Biochemistry Biochemistry: study of chemical composition and reactions of living matter Inorganic compounds Do not contain carbon Water, salts, and many acids and bases Organic compounds Contain carbon, are covalently bonded, and are often large Properties of Water High heat capacity absorbs and releases large amounts of heat before changing temperature redistributes heat, maintain homeostasis High heat of vaporization changing from a liquid to a gas requires large amounts of heat sweating removes heat Properties of Water Polar solvent properties dissolves ionic substances, forms hydration layers around large charged molecules, and serves as the bodys major transport medium Properties of Water Reactivity is an important part of hydrolysis and dehydration synthesis reactions Cushioning resilient cushion around certain body organs Salts Inorganic compounds Contain cations other than H + and anions other than OH Are electrolytes; they conduct electrical currents NaCl, CaCO 3, KCl Acids and Bases Acids release H + (proton donors) HCl H + + Cl Bases release OH (proton acceptors) NaOH Na + + OH Acid-Base Concentration (pH) based on concentration oh hydrogen ions in solution, expressed in moles per liter (molarity) logarithmic (each change of 1 pH unit is a tenfold change in H + ) Acid-Base Concentration (pH) Acidic solutions have higher H + concentration and therefore a lower pH (06.99) Alkaline solutions have lower H + concentration and therefore a higher pH (7.0114) Neutral solutions have equal H + and OH concentrations (pH 7.00) Organic Compounds Molecules unique to living systems contain carbon and hence are organic compounds They include: Carbohydrates Lipids Proteins Nucleic Acids Carbohydrates contain carbon, hydrogen, and oxygen 1-2% of cell mass Examples: Monosaccharides Disaccharides Polysaccharides Monosaccharides (simple sugars) contain carbon, hydrogen, and oxygen (CH 2 0) supply a source of cellular food named by number of C in ring (hexose, pentose) Examples: Disaccharides (double sugars) two monosaccharides joined via dehydration synthesis Polysaccharides (polymers of simple sugars) starch and glycogen storage (plant and animal) Lipids Contain C, H, and O, but the proportion of oxygen in lipids is less than in carbohydrates Examples: Neutral fats or triglycerides Phospholipids Steroids Eicosanoids Neutral Fats (Triglycerides) Composed of three fatty acids bonded to a glycerol molecule Other Lipids Phospholipids modified triglycerides with two fatty acid groups and a phosphorus group Other Lipids Steroids flat molecules with four interlocking hydrocarbon rings Representative Lipids Found in the Body Amino Acids Building blocks of protein, containing an amino group and a carboxyl group Amino group NH 2 Carboxyl groups COOH Amino Acids Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid Dehydration synthesis Hydrolysis Dipeptide Peptide bond +N H H C R H O N H H C R CC H O H2OH2O H2OH2O N H H C R C H O N H C R C H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid +N H H C R H O N H H C R CC H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid Dehydration synthesis +N H H C R H O N H H C R CC H O H2OH2O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid Dehydration synthesis Dipeptide Peptide bond +N H H C R H O N H H C R CC H O H2OH2O N H H C R C H O N H C R C H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Dipeptide Peptide bond N H H C R C H O N H C R C H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Hydrolysis Dipeptide Peptide bond H2OH2O N H H C R C H O N H C R C H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid Hydrolysis Dipeptide Peptide bond +N H H C R H O N H H C R CC H O H2OH2O N H H C R C H O N H C R C H O OH Protein Macromolecules composed of combinations of 20 types of amino acids bound together with peptide bonds Amino acid Dehydration synthesis Hydrolysis Dipeptide Peptide bond +N H H C R H O N H H C R CC H O H2OH2O H2OH2O N H H C R C H O N H C R C H O OH Structural Levels of Proteins Primary amino acid sequence Secondary alpha helices or beta pleated sheets Tertiary superimposed folding of secondary structures Quaternary polypeptide chains linked together in a specific manner Structural Levels of Proteins Fibrous Proteins Extended and strand-like proteins Globular Proteins Compact, spherical proteins with tertiary and quaternary structures Nucleic Acids Composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus Their structural unit, the nucleotide, is composed of N-containing base, a pentose sugar, and a phosphate group Nucleic Acids Five nitrogen bases contribute to nucleotide structure adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) Two major classes DNA and RNA Deoxyribonucleic Acid (DNA) Double-stranded helical molecule found in the nucleus of the cell Replicates itself before the cell divides, ensuring genetic continuity Provides instructions for protein synthesis Structure of DNA Ribonucleic Acid (RNA) Single-stranded molecule found in both the nucleus and the cytoplasm of a cell Uses the nitrogenous base uracil instead of thymine Three varieties of RNA: messenger RNA, transfer RNA, and ribosomal RNA Adenosine Triphosphate (ATP) Source of immediately usable energy for the cell Adenine-containing RNA nucleotide with three phosphate groups Adenosine Triphosphate (ATP)