BIOL 120 1st Edition Exam 1 Study Guide Lectures 2 8 Lecture 2 1 What classifies an organism as living Consist of one or more cells Energy Utilization Have a metabolism used to grow and reproduce Sense and respond to their environment o Use homeostasis maintain internal environment Cellular Organizations o Microscopic atoms molecules organelles etc o Macroscopic tissues organs organism population community ecosystem biosphere Interdependency among organism o Trophic pyramid Reproduction Growth and Development Evolutionary Adaptations 2 Hierarchy of Living Systems Cellular level o Atoms molecules organelles cells Organismal level o Tissues organs organ system organism Population level o o o o o 1 Population a group of individuals of the same type in an area 2 Species all populations of a particular kind of organism 3 Community population of different species living together in one place 4 Ecosystem physical environment and the community living and nonliving 5 Biosphere Earth s region where organisms can exist 3 Scientific Enquiry Science aims to understand the natural world through observation and reasoning descriptive and precise Deductive reasoning uses general principles to make specific predictions Inductive reasoning uses specific observations to develop general conclusions Scientific method o Observation o Hypothesis formation o Prediction o Experimentation o Conclusion 4 Cells and Cell Theory Cell Theory all organisms are made of cells and all cells come from preexisting cells o Discovered by Louis Pasteur Cell a highly organized compartment bounded by a plasma membrane 5 Theory of Evolution Evolution a change in the characteristics of a population over time o Natural selection aids evolution o Phylogenetic tree a graphical representation of the evolutionary relationships among species o Natural selection acts on individuals evolution acts on a population o Two conditions must be met for natural selection in populations to occur Individuals must vary in characteristics Some of these characteristics must help individuals survive or reproduce more than other traits o Fitness the ability of an individual to produce offspring o Adaptation a trait that increases the fitness of an individual in a particular environment o Artificial Selection Repeating the selection process over generations results in changes in the characteristics of a domesticated population over time breeding Using molecules to understand the tree of live evolution o Uses DNA to make connections on the phylogenetic tree o 3 main groups Eukarya Plantae Fungi Animalia Protista Bacteria Archaea 6 Basic Atomic Structure Matter anything that occupies space and has mass solid liquid gas Element a substance that can t be broken down into another substance by chemical reactions Atomic number number of protons in the nucleus Atomic mass the number of protons and neutrons Isotopes an atom with the same number of protons but a different number of neutrons o i e Carbon has 6 p and 8n At Wt 14 and Carbon has 6 p and 6 n At Wt 12 Protons positively charged particles Neutrons neutral particles Electrons negatively charged particles Molecule a substance made from two or more atoms of similar or different types form when atoms bond to each other o Most important to life is water because it forms hydrogen bonds Energy the capacity to do work or supply heat and is either stored potential energy or active motion Chemical energy potential energy that is stored in chemical bonds ATP Thermodynamics o 1st law energy cannot be created or destroyed o 2nd law spontaneous natural processes increase entropy overall 7 Chemical Bonds Atoms gain or lose electrons in order to be stable o Valence electron electrons in the outermost shell o Valence number of unpaired electrons in an atom Chemical reaction when an atom gives up gains or shares one or more electrons with another atom Covalent Bond each atom s unpaired valence electrons are shared by both nuclei to fill their orbital o Non polar equal electronegativity o Polar unequal electronegativity o Ionic bond results from the attraction of a cation and anion o Ion an atom or molecule that carries a charge from either losing or gaining an electron o Cation an atom that loses an electron and becomes positively charged o Anion an atom that gains an electron and becomes negatively charged 8 Representing Molecules Molecular formula indicate the numbers and types of atoms in a molecule Structural Formula indicate which atoms are bonded together and whether the bonds are single double or triple Ball and Stick models and space filling models shows D geometry o 9 Water Most important chemical property can form hydrogen bonds A great solvent due to the covalent bonds being polar it can bond to other atoms Hydrogen bonds the weak electrical attractions between the partially negative oxygen of one molecule and the partially positive hydrogen of a different water molecule o Hydrophilic can dissolve water loving i e sugar o Hydrophobic uncharged and nonpolar compounds that repel from water i e oil fat Properties o Water is Cohesive binding between like molecules o Adhesive Binding between unlike molecules o Denser as a solid than a liquid expands as it changes from a liquid to a solid o Ability to absorb large amounts of energy 10 Reactions pH o expresses proton concentration in a solution Pure water 7 Acids 7 a substance that increases H concentration in a solution add Carbonic acid to bases as a buffer Bases 7 a substance that reduces H concentration of a solution Add bicarbonate to acids as a buffer o pH scale change in one unit of pH 10X change in H concentration Chemical Reactions o Chemical equilibrium occurs when the forward and reverse reactions proceed at the same rate and the quantities of reactants and products remains constant o Endothermic reaction need to absorb heat to react o Exothermic reaction release heat during a reaction o Redox during some chemical reaction electrons can be transferred from one atom to another while still retaining the energy of their position in the atom a Oxidation loss of an electron b Reduction gain of an electron 11 Energy Energy the capacity to do work or supply heat Potential energy stored energy an object s position determines its ability to store energy Kinetic thermal energy the energy of movement that is measured as a temperature Heat the thermal energy transferred between objects of different temperatures Gibbs free energy change G determines whether a