{"id":109,"date":"2019-06-17T18:02:26","date_gmt":"2019-06-17T22:02:26","guid":{"rendered":"https:\/\/pressbooks.bccampus.ca\/053humanbiology\/chapter\/3-3-biochemical-compounds\/"},"modified":"2025-08-27T16:00:30","modified_gmt":"2025-08-27T20:00:30","slug":"3-5-biochemical-compounds","status":"publish","type":"chapter","link":"https:\/\/pressbooks.bccampus.ca\/053humanbiology\/chapter\/3-5-biochemical-compounds\/","title":{"raw":"3.5\u00a0Biochemical Compounds","rendered":"3.5\u00a0Biochemical Compounds"},"content":{"raw":"Created by:\u00a0CK-12\/Adapted by Christine Miller\r\n\r\n[h5p id=\"218\"]\r\n\r\nFigure 3.5.1 Carbo-licious!<\/em>\r\n

Carbs Galore<\/span><\/h1>\r\nWhat do all of these foods have in common? All of them consist mainly of large compounds called\u00a0[pb_glossary id=\"1293\"]carbohydrates[\/pb_glossary]<\/strong>, often referred to as \"carbs.\" Contrary to popular belief, carbohydrates are an important part of a healthy diet. They are also one of four major classes of biological [pb_glossary id=\"1354\"]macromolecules[\/pb_glossary]<\/strong>.\r\n
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Chemical Compounds in Living Things<\/h1>\r\n<\/div>\r\n\r\n[caption id=\"attachment_107\" align=\"alignright\" width=\"225\"]\"Image Figure 3.5.2 The individual beads represent monomers, and when the beads are connected to form the bracelet, it represents a polymer.<\/em>[\/caption]\r\n\r\nThe compounds found in living things are known as\u00a0biochemical compounds or biological molecules. Biochemical compounds\u00a0make up the\u00a0[pb_glossary id=\"1298\"]cells<\/strong>[\/pb_glossary]\u00a0and other structures of organisms. They also carry out life processes. Carbon is the basis of all\u00a0biochemical compounds, so carbon is essential to life on Earth. Without carbon, life as we know it could not exist.\r\n\r\nCarbon is so basic to life because of its\u00a0ability to form stable bonds with many elements, including itself. This property allows carbon to\u00a0create\u00a0a huge variety of very large and complex molecules. In fact, there are nearly 10 million carbon-based compounds in living things!\r\n\r\nMost biochemical compounds are very large molecules called polymers. A\u00a0[pb_glossary id=\"1368\"]polymer[\/pb_glossary]<\/strong>\u00a0is built of repeating units of smaller compounds called\u00a0[pb_glossary id=\"1356\"]monomers[\/pb_glossary].<\/strong>\u00a0Monomers are like the individual beads on a string of beads, and the whole string is the polymer. The individual beads (monomers) can do some jobs on their own, but sometimes you need a larger molecule, so the monomers can be connected to form polymers.\r\n\r\n \r\n
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Classes of Biochemical Compounds<\/h1>\r\n<\/div>\r\nAlthough there are millions of different biochemical compounds in Earth's living things, all biochemical compounds contain the elements carbon, hydrogen, and oxygen. Some contain only these elements, while others contain additional elements, as well. The vast number of biochemical compounds can be grouped into just four major classes:\u00a0[pb_glossary id=\"1293\"]carbohydrates<\/strong>[\/pb_glossary],\u00a0[pb_glossary id=\"1292\"]lipids<\/strong>[\/pb_glossary],\u00a0[pb_glossary id=\"1373\"]proteins<\/strong>[\/pb_glossary], and\u00a0[pb_glossary id=\"1203\"]nucleic acids<\/strong>[\/pb_glossary].\r\n

