BIOL 1107 1nd Edition Exam 1 Study Guide Lectures 1 10 Each section below includes material from the lecture homework and textbook Lecture 1 August 20 Chapter 2 The Chemical Context of Life Molecular Interactions ionic hydrogen bonding covalent van der Waals London dispersion Ionic the attraction between cations and anions which have opposite charges Two atoms are so unequal in their attraction for valence electrons that the more electronegative atom strips an electron completely away from its partner A charged atom or molecule is called an ion Example The electron transfer between two atoms moves one unit of negative charge from sodium to chloride Therefore sodium now 11 protons and 10 electrons has a net electrical charge of 1 Positive charge cation mnemonic CAT PAWsitive Negative charge anion Compounds formed by ionic bonds are called ionic compounds or salts Hydrogen bond noncovalent attraction between a hydrogen and an electronegative atom In living cells electronegative partners are usually oxygen and nitrogen atoms Hydrogen bonds b n water molecules allow some insects to walk on water Covalent sharing of a pair of valence electrons by two atoms One of the strongest bonds Two or more atoms held together by covalent bonds constitute a molecule Van der Waals London dispersion weak bonds that occur only when atoms and molecules are very close together These bonds are responsible for the ability of a gecko lizard to walk up a wall Van der Waals interactions hydrogen bonds ionic bonds weaker bonds Lecture 2 August 22 Chapter 4 Carbon and the Molecule Diversity of Life Carbon forms backbone of proteins lipids and sugars in body Enters biosphere through the action of plants which use solar energy to transform atmospheric carbon dioxide into the molecules of life These molecules are passed along to animals that feed on plants Organic chemistry study of carbon compounds Forms lots of diverse structures including long chains branched rings complex rings Rings glucose carbon and oxygen major backbone Carbon usually completes its valence shell by sharing its 4 electrons with other atoms in covalent bonds so that 8 electrons are present Bonds may include single bonds and double covalent bonds C C bonds are as strong as C O bonds C is the only element that bonds with its own kind about as strongly as it bonds with other elements Hydrocarbons organic molecules consisting of only carbon and hydrogen Are major components of petroleum which is called a fossil fuel because it consists of the partially decomposed remains of organisms that lived millions of years ago Not prevalent in living organisms however many cell s organic molecules have regions consisting of only carbon and hydrogen Ex fats have long hydrocarbon tails attached to a non hydrocarbon component Neither petroleum nor fat dissolves in water both are hydrophobic Why are they insoluble in water Because the great majority of their bonds are relatively nonpolar carbon to hydrogen linkages Hydrocarbons can undergo reactions that release a relatively large amount of energy Isomers compounds that have the same numbers of atoms of the same elements but different structures and hence different properties Structural isomers differ in covalent arrangements of their atoms Geometric isomers GI have the same covalent partnerships but they differ in their spatial arrangements For GIs differences arise from the inflexibility of double bonds Single bonds allow atoms they join to rotate freely about the bond axis without changing compound however double bonds do not permit such rotation Functional Groups chemical groups that affect molecular function by being directly involved in chemical reactions Lecture 3 August 25 Chapter 5 The Structure and Function of Large Biological Molecules Organic molecules can be very large and have thousands of functional groups Polymer long molecule consisting of many similar or identical building blocks linked by covalent bonds much as a train consists of a chain of cars Repeating units that serve as building blocks of a polymer are smaller molecules called monomers Synthesis of polymers condensation dehydration reaction monomers are connected by a reaction in which two molecules are covalently bonded to each other through loss of a water molecule Breakdown of polymers hydrolysis reverse of dehydration reaction Bonds between monomers are broken by addition of water molecules with a hydrogen from water attaching to one monomer and a hydroxyl group attaching to adjacent monomer Example of hydrolysis process of digestion bulk of organic material in food form of polymers are attacked by various enzymes which speed up hydrolysis process Carbohydrates include both sugars and polymers of sugars Simplest carbs monosaccharides aka simple sugars Disaccharides double sugars consist of two monosaccharides joined by covalent bond Polysaccharides polymers composed of many sugar building blocks Used in cell membranes Plants cell walls plants store carbs for rigidity and structure Really important in your joints keeps it lubricated What does a carbohydrate look like Can be hydrophilic phobic polysacch s are hydrophobic glucose and other monosacch s hydrophilic because sugar can dissolve in water Monosaccharides generally have molecular formula of the unit CH2O Glucose most common monosaccharide Trademarks of sugar can be seen in structure of glucose a carbonyl group and multiple hydroxyl groups Depending on the location of carbonyl group sugar is either aldose aldehyde sugar or ketose ketone sugar Glucose aldose Fructose ketose Diversity of simple sugars size of carbon skeleton range 3 to 7 carbons long spatial arrangement of their parts around asymmetric carbons carbon attached to four different atoms or groups of atoms Monosaccharides particularly glucose are major nutrients for cells Cellular respiration cells extract energy in series of reactions starting w glucose Simple sugar molecules major fuel for cellular work carbon skeletons also serve as raw material for synthesis of other types of small organic molecules such as amino acids and fatty acids Disaccharides consists of two monosaccharides joined by glycosidic linkage covalent bond formed b n two monosaccharides by a dehydration reaction Maltose glucose glucose Sucrose glucose fructose Plants generally transport carbohydrates from leave to roots and other nonphotosynthetic organs in the form of sucrose Lactose glucose galactose Polysaccharides macromolecules polymers