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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 3.1 – 3.7

2 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Americans consume an average of 140 pounds of sugar per person per year Cellulose, found in plant cell walls, is the most abundant organic compound on Earth

3 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings A typical cell in your body has about 2 meters of DNA A typical cow produces over 200 pounds of methane gas each year

4 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Milk is among the healthier foods you can eat BIOLOGY AND SOCIETY: GOT LACTOSE? –It is rich in many nutrients But milk-containing foods make some people ill –This is called lactose intolerance

5 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings People who are lactose intolerant do not produce enough of the enzyme lactase –Their cells cannot break down and absorb lactose Lactose intolerance can be managed by –Eating lactose-free foods –Ingesting lactase in pill form Figure 3.1

6 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings A cell is mostly water ORGANIC MOLECULES –The rest of the cell consists mostly of carbon-based molecules –Organic chemistry is the study of carbon compounds

7 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Carbon is a versatile atom Carbon Chemistry –It has four electrons in an outer shell that holds eight –Carbon can share its electrons with other atoms to form up to four covalent bonds

8 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Carbon can use its bonds to –Attach to other carbons –Form an endless diversity of carbon skeletons Figure 3.2 Carbon skeletons vary in length Carbon skeletons may be unbranched or branched Carbon skeletons may have double bonds, which can vary in location Carbon skeletons may be arranged in rings

9 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The simplest organic compounds are hydrocarbons –These are organic molecules containing only carbon and hydrogen atoms –The simplest hydrocarbon is methane Figure 3.3 Structural formula Ball-and-stick model Space-filling model

10 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Larger hydrocarbons –Are the main molecules in the gasoline we burn in our cars The hydrocarbons of fat molecules provide energy for our bodies Figure 3.4

11 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Each type of organic molecule has a unique three- dimensional shape that defines its function in an organism –The molecules of your body recognize one another based on their shapes Receptor molecule Transmitting cell Receiving cell Signal molecule Figure 3.5

12 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings The unique properties of an organic compound depend not only on its carbon skeleton but also on the atoms attached to the skeleton –These atoms are called functional groups

13 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Some common functional groups Figure 3.6 Hydroxyl groupCarbonyl groupAmino groupCarboxyl group Found in alcohols and sugars Found in sugars Found in amino acids and urea in urine (from protein breakdown) Found in amino acids, fatty acids, and some vitamins

14 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings On a molecular scale, many of lifes molecules are gigantic Giant Molecules from Smaller Building Blocks –Biologists call them macromolecules –Examples: proteins, DNA

15 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Most macromolecules are polymers –Polymers are made by stringing together many smaller molecules called monomers –Cells link monomers by a process called dehydration synthesis Figure 3.7A Short polymerMonomer Longer polymer (a) Dehydration synthesis of a polymer

16 Copyright © 2004 Pearson Education, Inc. publishing as Benjamin Cummings Organisms also have to break down macromolecules –Cells do this by a process called hydrolysis Figure 3.7B (b) Hydrolysis of a polymer


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