Know the number of bonds that can be formed by hydrogen carbon oxygen nitrogen and phosphorus Exam 1 Material o H 1 o C 4 o O 2 o N 2 P 5 o Understand the differences between covalent polar and nonpolar ionic hydrogen bonds and Van der Waals interactions and know which bonds are strongest and which are weakest o Covalent pairing of atoms in a chemical bond where the atoms share an electron Nonpolar equal sharing of the electron Polar uneven sharing of the electron o Ionic electrical attraction between two atoms one that has gained an electron and one that has lost one o Hydrogen bonds electrical attraction between compounds held together by polar covalent bonds o Van der Waals Interactions weak attraction of uncharged atoms Strength covalent ionic hydrogen bonding Van der Waals o Know that O H and N H and C O covalent bonds are polar with the oxygen and nitrogen holding a partial negative charge and the hydrogen or carbon having a partial positive charge C C and C H covalent bonds are nonpolar Understand the concepts molecular weight mole molarity and be able to calculate how many grams of a substance should be dissolved in a given volume of water to make a solution of a certain molarity o Molecular weight sum of the atomic weights of atoms in a molecule o Mole amount of a compound equal to its molecular weight in grams o Molarity M measure of the moles of a solute dissolved in a liter of a solution Know and understand the terms hydrophobic and hydrophilic be able to predict whether a molecule is hydrophilic or hydrophobic based on its molecular structure Know what an acid and a base is and understand the concepts of pH and pH scale be able to convert pH values into hydrogen ion concentrations o Hydrophilic water loving substances dissolve readily in water Molecules that have polar covalent or ionic bonds tend to be hydrophilic o Hydrophobic substances that do not dissolve in water Molecules that are nonpolar covalent bonds tend to be hydrophobic o Acid any substance that will dissolve in water yielding H and an anion or any substance that o Base a substance that dissolves and produces a hydroxyl ion or any substance that can accept can donate protons protons Strong acids and bases completely dissociate in water Weak acids and bases do not completely dissociate o o o pH measure of the concentration of dissolved H pH scale goes from 1 acidic to 14 basic pH log H 10 pH H Know what a buffer is and understand how buffers control pH o Buffers are substances that gain or lose protons depending on pH o If pH increases becomes more basic then the buffer will lose protons to make the solution more acidic control the pH If pH decreases becomes more acidic then the buffer will lose protons to make the solution more basic control the pH o Know the structure and general chemical activities of the major reactive groups on organic molecules OH hydroxyl basic hydrogen bonding CO CHO carbonyl hydrogen bonding NH2 amine basic hydrogen bonding COOH carboxyl acidic P04 phosphate charged and high energy bonds SH sulfhydryl reactive important in protein structure CH3 methyl non reactive and nonpolar o Hydroxyl OH alcohol polar o Carbonyl C O H C O ketone if the carbonyl group is within a carbon skeleton aldehyde if the carbonyl group is at the end of the carbon skeleton o Carboxyl O C OH has acidic properties because the covalent bond between the oxygen and hydrogen is so polar o o Amino H N H amines in amino acids acts as a base o Sulfhydryl SH thiols two sulfhydryl groups can react forming a covalent bond This cross linking helps stabilize protein structures Phosphate PO4 contributes negative charge to the molecule of which it is a part 2 when at the end of a molecule 1 when located internally in a chain of phosphates activity of proteins is often controlled by the addition or removal of phosphate groups bonds are high energy bonds and are often used as energy currency in cells ATP o Methyl CH3 addition of a methyl group to DNA or to molecules bound to DNA affects expression of genes Be able to distinguish carbohydrates sugars lipids and amino acids from their structural formulas Know what a monosaccharide disaccharide and polysaccharide are that glucose is a 6 carbon monosaccharide o Carbohydrates sugars and the polymers of sugars source of energy and carbon Monosaccharide single sugar molecular formulas simplest carb Disaccharide double sugars two monosaccharides Polysaccharide polymers composed of many sugar building blocks o Lipids o Amino Acids Know that glucose forms two important polysaccharides starch glycogen and cellulose Starch is used for energy storage and that cellulose is used in plants to build cell walls has a structural role o Starch plants store stockpiles of glucose in the form of starch in chloroplasts Two forms Amylose linear chain of 1 4 glycosidic linkages and amylopectin branced has additional 1 6 linkages o Cellulose major structural component of the tough wall of plant cells cellulose is a polymer of glucose but the glycosidic linkages differ from starch The difference is based on two ring forms for glucose alpha starch and beta cellulose Know the general structures of the three types of lipids Fats Phospholipids and Steroids and be able to state what their main biological functions are o Fats energy storage Fatty acids may be saturated all carbons have two attached H or unsaturated some carbon carbon double bonds Most animals are saturated These fats stack together to form solids butter Can clog arteries and cause cardiovascular disease Unsaturated fats are prevalent in plants and fish The inflexibility of double bond prevents them from stacking Thus they are liquid at room temperature o Phospholipids building membranes Two fatty acids and a phosphate group are attached to glycerol the fatty acid tails are hydrophobic but the phosphate group forms a hydrophilic head o Steriods are signaling molecules hormones They re lipids characterized by a carbon skeleton consisting of four fused rings Cholesterol implicated in cardiovascular disease it s a component in animal cell membranes and is the precursor to several steroid hormones Know that proteins are polymers of amino acids held together by peptide bonds that each kind of protein has a unique amino acid composition different order in which the amino acids are strung together that cells contain thousands of different kinds of proteins and that each protein has a specific cellular function o The different R groups have
View Full Document
Unlocking...