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2. LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Carbon and the Molecular Diversity of Life Chapter 4

3. Figure 4.9-a STRUCTURE CHEMICAL GROUP Hydroxyl NAME OF COMPOUND EXAMPLE Ethanol Alcohols (Their specific names usually end in -ol.) (may be written HO—) Carbonyl Ketones if the carbonyl group is within a carbon skeleton Aldehydes if the carbonyl group is at the end of the carbon skeleton Carboxyl Acetic acid Acetone Propanal Carboxylic acids, or organic acids FUNCTIONAL PROPERTIES Is polar as a result of the electrons spending more time near the electronegative oxygen atom. Can form hydrogen bonds with water molecules, helping dissolve organic compounds such as sugars. A ketone and an aldehyde may be structural isomers with different properties, as is the case for acetone and propanal. Ketone and aldehyde groups are also found in sugars, giving rise to two major groups of sugars: ketoses (containing ketone groups) and aldoses (containing aldehyde groups). Found in cells in the ionized form with a charge of 1  and called a carboxylate ion. Nonionized Ionized Acts as an acid; can donate an H + because the covalent bond between oxygen and hydrogen is so polar:

4. Figure 4.9-b AminoSulfhydrylPhosphateMethyl Methylated compounds Organic phosphates (may be written HS—) Thiols Amines Glycine Cysteine Acts as a base; can pick up an H + from the surrounding solution (water, in living organisms): NonionizedIonized Found in cells in the ionized form with a charge of 1+. Two sulfhydryl groups can react, forming a covalent bond. This “cross-linking” helps stabilize protein structure. Cross-linking of cysteines in hair proteins maintains the curliness or straightness of hair. Straight hair can be “permanently” curled by shaping it around curlers and then breaking and re-forming the cross-linking bonds. Contributes negative charge to the molecule of which it is a part (2– when at the end of a molecule, as above; 1– when located internally in a chain of phosphates). Molecules containing phosphate groups have the potential to react with water, releasing energy. Arrangement of methyl groups in male and female sex hormones affects their shape and function. Addition of a methyl group to DNA, or to molecules bound to DNA, affects the expression of genes. Glycerol phosphate 5-Methyl cytidine

5. Overview: Carbon: The Backbone of Life Living organisms consist mostly of carbon-based compounds Carbon likes to make four bonds. That lets it make big, complex molecules Proteins, DNA, carbohydrates, and other molecules that distinguish living matter are all composed of carbon compounds © 2011 Pearson Education, Inc.

6. Concept 4.1: Organic chemistry is the study of carbon compounds Organic chemistry is the study of compounds that contain carbon Organic compounds range from simple molecules to colossal ones Most organic compounds contain hydrogen atoms in addition to carbon atoms © 2011 Pearson Education, Inc.

7. Concept 4.2: Carbon atoms can form diverse molecules by bonding to four other atoms Valence electrons determine characteristics (atoms want full, empty or eight electrons) Carbon has four valence electrons (needs 4) Too many to take, too many to give up will share © 2011 Pearson Education, Inc.

8. Electron configuration determines the kinds and number of bonds an atom will form with other atoms ionic covalent  No reaction

9. An ion’s charge is determined by the number of electrons that it gains or looses Four valence electrons

10. The Formation of Bonds with Carbon four valence electrons = four covalent bonds Why carbon can make big, complex molecules © 2011 Pearson Education, Inc. Carbon with four single bonds: tetrahedral double bonds between carbons create a flat molecule

11. Figure 4.3 Name and Comment Molecular Formula (a) Methane (b) Ethane CH 4 Ball-and- Stick Model Space-Filling Model (c) Ethene (ethylene) C2H6C2H6 C2H4C2H4 Structural Formula

12. Four valence electrons in carbon: why it can make covalent bonds with so many things © 2011 Pearson Education, Inc. Most common carbon bonds: hydrogen, oxygen, nitrogen basis of living molecules

13. Carbon atoms can partner with atoms other than hydrogen; for example: –Carbon dioxide: CO 2 –Urea: CO(NH 2 ) 2 © 2011 Pearson Education, Inc.

14. Molecular Diversity = Carbon chain Variation Carbon chains found in most organic molecules Have different length and shape © 2011 Pearson Education, Inc. Animation: Carbon Skeletons

15. Hydrocarbons Hydrocarbons = hydrogen and carbon Many organic molecules, such as fats, have hydrocarbon components Hydrocarbons can react to release a large amount of energy © 2011 Pearson Education, Inc.

16. Figure 4.6 Nucleus Fat droplets (b) A fat molecule(a) Part of a human adipose cell 10  m

17. Isomers: molecular shape & function Isomers = compounds with the same molecular formula but different structures and properties –Structural isomers have different covalent arrangements of their atoms: chain branching © 2011 Pearson Education, Inc. Animation: Isomers

18. Isomers: molecular shape & function –Cis-trans isomers have the same covalent bonds but differ in spatial arrangements –Enantiomers are isomers that are mirror images of each other © 2011 Pearson Education, Inc. Animation: Isomers

19. Enantiomers are important in the pharmaceutical industry Two enantiomers of a drug may have different effects Usually only one isomer is biologically active © 2011 Pearson Education, Inc. Animation: L-Dopa

20. Figure 4.8 Drug Ibuprofen Albuterol Condition Effective Enantiomer Ineffective Enantiomer Pain; inflammation Asthma S-IbuprofenR-Ibuprofen R-Albuterol S-Albuterol

21. ATP: An Important Source of Energy for Cellular Processes One phosphate molecule, adenosine triphosphate (ATP), is the primary energy- transferring molecule in the cell ATP consists of an organic molecule called adenosine attached to a string of three phosphate groups © 2011 Pearson Education, Inc.

22. Figure 4. UN04 Adenosine

23. The Chemical Elements of Life: A Review The versatility of carbon makes possible the great diversity of organic molecules Variation at the molecular level lies at the foundation of all biological diversity © 2011 Pearson Education, Inc.

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