Chapter 2: The Chemistry of Life Honors Coordinated Science II Ms. Wheatley-Heckman

Properties of Water Polar Hydrogen Bonds Cohesion Adhesion

Mixtures Water is often found as parts of a mixture Mixture = material composed of two of more elements that are physically mixed together but not chemically combined.

Solutions Mixture of 2 or more substances in which the molecules of the substances are evenly distributed. Solute = substance that is dissolved Solvent = substance in which the solute dissolves.

Suspensions Mixtures of water and non-dissolved materials. Example: Blood—mostly water with dissolved compounds, but also contains cells and other nondissolved compounds.

Acids, Bases, and pH H2O H+ + OH- A water molecule can react to form ions. H2O H+ + OH- Water Hydrogen Ion + Hydroxide Ion

Acids, Bases, and pH pH scale measures the concentration of H+ ions in a solution. Acidic solutions have higher concentrations of H+ ions than pure water and have pH values below 7. Basic (Alkaline) solutions contain lower H+ concentrations than pure water an have pH values above 7.

Carbon Compounds Carbon can form 4 strong covalent bonds. Has ability to form long chains, and even rings.

Macromolecules Giant molecules made from thousands of smaller molecules. Monomer = a small molecule which is a building block for larger molecules. Polymers = a long chain molecule that is made from many monomers bonded together. Polymerization = a chemical reaction that joins monomers together to produce a polymer.

ethylene polyethylene Many ethylene monomers can be combined to produce polyethylene, which is used to make many plastic products such as bags, bottles, containers, wraps, etc. polymerization ethylene polyethylene Many styrene monomers can be combined to make polystyrene, which is used to make disposable cutlery, CD & DVD cases, packing materials, insulation, foam drink cups, etc.

Dehydration Synthesis Joins together 2 monomers with the loss of a water molecule.

Hydrolysis Breaks apart a polymer by adding a water molecule at each bond.

Biochemistry There are 4 classes of biologically important molecules which we will discuss in this course: Carbohydrates Lipids Nucleic Acids Proteins

Carbohydrates Made of C, H, and O atoms (usually in a 1:2:1 ratio) Main source of energy for living things. Used for structure in plants and some animals.

Carbohydrates Monosaccharides = single unit sugars (i.e. glucose, fructose, galactose) Disaccharides = two sugars bonded together (i.e. sucrose, lactose) Polysaccharides = long chain of 10 or more sugars bonded together (i.e glycogen, cellulose)

Lipids Not soluble in water. Used to store energy. Important parts of biological membranes and waterproof coverings. Many are formed when a glycerol molecule combines with fatty acids.

Nucleic Acids Contain Hydrogen, Oxygen, Nitrogen, Carbon, and Phosphorus Assembled from monomers called nucleotides. Store and transmit hereditary or genetic information. Deoxyribonucleic acid (DNA) and Ribonucleic Acid (RNA)

Nucleotide Structure A nucleotide’s structure includes a 5 carbon sugar, a nitrogenous base, and a phosphate group. Nitrogenous Base 5 Carbon Sugar

Proteins Proteins are polymers of amino acids. The sequence of amino acids needed to make a protein is encoded in the cell’s genetic code. Proteins are essential to many cell processes and have a variety of functions, including: Serving as enzymes to catalyze reactions. Playing a structural role as part of the cytoskeleton that helps to maintain a cell’s shape. Transmitting or receiving signals in the cell. Playing roles in the immune system and cell division.

Chemical Reactions and Enzymes Chemical Reaction = process that changes one set of chemicals into another. Reactants enter the chemical reaction and products are compounds produced by the reaction. CO2 + H2O  H2CO3 H2CO3  CO2 + H2O

Energy in Reactions Energy is released or absorbed whenever chemical bonds form or are broken. Activation Energy = energy needed to get a reaction started. Paper won’t burst into flames unless you light it with a match, which provides the necessary activation energy for the reaction.

Energy of a Reaction Energy is released here, because the energy of the products is less than the energy of the reactants.

Enzymes Some chemical reactions necessary for life have activation energies that are too high to make them practical. These reactions are made possible by catalysts Substance that speeds up a reaction by lowering activation energy. Enzymes are proteins that act as biological catalysts.

Enzyme Action Form “Enzyme-Substrate Complexes” Substrate = reactants of an enzyme-catalyzed reaction. http://www.youtube.com/watch?v=V4OPO6JQLOE

Enzymes are Sensitive Have ideal pH and temperature levels. If too far out of their ideal range, they will literally fall apart, or “denature”.