Complex carbohydrates are known as polysaccharides

Complex carbohydrates are known as polysaccharides -...

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Complex carbohydrates are known as polysaccharides. Polysaccharides are formed by linking eight  or more monosaccharide molecules. Among the most important polysaccharides are starches, which  are composed of hundreds or thousands of glucose units linked to one another. Starches serve as a  storage form for carbohydrates. Microorganisms break down starch to use the glucose it contains for  their energy needs.  Another important polysaccharide is glycogen, which is related to starch. Many bacteria have  glycogen in thier cytoplasm. Still another is cellulose. Cellulose is also composed of glucose units,  but the units cannot be released from one another except by a few species of microorganisms,  especially those in the stomach of the cow and other ruminants. The cell walls of algae contain  cellulose, and certain fungi have this polysaccharide. Another polysaccharide called chitin is a 
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Unformatted text preview: primary constituent in the fungal cell wall. Lipids. Lipids are organic molecules composed of carbon, hydrogen, and oxygen atoms. In contrast to carbohydrates, the ratio of hydrogen atoms to oxygen atoms is much higher. Lipids include steroids, waxes, and the most familiar lipids, fats. Fat molecules are composed of a glycerol molecule and one, two, or three molecules of fatty acids. A fatty acid is a long chain of carbon atoms with associated hydroxyl (–OH) groups. At one end of the fatty acid is an organic acid (–COOH) group. The fatty acids in a fat may be all alike or all different. They are bound to the glycerol molecule during dehydration synthesis, a process that involves the removal of water (Figure 1 ). The number of carbon atoms in a fatty acid may be as few as four or as many as 24....
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This note was uploaded on 11/11/2011 for the course BIO 101 taught by Professor Pesthy during the Fall '07 term at Texas State.

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