Chapter 4: Carbon and the Molecular Diversity of Life

1. Chapter 4: Carbon and the Molecular Diversity of Life

2. Essential Knowledge 1.d.1 – There are several hypotheses about the natural origin of life on Earth, each with supporting scientific evidence (4.1). 2.a.3 – Organisms must exchange matter with the environment to grow, reproduce, and maintain organization (4.1 & 4.2).

3. OrganicChemistry The study of carbon compounds. Usually involves the study of living things

4. Major Elements Of Organic Molecules Carbon: +4 or -4 Hydrogen: +1 Oxygen: -2 Nitrogen: -3

5. Hydrocarbons Organic molecules made of only carbon and hydrogen.

6. Carbon’s versatility Forms 4 covalent bonds (because it has 4 valence e-) Molecular shape is tetrahedral Bonds very easily to itself

7. Carbon, continued Can form nearly 10 million compounds 15 known isotopes: C-14 (age of fossils), C-13, C-12 Naturally occurring in hardest (diamonds) and one of softest (graphite) forms on Earth

8. Carbon, continued Very small size (capable of forming multiple bonds) Major economic use—petroleum, other fossil fuels Others: pencil “lead”, steel, charcoal, medicine

9. Organic Isomers Compounds with the same molecular formula but have different structures. Result: Different molecular and chemical properties.

10. Which of these are isomers? No Yes Yes No

11. 3 Types Of Isomers Structural Geometric (cis/trans) Enantiomers

12. 1. Structural Isomers Butane Isobutane Different in covalent arrangements of their atoms.

13. 2. Geometric Isomers Same covalent partnership but differ in spatial arrangements. Arise from the inflexibility of double bonds. Also known as cis/trans isomers

14. 3. Enantiomers Molecules that are mirror images of each other. Usually involve an asymmetric carbon.

15. Comment Organisms are sensitive to even the most subtle variations in molecular architecture. This is why isomers (and their shape/characteristics) are critical to biochemistry

16. Example - Thalidomide Cells can’t distinguish between two isomers. One is an effective drug. The other causes birth defects. Used (in 1970s) as a “cure” for morning sickness

17. Functional Groups A group of atoms attached to a carbon skeleton. Have consistent properties. Their number and kind give properties to the molecule.

18. Importance of Functional Groups

19. Figure 4.9 Memorize!!!

20. Hydroxyl Group A hydrogen atom bonded to an oxygen atom. Ex. -OH Very polar. Allows the material to be hydrophilic. Forms alcohols.

21. Carbonyl Group • A carbon atom joined to an oxygen atom by a double bond. Ex. - C=O • Polar tendencies • Two types of Carbonyl Group compounds: • Aldehydes • Ketones

22. Carbonyl: Aldehydes A carbonyl group at the end of a carbon skeleton. Ex. - C=O H Sometimes written as - CHO

23. Carbonyl: Ketones A carbonyl group in the middle of a carbon chain. Ex. -C-C-C- || O

24. Carboxyl Group • Group with a carbon double bonded to an oxygen and to a hydroxyl group. Ex. - C=O | OH • Written as: -COOH • Also called Carboxylic Acids • Donate H+ (acid). • Form many weak organic acids.

25. Amino Group • Nitrogen bonded to two hydrogens. Ex. – N-H | H • Forms compounds called amines. • Act as a base. • IF combined with carboxyl, can act as an acid! • Ex: amino acids

26. Sulfhydryl Group Sulfur bonded to a hydrogen. Ex. -SH Forms compounds called thiols. Help with protein structure. Acidic properties

27. Phosphate Group Phosphorus with four oxygens. Ex. -PO4 Has a net -2 charge. Sometimes written as “Pi”. Involved with energy transfers.

28. Methyl Group Carbon bonded to three hydrogens. - CH3 Very non-polar and hydrophobic. Ex: fossil fuels (any other hydrocarbon)

29. Summary Identify what is meant by organic chemistry. Recognize the valences for the major elements of organic molecules. Recognize various types of isomers. Identify the functional groups and their structure and properties.