Carbohydrates<\/h2>\r\n[caption id=\"attachment_107\" align=\"alignright\" width=\"197\"]\"Image Figure 3.5.3 Glucose is a common monosaccharide which can form large polymers including starch, glycogen and cellulose.<\/em>[\/caption]\r\n\r\n[pb_glossary id=\"1293\"]Carbohydrates<\/strong>[\/pb_glossary] include sugars and starches. These compounds contain only the elements carbon, hydrogen, and oxygen.\u00a0In living things, carbohydrates\u00a0provide\u00a0[pb_glossary id=\"1342\"]energy<\/strong>[\/pb_glossary]\u00a0to\u00a0cells,\u00a0store\u00a0energy, and\u00a0form\u00a0certain structures (such as the cell walls of plants). The [pb_glossary id=\"1356\"]monomer<\/strong>[\/pb_glossary] that makes up large carbohydrate compounds is called a monosaccharide. The sugar glucose, represented by the chemical model in Figure 3.5.2, is a monosaccharide. It contains six carbon atoms (C), along with several atoms of hydrogen (H) and oxygen (O). Thousands of glucose molecules can join together to form a polysaccharide, such as starch.\r\n\r\n \r\n

Lipids<\/span><\/h2>\r\n[caption id=\"attachment_107\" align=\"alignleft\" width=\"300\"]\"Image Figure 3.5.4 Fats and oils are examples of lipids<\/em>[\/caption]\r\n\r\n[pb_glossary id=\"1292\"]Lipids<\/strong>[\/pb_glossary] include fats and oils. They primarily contain the elements carbon, hydrogen, and oxygen, although some lipids contain additional elements, such as phosphorus. Lipids function in living things to store [pb_glossary id=\"1342\"]energy<\/strong>[\/pb_glossary],\u00a0form\u00a0cell membranes, and\u00a0carry\u00a0messages. Lipids consist of repeating units that join together to form chains called fatty acids.\u00a0Most naturally occurring fatty acids have an unbranched chain of an even number (generally\u00a0between\u00a04 and 28) of carbon atoms.\r\n

Proteins<\/h2>\r\n[caption id=\"attachment_107\" align=\"alignright\" width=\"300\"]\"Image Figure 3.5.5 There are many sources of dietary protein.<\/em>[\/caption]\r\n\r\n[pb_glossary id=\"1373\"]Proteins<\/strong>[\/pb_glossary]\u00a0include\u00a0[pb_glossary id=\"1345\"]enzymes<\/strong>[\/pb_glossary], antibodies, and many other important compounds in living things. They contain the elements carbon, hydrogen, oxygen, nitrogen, and sulfur. Functions of proteins are very numerous. They help [pb_glossary id=\"1298\"]cells[\/pb_glossary]<\/strong>\u00a0keep their shape,\u00a0compose\u00a0muscles,\u00a0speed\u00a0up\u00a0[pb_glossary id=\"1330\"]chemical reactions<\/strong>[\/pb_glossary], and\u00a0carry\u00a0messages and materials. The monomers that make up large\u00a0protein\u00a0compounds are called\u00a0[pb_glossary id=\"1319\"]amino acids<\/strong>[\/pb_glossary].\u00a0There are 20 different\u00a0amino acids\u00a0that combine into long chains (called polypeptides) to form the building blocks of a vast array of proteins in living things.\r\n

Nucleic Acids<\/h2>\r\n[pb_glossary id=\"1203\"]Nucleic acids<\/strong>[\/pb_glossary]\u00a0include the molecules\u00a0[pb_glossary id=\"1735\"]DNA<\/strong>[\/pb_glossary] (deoxyribonucleic acid) and [pb_glossary id=\"2228\"]RNA<\/strong>[\/pb_glossary](ribonucleic acid). They contain the elements carbon, hydrogen, oxygen, nitrogen, and phosphorus. Their functions in living things are to encode instructions for making proteins, to help make proteins, and to pass instructions between parents and offspring. The monomer that makes up nucleic acids is the nucleotide. \u00a0All nucleotides are the same, except for a component called a nitrogen base. There are four different nitrogen bases, and each nucleotide contains one of these four bases. The sequence of nitrogen bases in the chains of nucleotides in DNA and RNA makes up the code for protein synthesis, which is called the genetic code. The animation in Figure 3.3.5 represents the very complex structure of DNA, which consists of two chains of nucleotides.\r\n\r\n[caption id=\"attachment_107\" align=\"aligncenter\" width=\"182\"]\"A Figure 3.5.6 DNA is a polymer made of many monomers called nucleotides. DNA carries all the instructions a cell needs to carry out metabolism.<\/em>[\/caption]\r\n\r\n
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3.5 Summary<\/span><\/h1>\r\n<\/header>\r\n
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