Lecture 3 Inorganic compounds o minerals inorganic elements passed up food chain by plants 4 body weight 75 Ca P contribute to body structure bones and teeth oxygen and carbon dioxide are most important oxygen many reactants release energy from food carbon dioxide byproduct of respiration must be expelled to maintain acid base homeostasis gases o o acids electrolytes salts that ionize in water to form body fluids capable of conducting electricity importance chemical reactivity osmotic effects influence water movement electrical effects on nerve and muscle tissue imbalances cause muscle cramps brittle bones coma and death release H is an acid acid proton donor o hydrogen loses its 1 electron becomes hydrogen ion positive charge due to single proton anions atoms that gained an electron neg charge cations atoms that lost an electron pos charge o bases or alkalis electrolytes that release negatively charge OH or hydroxyl ions contains hydroxide groups proton acceptors take up hydrogen ions forms water OH H H2O taste bitter feel slippery o pH Potential of Hydrogen measures the concentration of H ions in solution less than 7 is acidic solution greater than 7 is basic solution 7 0 is neutral pH must balance acids and bases for homeostasis pH scale measures relative acidity alkalinity logarithmic scale 0 14 change of one number 10 fold change in H concentration pH 4 10x more H ions than pH 5 pH 4 100x more H ions than pH6 o salts electrolyte that dissociates into cations and anions neither of which is an H or OH pH 7 NaCl Na Cl many salts in cells and fluids source of essential elements sodium calcium potassium Acid reacts with base product is water and a salt o buffers chemical that resists large sudden change in pH convert strong acids to weak base strong base to weak acid increase pH buffer realease H acts as an acid decrease pH buffer binds to H acts as a base keeps body fluids within homeostatic pH range o free radicals particle with odd number of electrons ex oxygen molecule with extra electron produced by normal metabolic reactions radiation chemicals causes tissue damage reactions that destroy molecules causes cancer death of heart tissue and aging antioxidants neutralize free radicals in diet vitamin E carotenoids vitamin C organic substances o o o o contain carbon except carbon monoxide carbon dioxide generally large complex molecules formed by smaller molecules by covalent bonding with carbon carbon electrically neutral never loses or gains electrons shares them needs 4 valence electrons allows wide variety of elements to form complex molevules hydrogen oxygen nitrogen phosphorus sulfur backbone for organic molcules o main structural components of body materials o energy source for most life processes participate in thousands of metabolic reactions serve as enzymes that regulate reactions structural formula of isomers molecular formulae are identical but structural formulas differ for grain alcohol and ether carbohydrate molecules CHO o o o o hydrophilic organic molecule general formula CH2O n n number of carbon atoms for glucose n 6 so formula is C6H12O6 2 1 ratio of hydrogen to oxygen Names of carbohydrates word root sacchar or the suffix ose often used monosaccharide or glucose surface of plasma membrane form glyococalyx functions all digested carbs converted to glucose and oxidized to make ATP conjugated carbohydrate bound to lipid or protein o glycolipids external surface of cell membrane o glycoproteins external surface of cell membrane mucus of respiratory and digestive tracts o proteoglycans gels that hold cells and tissues together joint lubricaion rubbery texture of cartilage classified by size complexity and water solubility monosaccharides o simple sugars o 3 7 carbons o most soluble disaccharides building blocks for more complex CHO o double sugars o 6 14 carbonds o more complex less soluble o pairs of monosaccharides o must be digested to simple sugars to be absorbed o sucrose maltose lactose o 3 or more monosaccharides o many carbons o most complex least soluble o glycogen and cellulose gives fiber to our diet polysaccharides molecules and chemical bonds plants compounds two or more atoms of different elements covalently bonded o molecules two or more atoms covalently bonded o o molecular formula C6H12O6 elements and how many atoms of each o lipids o structural formula location of each atom and structural isomers revealed hydrophobic organic molecule composed of carbon hydrogen and oxygen less oxidized and thus has more calories per gram five primary types in humans fatty acids triglycerides phospholipids eicosanoids steroids o o o most concentrated source of energy o important component of cell membrane in many hormones classified by solubility triglycerides neutral fats o o o 3 fatty acids bonded to glycerol molecule dehydration synthesis at room temperature liquid oils often polyunsaturated fats from plants solid fats saturated fats from animals function energy storage insulation and shock absorption composed of glycerol and 3 fatty acid chains glycerol is the same for all fats many different fatty acids fatty acids o chain of 4 to 24 carbon atoms carboxyl acid group on one end mathyl group on the other and hydrogen bonded along the sides mostly hydrogen attached classified differ by number and arrangement of carbon and hydrogen saturated carbon atoms saturated with hydrogen maximum number of hydrogen solid at room butter lard animal fats associated with heart disease artherosclerosis unsaturate contains double bonded carbon atoms C C that could form with an additional hydrogen 1 double carbon bond monounsaturated 2 or more double carbon bonds polyunsaturated phospholipids o triglyceride with one fatty acid replaced by a phosphate group amphilphillic character fatty acid tails are hydrophobic phosphate head is hydrophilic phosphorus group gives phospholipids distinct chemical properties phosphorus base head is water soluble hydrophilic attracted to water fatty acid tail is water insoluble hydrophobic repelled by water in water phospholipids orient into lipid bilayer double layer of phospholipids base or head faces water fatty acid tail faces inward away from water o lipid classification o steroids structure different from other fats or phospholipids carbon atoms in 4 interlocking rings cholesterol is most abundant steroid 85 from body 15 from diet others include testosterone estrogen progesterone bile salts lipoid substances fat soluble vitamins A D E K