BIOCHEMISTRY The chemistry of the carbon atom Versatility of the carbon atom Bonds readily to itself, forms chains, rings, single and double bonds Hydrocarbons Isomers Polymers

I. Carbohydrates Sugars and their polymers CHO in a 1:2:1 ratio An –OH group is attached to each C except one which is double bonded to Oxygen Most common: Triose 3C glyceraldehyde Pentose 5C ribose Hexose 6C glucose

A. Monosaccharides Simple sugars C6H12O6 – glucose, fructose, galactose Arrangement of individual atoms makes them different compounds Glucose – hexose – building block for more complex sugars Fructose – fruit sugar Galactose – milk sugar

B. Disaccharides 2 monosaccharides joined by a glycosidic linkage through dehydration synthesis Maltose = glucose + glucose (brewing beer) Lactose = glucose + galactose (milk) Sucrose = glucose + fructose (table sugar)

C. Polysaccharides Polymer of a few hundred or thousand monosaccharides 2 important functions: 1. Energy storage (starch and glycogen) 2. Structural support (cellulose and chitin) Starch = alpha linkage Cellulose = beta linkage

II. LIPIDS Waxy or oily organic compounds Nonpolar; CHO in no particular ratio Fats, phospholipids, steroids Functions: Energy storage Bio membranes Chemical messengers Insulation Cushion vital organs

A. Fats Glycerol and 3 fatty acids Simple fat = triglyceride Properties depend on the fatty acids that it is composed of Saturated vs. unsaturated fatty acids

B. Phospholipids Glycerol, fatty acids (2) and a phosphate group (negatively charged) AMPHIPATHIC

C. Steroids Lipids with 4 fused carbon rings with various functional groups attached Amphipaathic Cholesterol, hormones

III. PROTEINS Polymers of amino acids Amino acids are the monomers

III. PROTEINS cont’d Amino acids can form covalent bonds with each other 20 AA in nature – each has a different “R” group R groups can be Polar Nonpolar special

III. PROTEINS Formation Two amino acids form a peptide bond through dehydration synthesis Peptide bond formed between acid group of one amino acid and and amino group of another 40 – 1,000 AA in MOST cellular proteins

PROTEINS Structure Primary – linear sequence of amino acids Secondary – folding due to H bonds (weak forces) (alpha helix, beta pleated sheet) Tertiary – more folding of helix due to hydrophobic/hydrophilic interactions of R groups Quaternary – two or more chains held together by weak forces

PROTEINS Functions Membrane structure (integral and peripheral) Enzymes (biological catalysts) Motion (muscle contraction) Energy (last resort) Transport (hemoglobin) Hormones (cellular control) Regulation of gene function Protection (immune system)

III. PROTEINS cont’d Denaturing occurs when temperature or pH changes or through treatment with urea 3D structure is destroyed – no function Primary structure is still intact; peptide bonds are strong covalent bonds that cannot be broken by change in pH, temp, etc

IV. NUCLEIC ACIDS DNA and RNA, molecules which contain directions to make proteins; determine physical appearance, internal makeup, etc Building blocks = nucleotides Nucleotide = sugar (5C), phosphate and a nitrogenous base In DNA, deoxyribose, phosphate, and one of four N bases (adenine, thymine, cytosine, guanine)

IV. NUCLEIC ACIDS cont’d RNA = ribose, phosphate group, and one of 4 N bases (adenine, uracil, cytosine and guanine) DNA = double helix; RNA single stranded Over 100 million base pairs in one human DNA molecule Base pairing rules In DNA bases joined together by H bonds to make up rungs of ladder