Lesson 02.08 DBA/Module Exam
Lesson 02.01: Chemistry of Life
Explain why biological macromolecules are important for everyday life. Cells make large macromolecules by bonding smaller molecules together into chains called polymers (from the Greek polys, "many," and meris, "part"). Polymers are large molecules composed of many identical or similar subunits called monomers. There are four categories of biological macromolecules that provide energy and structure to living organisms and their cells. The four types of macromolecules are: ·
Compare the structure and function of carbohydrates, lipids, proteins, and nucleic acids. lipids Fat molecules are made up of carbon, hydrogen, and oxygen atoms. These macromolecules are made up of smaller molecules, one glycerol and three fatty acids, which is why fats are also called triglycerides. This is an example of a fat molecule. Notice that the three fatty acids are each bonded to the glycerol. The fatty acid molecules may vary in the number of atoms, usually 16 to 18 carbons, and they may have single or double bonds between the carbon atoms. Fats are stored in the body in fat deposits, which serve as stored energy for the organism. Fat deposits under the skin can also provide insulation for an animal, while fat surrounding vital organs provides protection and cushion for the organs. Although fats, carbohydrates, and proteins all serve as energy sources, digesting fat macromolecules releases much more energy than an equal amount of the others. One gram of fat can provide about 38 kilojoules of energy, compared to around 17 kilojoules of energy from one gram of carbohydrate or protein.Steroids are another category of lipids. The macromolecules in this category all share a similar structure of four linked rings of carbon atoms. proteins They are used for structure, transporting other substances, storage, signaling from one part of an organism to another, movement, and defense against foreign substances. Proteins are large biological macromolecules that are made up of smaller molecules called amino acids carbohydrates A monosaccharide—the prefix mono means “one”—is the smallest type of carbohydrate molecule. There are many types of monosaccharide molecules, the two most common being glucose and fructose. Monosaccharides, particularly glucose, are important energy sources for cells. In addition to providing energy, the carbon atoms in glucose can be used by the cells to build other important molecules, like fatty acids and amino acids. If the monosaccharides are not used by the cells immediately, they can be stored in larger carbohydrate molecules to be used later. disaccharides are carbohydrate molecules made up of two monosaccharide molecules bonded together. Monosaccharides and disaccharides are classified as simple carbohydrates. Most simple carbohydrates have a sweet taste, and they are collectively referred to as "sugars" in biology. Table sugar, called sucrose, is a disaccharide that you probably use every day. It is made up of one fructose molecule and one glucose molecule bonded together. Lactose, the major sugar in milk, is made of one glucose molecule and one galactose molecule bonded together. Maltose is a disaccharide produced during the digestion of starch. It is made of two glucose molecules. Polysaccharides are carbohydrate polymers made up of hundreds to thousands of monosaccharide units bonded together. The polysaccharides that are produced and consumed by living organisms, such as starch, cellulose, and glycogen, are all made up of the monomer glucose. Even though they are all made up of the same monomer, their properties are different because of the differences in how the glucose molecules are arranged in the different polysaccharides. Nucleic acids are large biological molecules[->0] essential for all known forms of life[->1]. They include DNA[->2] (deoxyribonucleic acid) and RNA[->3] (ribonucleic acid)....
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