BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell Jane B. Reece Lawrence G. Mitchell Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 3 The Molecules of Cells Modules 3.4 – 3.10

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The monomers, the polymers and the macromolecules……. For each of the four macromolecules we will fill in an organizer to study from. We will start with the simple sugars which, when linked together, form the carbohydrates.

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Monosaccharides are single-unit sugars These molecules typically have a formula that is a multiple of CH 2 O. Their formula is C 6 H 12 O 6. Each molecule contains hydroxyl groups and a carbonyl group as their functional group. The hydroxyl group renders most sugars hydrophillic or water loving. Monosaccharides are the fuels for cellular work 3.4 Monosaccharides are the simplest carbohydrates. They are the monomers. Figure 3.4A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings The monosaccharides glucose, galactose and fructose are isomers –They contain the same atoms but in different arrangements GlucoseFructose Figure 3.4B Galactose

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Many monosaccharides form rings, as shown here for glucose Abbreviated structure Figure 3.4C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Monosaccharides can join to form disaccharides, such as sucrose (table sugar) and maltose (brewing sugar) and lactose (milk sugar) 3.5 Cells link single sugars to form disaccharides through dehydration synthesis. Glucose Maltose Sucrose=fruc- tose + glucose lactose

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Various types of molecules, including non- sugars, taste sweet because they bind to “sweet” receptors on the tongue. The tighter they bind the receptors, the sweeter the taste. 3.6 Connection: How sweet is sweet? Table 3.6

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbohydrates are a class of molecules –They range from small sugars to large polysaccharides –Polysaccharides are long polymers of monomers linked by dehydration synthesis. CARBOHYDRATES

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Starch (plants) and glycogen (animals) are polysaccharides that store sugar for later use Cellulose (plants) is a polysaccharide in plant cell walls. It passes as “fiber” through our digestive tract for most animals can not hydrolyze it. How do termites and cows get nutrients from plants???? Hum…. Figure 3.7 Starch granules in potato tuber cells Glucose monomer STARCH GLYCOGEN CELLULOSE Glycogen granules in muscle tissue Cellulose fibrils in a plant cell wall Cellulose molecules

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Carbohydrate morphology Starch- coils of branched glucose, plants use it for energy. Cellulose-rods of chains of glucose most abundant organic compound. B-glycosidic bonds prevent mammals from breaking it down to obtain glucose. Glycogen-stored in liver more branched than starch. Hydrolyzed in liver and digestive tract.

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings These compounds are composed largely of carbon and hydrogen –They are not true polymers –They are grouped together because they do not mix with water. They are hydrophobic. –Fats, oils, phospholipids and waxes are composed of glycerol and fatty acids. 3.8 Lipids include fats, which are mostly energy- storage molecules Figure 3.8A

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Fats are triglycerides whose main function is energy storage in animals. Oils are analogous in plants. Triglycerides= 3 fatty acid chains and a glycerol. A triglyceride molecule consists of one glycerol molecule linked to three fatty acids Figure 3.8B Fatty acid

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Unsaturated fatty acid chains (common in plant oils) contain double bonds. –These unsaturated fats form kinks which prevent them from solidifying at room temperature as they can not pack tightly together. They are better for you than saturated fats. Saturated fatty acid chains (common in animal lard) lack double bonds. They are solid at room temperature. They should be limited in the diet as they can pack tightly together and clog arteries and veins. Figure 3.8C

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Phospholipids are a major component of cell membranes. They are composed of two fatty acid chains and a glycerol. Waxes form waterproof coatings. They are composed of one fatty acid chain and a glycerol. Waxes are found on plants and in your ears. Steroids are often hormones 3.9 Phospholipids, waxes, and steroids are lipids with a variety of functions Figure 3.9

Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Anabolic steroids are usually synthetic variants of testosterone Use of these substances can cause serious health problems 3.10 Connection: Anabolic steroids and related substances pose health risks Figure 3.10