EXSC 223 Chapter 2 Chemistry Comes Alive Biochemistry the study of the chemical composition and reactions of living matter Organic compounds contain carbon Inorganic compounds do not contain carbon Water high heat capacity high heat of vaporization polar solvent properties universal solvent hydration layers reactivity cushioning Electrolytes substances that conduct an electrical current in solution Acids a substance that releases hydrogen ions H in detectable amounts Also defined as a proton donor Bases proton acceptors they take up hydrogen ions H in detectable amounts Bicarbonate ion HCO3 an important base in the body particularly abundant in blood Ammonia NH3 a common waste product of protein breakdown in the body also a base pH Acid Base Concentration the more hydrogen ions in a solution the more acidic the solution Neutralization when acids and bases are mixed they react with each other in displacement reactions to form water and a salt Buffers resist abrupt and large swings in the pH of body fluids by releasing hydrogen ions acting as acids when the pH begins to rise and by binding hydrogen ions acting as bases when the pH drops Strong acids acids that dissociate completely and irreversibly in water Weak acids acids that do not dissociate completely Strong bases bases that dissociate easily in water and quickly tie up H Weak base accepts relatively few protons Carbonic acid bicarbonate system chemical blood buffer Carbohydrate a group of molecules that includes sugars and starches represents 1 2 of cell mass Carbohydrates contain carbon hydrogen and oxygen Monosaccharide disaccharide polysaccharide o Monosaccharides Pentose hexose galactose fructose Joined by removal of OH from one monomer and removal of H from the other Monomers are released by the addition of water molecules adding OH to one monomer and H to another o Disaccharides Sucrose lactose maltose o Polysaccharides Starch glycogen Lipids insulate the body organs build cell membranes and provide stored energy o Lipids Triglycerides neutral fats Fatty acids glycerol 3 1 ratio Saturated unsaturated Trans fat omega 3 fatty acids Catalyst Substance that o Lowers activation energy o Increases rate of reaction o Without being consumed by reaction Reaction was already going to happen but catalyst speeds up that process Energy of reaction is often heat Catalyst decreases the amount of energy needed for the reaction to proceed Non catalyzed reaction vs enzyme catalyzed reaction Catalyst in not consumed in the reaction Enzymes Biological catalyst Catalysts are very specific only drive one reaction o Therefore bodies have thousands of different enzymes Can exist as two parts o Apoenzymes protein portion o Cofactor assist the reaction Usually derived by a vitamin or mineral o You don t wake enzymes to catalyze everything o If you regulate the shape you regulate the function Only active when we want them to be active We can regulate biological catalysts by regulating the shape of the protein o There are some environmental influences Rate of Chemical Reactions Catalyst increase rate without being chemically changed o Enzymes are biological catalysts Reaction rates are influenced by o Increase in temperature increases rate of reaction Optimal temperature for smooth muscle tissue is 39 degrees C o Decrease in particle size increases rate of reaction Increasing temperature increases frequency of vibration Smaller particles vibrate more quickly increases reaction rate o Increase in concentration of reactant increases rate of reaction o Decrease in pH decreases rate of reaction Generally enzymes do not like acidic environment Example of biological catalyst Substrates bind to active site on enzyme create enzyme substrate complex energy is absorbed and bond is formed water is released and bond is broken substrate separates from enzyme Energy the capacity to do work Chemical energy ATP GTP CTP Heat energy ATP is important in a variety of different ways o Tags molecule with a phosphate group phosphorylation Can also de phosphorylate changes shape o Breaking down ATP to get phosphate group gives heat o Stored energy in form of glycogen form of adipose form of amino acids Energy Forms Chemical energy ATP ADP AMP Electrical nerve impulses Mechanical muscle shortening Radiant vision light waves ATP Based on ribose sugar 5 carbon sugar Amount of ATP ADP AMP and P are key metabolic regulators What is an Acid A compound which donates an H ion to another compound base Acids are sort of specific kind of salts because they break down into H and o Acid proton donor an anion o Example HCL H CL o Strength of acid is based on how completely it dissociates o HCL is a strong acid that is produced in the stomach o Example H2CO3 H HCO3 o Relatively weak because only some of it breaks down o Carbonic acid is the way we transport CO2 in the bloodstream o pH 6 to pH 5 increases free h by a factor of ten pH Scale Inverted scale o Low pH lots of free H Log scale acidic solution o High H low pH o Acidic pH 0 6 99 Alkaline solution basic o Low H high pH o Basic pH 7 01 14 Average blood pH 7 4 slightly basic 7 neutral pH change interferes with cell function and may damage tissue pH is regulated by kidneys liver buffers slight change in pH can be fatal Buffers mixture of compounds that resist pH change convert strong completely dissociated acids or bases into weak slightly dissociated ones need to manipulate number of free H example carbonic acid does this automatically in the blood