Cell Biology

Carbohydrates, fats, and proteinsFoods containthe compoundsyou are made ofWhat is acarbohydrate?Sugars aresimple moleculesStarches arelarger moleculesThe compounds that your cells are made of and that they use tofunction come from the foods you eat. Foods containcarbohydrates, fats (also known as lipids), and proteins. Theamount of each varies with different foods. What arecarbohydrates, fats, and proteins?Carbohydrates are energy-rich compounds made from carbon,hydrogen, and oxygen. Cells use carbohydrates to get and storeenergy. Plants contain cellulose, a carbohydrate that gives thema rigid structure.Carbohydrates are classified as sugars and starches. Sugarsare smaller molecules. Glucose is a simple sugar made of 6 carbon,12 hydrogen, and 6 oxygen atoms. The sugar you use to sweetenfood is called sucrose. A sucrose molecule is made from two glucosemolecules.Starch molecules are very large. They consist of many sugarmolecules combined. Plant cells store energy as starch. Many foodsthat contain starch come from plants. These include rice, potatoes,corn, and wheat.Figure 4.8: A glucose moleculecarbohydrates - energy-richcompounds such as sugars andstarches made from carbon,hydrogen, and oxygen.(discussed on next page)lipids - energy-rich compoundssuch as fats, oils, and waxes madefrom carbon, hydrogen, andoxygen.proteins - complex moleculesmade from smaller moleculescalled amino acids.76UNIT 2 CELL BIOLOGY