copyright © 2007 pearson education inc., publishing as pearson benjamin cummings lectures by chris...
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Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Lectures by Chris C. Romero
PowerPoint® Lectures forEssential Biology, Third Edition – Neil Campbell, Jane Reece, and Eric SimonEssential 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.
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• Larger hydrocarbons
– Are the main molecules in the gasoline we burn in our cars.
• The hydrocarbons of fat molecules provide energy for our bodies.
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• The functional groups of an organic compound participate in chemical reactions
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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
monomer
monomer
monomer
monomer