most of the reactions involved in metabolism. A reaction without an\u00a0enzyme\u00a0might take millions of years to complete, whereas with the proper enzyme, it may take just a few milliseconds!<\/li>\n<li>Other proteins are\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5659\">antibodies<\/a><\/strong>, which\u00a0bind to specific foreign substances,\u00a0like\u00a0proteins on the surface of bacterial\u00a0cells. This process targets the cells for destruction.<\/li>\n<li>Still other proteins carry messages or materials. Myoglobin, for example, is\u00a0an oxygen-binding protein found in the muscle tissues of most mammals (including humans).<\/li>\n<\/ul>\n<p><span style=\"text-align: initial; font-size: 1em;\">The chief characteristic of proteins that allows their diverse set of functions is their ability to bind to other molecules so specifically and tightly. Myoglobin can bind specifically and tightly with oxygen. The region of a protein responsible for binding with another molecule is known as the\u00a0<\/span><strong style=\"text-align: initial; font-size: 1em;\">binding site.<\/strong><span style=\"text-align: initial; font-size: 1em;\">\u00a0This site is often a depression on the molecular surface, determined largely by the tertiary structure of the protein.<\/span><\/p>\n<div>\n<h1>Protein Consumption, Digestion, and Synthesis<\/h1>\n<\/div>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5813\">Proteins<\/a> are necessary in the diets of humans and other\u00a0animals. We cannot make all the different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5707\">amino acids<\/a> we need, so we must obtain some of them from the foods we consume.\u00a0In\u00a0the process of digestion, we break down the proteins in food into free amino acids that can then be used to synthesize our own proteins.\u00a0Protein synthesis\u00a0from amino\u00a0acid monomers takes place in all cells and is controlled by genes. Once new proteins are synthesized, they generally do not last very long before they are degraded and their amino acids are recycled. A protein&#8217;s lifespan in mammalian cells is generally just a day or two.<\/p>\n<div>\n<div class=\"textbox textbox--key-takeaways\">\n<header class=\"textbox__header\">\n<h1 class=\"textbox__title\"><span style=\"color: #ffffff;\">3.6 Summary<\/span><\/h1>\n<\/header>\n<div class=\"textbox__content\">\n<ul>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5813\">Proteins<\/a> are a major class of\u00a0biochemical compounds. They&#8217;re made up of small <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5781\">monomer<\/a> molecules called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_4364_5707\">amino acids<\/a>. More than 20 amino acids are commonly found in the proteins of living things. Proteins have tremendous diversity in terms of both structure and function.<\/li>\n<li>Long chains of amino acids form polypeptides. The sequence of amino acids in polypeptides makes up the primary structure of proteins. Proteins also have higher levels of structure. Secondary structure refers to configurations \u2014 such as helices and sheets \u2014 within polypeptide chains. Tertiary structure is a protein&#8217;s overall three-dimensional shape, which controls the molecule&#8217;s basic function. A quaternary structure forms if multiple protein molecules join together and function as a complex.<\/li>\n<li>Proteins\u00a0help cells keep their shape, make up muscle tissues, act as\u00a0enzymes\u00a0or antibodies, and carry messages or materials. The chief characteristic that allows proteins&#8217; diverse functions is their ability to bind specifically and tightly with other molecules.<\/li>\n<li>We cannot make all the amino acids we need to synthesize our own proteins, so we must obtain some of them from proteins in the foods we consume.<\/li>\n<\/ul>\n<\/div>\n<\/div>\n<div class=\"textbox textbox--exercises\">\n<header class=\"textbox__header\">\n<h1 class=\"textbox__title\"><span style=\"color: #ffffff;\">3.6 Review Questions<\/span><\/h1>\n<\/header>\n<div class=\"textbox__content\">\n<ol>\n<li>What are proteins?<\/li>\n<li>Outline the four levels of protein structure.<\/li>\n<li>Identify four functions of proteins.<\/li>\n<li>Explain why proteins can take on so many different functions in living things.<\/li>\n<li>What is the role of proteins in the human diet?<\/li>\n<li>Can you have a protein with both an alpha helix and a pleated sheet? Why or why not?<\/li>\n<li>If there is a mutation in a gene that causes a different amino\u00a0acid\u00a0to be encoded than the one usually encoded in that position within the protein, would that affect:\n<ul>\n<li>The primary structure of the protein? Explain your answer.<\/li>\n<li>The higher structures (secondary, tertiary, quaternary) of the protein? Explain your answer.<\/li>\n<li>The function of the protein? Explain your answer.<\/li>\n<\/ul>\n<\/li>\n<li>What is the region of a protein responsible for binding to another molecule? Which level or levels of protein structure creates this region?<\/li>\n<li>What is the region of a protein responsible for binding to another molecule? Which level or levels of protein structure creates this region?<\/li>\n<li>\n<div id=\"h5p-458\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-458\" class=\"h5p-iframe\" data-content-id=\"458\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Size of Proteins\"><\/iframe><\/div>\n<\/div>\n<\/li>\n<li><em>True or False: <\/em>You can tell the function of all proteins\u00a0based on\u00a0their quaternary structure.