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Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential.

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Presentation on theme: "Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential."— Presentation transcript:

1 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint ® Lecture Slides for Essential Biology, Second Edition & Essential Biology with Physiology Neil Campbell, Jane Reece, and Eric Simon Presentation prepared by Chris C. Romero CHAPTER 3 The Molecules of Life Figures 3.8 – 3.15

2 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings There are four categories of large molecules in cells BIOLOGICAL MOLECULES –Carbohydrates –Lipids –Proteins –Nucleic acids

3 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Carbohydrates include Carbohydrates –Small sugar molecules in soft drinks –Long starch molecules in pasta and potatoes

4 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Monosaccharides are simple sugars Monosaccharides Figure 3.8 –Glucose, found in sports drinks –Fructose, found in fruit Honey contains both glucose and fructose

5 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The monosaccharides glucose and fructose are isomers –Their atoms are arranged differently Figure 3.9 GlucoseFructose

6 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings In aqueous solutions, monosaccharides form rings Monosaccharides are the main fuel that cells use for cellular work Figure 3.10 (a) Linear and ring structures (b) Abbreviated ring structure

7 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings A disaccharide is a double sugar Disaccharides –It is constructed from two monosaccharides

8 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Disaccharides are joined by the process of dehydration synthesis Figure 3.11 Glucose Maltose

9 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The most common disaccharide is sucrose, common table sugar –It consists of a glucose linked to a fructose –Sucrose is extracted from sugar cane and the roots of sugar beets

10 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The United States is one of the worlds leading markets for sweeteners –The average American consumes about 64 kg of sugar per year Figure 3.12

11 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Complex carbohydrates are called polysaccharides Polysaccharides –They are long chains of sugar units –They are polymers of monosaccharides

12 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Polysaccharides Figure 3.13 (a) Starch Starch granules in potato tuber cells Glucose monomer (b) Glycogen Glycogen Granules In muscle tissue (c) Cellulose Cellulose molecules Cellulose fibril in a plant cell wall

13 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings One familiar example of a polysaccharide is starch –Plant cells store starch for energy –Potatoes and grains are major sources of starch in the human diet

14 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Animals store excess sugar in the form of a polysaccharide called glycogen Glycogen is similar in structure to starch

15 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Cellulose is the most abundant organic compound on Earth –It forms cable-like fibrils in the tough walls that enclose plants –It is a major component of wood –It is also known as dietary fiber

16 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Most animals cannot derive nutrition from fiber –How do grazing animals survive on a diet of cellulose? –They have bacteria in their digestive tracts that can break down cellulose Figure 3.14

17 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Simple sugars and double sugars dissolve readily in water –They are hydrophilic, or water-loving

18 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Lipids are hydrophobic Lipids –They do not mix with water –Examples: fats and steroids

19 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Dietary fat consists largely of the molecule triglyceride Fats –A combination of glycerol and three fatty acids Figure 3.15a Fatty acid Glycerol (a) Dehydration synthesis linking a fatty acid to glycerol

20 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Fats perform essential functions in the human body –Energy storage –Cushioning –Insulation

21 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Unsaturated fatty acids –Have less than the maximum number of hydrogens bonded to the carbons Saturated fatty acids –Have the maximum number of hydrogens bonded to the carbons

22 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Figure 3.15B (b) A fat molecule

23 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Most animal fats have a high proportion of saturated fatty acids –Example: butter Most plant oils tend to be low in saturated fatty acids –Example: corn oil


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