BIO 101 1st Edition Exam 1 Study Guide Chapters 1 5 7 Lecture 1 August 22 Biology the Study of Life Unifying Themes of Biology focus on Cell Theory 1 Life is organized on many structural levels increased complexity as you move up levels 2 Emergent properties new properties emerge when you move up in complexity 3 Cellular basis of life cell theory a All living things are made of cells b All cells come from other cells 4 Heritable information a DNA is the genetic information in cells b The information in DNA flows in 2 ways i Parent offspring ii DNA RNA proteins The study of how DNA is passed to offspring is called genetics 5 Correlation of structure and function what a molecule looks like determines what it can do 6 Unity in diversity all living thing share certain traits like a genetic code Lecture 2 August 27 Atoms Molecules and Chemical Bonds Atomic number and atomic mass how they are symbolized and how to determine the number of protons neutrons and electrons from it Atomic number is the number of protons in an atom Atomic mass is the number of protons and neutrons in an atom how much the atom weighs Ex 12 superscript represents atomic mass C 6 subscript represents atomic number Protons determined by subscript Neutrons Mass atomic number Electrons same as protons Valence Electrons Valence electrons are the number of electrons needed to fill the outermost shell This number represents the number of covalent bonds the element must form to be stable For example Hydrogen has only one electron in its outer shell It would need another electron to fill its shell so Hydrogen would need to form one covalent bond to be stable BIO 101 1st Edition The Chemical behavior of atoms depends on the number of bonds it needs to form The valences of the 4 major elements H O N C are important to all living things element valence H 1 O 2 N 3 C 4 Strong Bonds what is the difference between a covalent and ionic bond What is the difference between polar and nonpolar covalent bonds and how does it affect the behavior of the molecules formed Covalent bonds are chemical bonds formed by sharing electrons Ionic bonds are chemical bonds formed by the attraction between two atoms and then a complete transfer of electrons from a donor atom to an acceptor atom Nonpolar covalent bond 2 atoms share a pair of electrons equally the atoms have similar or identical electronegativity Polar covalent bond 2 atoms share electrons unequally one atom has a greater electronegativity which leaves the other atom a little bit positively charged Weak Bonds hydrogen and hydrophobic Hydrogen bond a weak charge attraction between a partially H atom of one molecule and a partially atom of another molecule There is no electron sharing or transfer with a 1 20 strength of a covalent bond Hydrophobic bond tendency of nonpolar molecules to avoid H2O which is a polar substance and thus associate with each other What is a hydrogen bond Use water as an example be able to draw a picture with an arrow showing the position of the hydrogen bond A hydrogen bond is a weak charge attraction between a partially H atom of one molecule and a partially atom of another molecule What does electronegativity mean Electronegativity is the ability to attract electrons How does polarity affect the behavior of molecules If a bond is polar then one atom in the bond the one that hogs the shared electrons is a little bit negatively charged That leaves the other atom a little bit positively charged BIO 101 1st Edition Lecture 3 August 29 Water H2O What are the unique characteristics of water What are examples of the importance of these characteristics in living systems 1 High Specific Heat amount of heat required to increase the temperature of a substance by 1 degree C a With H2O heat goes first to break H bonds little change in temperature b If it takes out heat H bonds form releasing heat again there is little change in temperature Most living organisms are made up of mostly water and so it helps organisms resist dramatic changes in temperature It also helps stabilize ocean temperature protecting marine organisms 2 Water expands when H freezes ice floats on liquid water a H2O is one of only a few substances where the solid form is less dense than the liquid forms b In liquid H2O H bonds form and break as the molecules move around c When they reach 0 degrees C the molecules are no longer moving fast enough to break the H bonds and they become locked into a crystal lattice where each H2O is bonded to the maximum number of partners held father apart from each other 3 Water is the Biological Solvent a H2O is the solvent in living organisms b The cell is like a tiny drop of H2O with many molecules solutes dissolved in it c H2O is a good solvent for charged or polar substances but nonpolar substances do not dissolve in H2O because polar and nonpolar substances do not mix What is it about water that causes most of its unusual properties The unusual behavior of water is due to its hydrogen bonding Water is a polar molecule because of the polar covalent bonds between O and H Water molecules are attracted to one another due to charge attraction Properties of Water Solution Molarity and pH Know the definitions and be able to apply to simple problems Know how to make a solution of a given Molarity know how to figure out the number of molecules in a solution of given molarity review sample problems on BlackBoard Be able to determine pH given either the H or the OH Mole number of grams of a substance equal to its molecular weight in Daltons Molar number of moles of a solute in 1 liter of solution the concentration pH log H pH pOH 14 H OH 10 14 One unit change in pH is a 10 fold change in H For example if the pH goes from 6 to 7 there is a 10 change BIO 101 1st Edition Lecture 4 September 3 Carbon and Molecular Diversity Know some reasons why Carbon is the element of life Carbon is small and forms strong bonds 4 covalent bonds It is versatile in bonding can bond to other carbon atoms or several other elements It can form large complex and diverse molecules which is important for living things It can be used to make many kids of molecules that have different functions Terms organic and hydrocarbon What is a hydrocarbon and why are these molecules nonpolar Organic molecules that contain carbon Hydrocarbon molecules containing only C and H Hydrocarbons are nonpolar because the bonds between C and H are nonpolar covalent bonds because their electronegativity is about the same