Carbon and. Molecular Diversity. Organic Molecules. The Carbon Atom. Carbon s Compatibility. Variations in Carbon Skeletons 10/13/2015

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1 Organic Molecules Carbon and Molecular Diversity What is an organic molecule? Molecule that contains carbon What are the major elements of life? C, H, N, O, P, and S The Carbon Atom What makes the carbon atom so important to life? The electron configuration of carbon makes it tetravalent. The carbon atom has 4 valence electrons! Carbon s Compatibility What atoms does Carbon frequently bond with? H, O, N (& other C atoms) Learn the valence/bonding capacity for all 4 of these atoms! This explains how carbon makes large complex molecules possible. Variations in Carbon Skeletons TETRAVALENCE makes large complex molecules with a variety of shapes possible How can variations in carbon skeletons effect the structure and function of organic molecules? Change the length of the carbon skeleton. Alter the number and location of double bonds. Change the elements with which carbon bonds. 1

2 Hydrocarbons What is a hydrocarbon chain? It is a long C-H chain What type of bond is the C-H bond? Non-polar covalent Examples of hydrocarbons: fossil fuel component framework for large organic macromolecules of life Carbon compounds Skeleton may have single or double bonds Isomers What is an isomer? Molecules that have the same molecular formula but different structures. Isomers geometric isomers structural isomers sterioisomers or entantiomers vary in spatial arrangement vary in covalent arrangement vary in spatial arrangement around asymetric carbon STRUCTURAL isomers differing covalent bonding arrangement GEOMETRIC isomers - differ in arrangement around a DOUBLE BOND C 6 H 12 O 6 C 6 H 12 O 6 C 6 H 12 O trans- form cis- form 2

3 Be Careful! Single bonds can rotate! ENANTIOMER isomers - differ in arrangement around a ASYMMETRIC carbon... it s still the same stuff AP Biology by Campbell and Reese; Benjamin Cummings Mirror images Functional Groups Are regions of organic molecules Have specific chemical and physical properties Behave consistently from one organic molecule to another Effect the structure and function of organic molecules to which they belong. 3

4 A. Hydroxyl Group What does it look like? C-OH What are some characteristics? Alcohols Polar and water soluble Names end in -ol (ethanol) B. Carbonyl Group What does it look like? C=O At the end of a molecule - called aldehyde Ex. Glucose Within a molecule - called ketone Ex. Fructose What are some characteristics? Polar and water soluble Found in all sugars C. Carboxyl Group How did it get its name? COOH - This group consists of a carbon atom that is bonded to both a carbonyl and a hydroxyl group. Why is this group acidic? It donates H + Compounds with this group are called carboxylic acids D. Amino Group Either C-NH 2 or C-NH 3 Called amines What causes this group to be considered a weak base? The C-NH 2 tends to gain H +, removing them from the solution. 4

5 Functional Groups Amino Group Can act as a base and pick up a H + ion Carboxyl Group can act as an acid and give up a H + ion H R -C -COO- +NH 3 E. Sulfhydryl Group C-SH What is a function of this group? Helps stabilize protein structure through disulfide bridges. Called thiols F. The Phosphate Group PO 4 2- What are some characteristics of this group? Acidic, loses H +. Polar, water soluble Unstable.. important for energy (ATP) transfer and storage. G. The METHYL Group CH 3 What are some characteristics of this group? Addition of this group to DNA or to molecules bound to DNA, affects expression of genes Arrangement of this group in male and female sex hormones affects their shape and function 5