Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Lectures by Chris C. Romero PowerPoint ® Lectures for Essential Biology, Third Edition – Neil Campbell, Jane Reece, and Eric Simon Essential Biology with Physiology, Second Edition – Neil Campbell, Jane Reece, and Eric Simon The Chemistry of Carbon

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Organic Molecules A cell is mostly water. The rest of the cell consists mostly of carbon-based molecules –organic compounds. –Over 2 million organic compounds known. –Life’s diversity results from the variety of organic compounds in cells. –Organic chemistry is the study of carbon compounds.

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Carbon Chemistry Carbon is a versatile atom. –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. Carbon can use its bonds to –Attach to other carbons. –Form an endless diversity of carbon skeletons.

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings The simplest organic compounds are hydrocarbons. –These are organic molecules containing only carbon and hydrogen atoms. –Composed of a carbon skeleton with hydrogens attached to the carbons.

Copyright © 2007 Pearson Education Inc., publishing as Pearson 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.

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings The functional groups of an organic compound participate in chemical reactions

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Giant Molecules from Smaller Building Blocks On a molecular scale, many of life’s molecules are gigantic. –Biologists call them macromolecules. –Examples: DNA, carbohydrates Most macromolecules are polymers. –Polymers are made by stringing together many smaller molecules called monomers. –A huge number of different polymers can be made from a small number of monomers.

Figure 3.6a Cells link monomers to form polymers by dehydration synthesis

Figure 3.6b Polymers are broken down to monomers by the reverse process, hydrolysis

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings dehydration synthesis or hydrolysis. 1.Connects monomers to form a polymer. 2.Produces water as a by- product. 3.Breaks up polymers, forming monomers. 4.Water is used to break bonds between monomers. 5.Joins amino acids to form a protein. 6.Glycerol and fatty acids combine to form a fat. 7.Occurs when polysaccharides are digested to form monosaccharides. 8.-H and –OH groups form water. 9.Nucleic acid breaks up to form nucleotides. 10.Water breaks up.

Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings Includes 4 important types of Biological molecules monomer