<\/li>\n<li>Explain what the reading means when it says that amino acids are \u201crecycled.\u201d<\/li>\n<\/ol>\n<\/div>\n<\/div>\n<div class=\"textbox textbox--examples\">\n<header class=\"textbox__header\">\n<h1 class=\"textbox__title\">3.6 Explore More<\/h1>\n<\/header>\n<div class=\"textbox__content\">\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Protein Structure and Folding\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/hok2hyED9go?feature=oembed&#38;rel=0&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p style=\"text-align: center;\">Protein Structure and Folding by The Amoeba Sisters, 2018.<\/p>\n<\/div>\n<\/div>\n<h2>Attributions<\/h2>\n<p><strong>Figure 3.6.1<\/strong><\/p>\n<p><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Protein_shake.jpg\" rel=\"cc:attributionURL\">Protein_shake<\/a> by <a title=\"User:Sandstein\" href=\"https:\/\/commons.wikimedia.org\/wiki\/User:Sandstein\">Sandstein<\/a>, on Wikimedia Commons, is used under a <a href=\"https:\/\/creativecommons.org\/licenses\/by\/3.0\/deed.en\">CC BY 3.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/3.0) license.<\/p>\n<p><strong>Figure 3.6.2<\/strong><\/p>\n<\/div>\n<p><a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Figure_03_04_09.jpg\" rel=\"cc:attributionURL\">Structures of Protein<\/a> by <a href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.53\">OpenStax<\/a>, on Wikimedia Commons, is used under a <a href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\">CC BY 4.0<\/a> (https:\/\/creativecommons.org\/licenses\/by\/4.0) license.<\/p>\n<h2>References<\/h2>\n<p class=\"hanging-indent\"><span class=\"list-comma\">Amoeba Sisters. (2018, September 24). Protein structure and folding. YouTube. https:\/\/www.youtube.com\/watch?v=hok2hyED9go<\/span><\/p>\n<p class=\"hanging-indent\"><span class=\"list-comma\">OpenStax<\/span><span class=\"list-comma\">. (2012, Aug 22). Figure 9. The four levels of protein structure can be observed in these illustrations. (credit: modification of work by National Human Genome Research Institute)<\/span>. In <em>Biology<\/em>. OpenStax CNX. \u00a9 Rice University. https:\/\/cnx.org\/contents\/GFy_h8cu@10.53:2zzm1QG9@7\/Proteins (last revised May 27, 2016).<\/p>\n<p style=\"text-align: left;\">\n<div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">definition<\/span><template id=\"term_4364_5813\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5813\"><div tabindex=\"-1\"><p>A class of biological molecule consisting of linked monomers of amino acids and which are the most versatile macromolecules in living systems and serve crucial functions in essentially all biological processes.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5707\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5707\"><div tabindex=\"-1\"><p>Amino acids are organic compounds that combine to form proteins.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5665\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5665\"><div tabindex=\"-1\"><p>The smallest unit of life, consisting of at least a membrane, cytoplasm, and genetic material.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5757\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5757\"><div tabindex=\"-1\"><p>Biological molecules that lower amount the energy required for a reaction to occur.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5729\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5729\"><div tabindex=\"-1\"><p>A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5659\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5659\"><div tabindex=\"-1\"><p>An antibody, also known as an immunoglobulin, is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to neutralize pathogens such as pathogenic bacteria and viruses.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><template id=\"term_4364_5781\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_4364_5781\"><div tabindex=\"-1\"><p>A molecule that can undergo polymerization, creating macromolecules.  Large numbers of monomers combine to form polymers in a process called polymerization.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Close definition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":32,"menu_order":6,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":"cc-by-nc"},"chapter-type":[48],"contributor":[],"license":[55],"class_list":["post-4364","chapter","type-chapter","status-publish","hentry","chapter-type-numberless","license-cc-by-nc"],"part":4320,"_links":{"self":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapters\/4364","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/wp\/v2\/users\/32"}],"version-history":[{"count":4,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapters\/4364\/revisions"}],"predecessor-version":[{"id":6370,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapters\/4364\/revisions\/6370"}],"part":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/parts\/4320"}],"metadata":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapters\/4364\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/wp\/v2\/media?parent=4364"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/pressbooks\/v2\/chapter-type?post=4364"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/wp\/v2\/contributor?post=4364"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/pressbooks.ccconline.org\/acchumanbio\/wp-json\/wp\/v2\/license?post=4364"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}