3.2 Molecules of Life 1.Carbohydrates 2.Proteins 3.Lipids 4.Nucleic Acids

3.2 Molecules of Life 1. Carbohydrates Composed of: –Carbon, oxygen, and hydrogen in a ratio of about –1 carbon to 2 hydrogen to 1 oxygen Monomer- monosaccharide Our main source of energy Used as structural materials in organisms

3.2 Molecules of Life Carbohydrate# of MonosaccharidesExample Monosaccharide Glucose (blood), fructose (fruit), galactose (milk) Disaccharide Sucrose, lactose, maltose Polysaccharide Glycogen(liver + muscle), starch (plants), cellulose (cell walls), chitin (exoskeletons of arthropods)

3.2 Molecules of Life Proteins Composed of: –Carbon, hydrogen, oxygen, and nitrogen –NO RATIO Monomer- amino acid Make up 50% of your dry weight Functions including structural, defensive, and catalytic roles

3.2 Molecules of Life Examples: –Enzymes: amylase, catalase, maltase –Structural: collagen –Contractile: actin, myosin (found in muscles) –Transport: hemoglobin (transports oxygen in the blood) –Storage –Hormones: insulin

3.2 Molecules of Life Amino Acids –Proteins are made up of monomers called amino acids –The sequence of amino acids determines a protein’s shape and function SerineThreonine

3.2 Molecules of Life Dipeptides and Polypeptides –Two amino acids are joined by peptide bonds to form a dipeptide –A long chain of amino acids is called a polypeptide

3.2 Molecules of Life Amino acid diagram

3.2 Molecules of Life Enzymes –Speed up chemical reactions –Bind to specific substrates (aka reactants) –The binding of a substrate with an enzyme causes a change in the enzyme’s shape and reduces the activation energy of the reaction –Typically named for the substrate they work on + “-ase” –The enzyme sucrase works on sucrose –Factors that affect enzymes: heat or pH

3.2 Molecules of Life