Study Guide Exam 1 BIO 301L Chinnery Spring 2013

Transcription

1 Study Guide Exam 1 BIO 301L Chinnery Spring 2013 Lecture 1: Biology and Life What are the big picture messages from this lecture? How can you associate the contents of this lecture with those of the other lectures? Be able to list the ten features shared by all life forms. 1.) made of organized parts 2.) made of cells (smallest level of life) 3.) reproduce 4.) perform chemical reactions (digesting) 5.) regulate internal conditions (homeostasis) 6.) mature (grow) 7.) evolve in groups (occurs over a long time) 8.) come from same ancestry (all come from same origin) 9.) obtain energy from surroundings (eating food) 10.) respond to the environment Know the levels of the organization of life, in order from either most to least or least to most inclusive. Least>most 1.) (molecule) 2.) cells 3.) tissue 4.) organ 5.) organ system 6.) organism 7.) population 8.) community 9.) ecosystem inclusive>include more What are the two ways that science is done? Which uses deductive reasoning, and which uses inductive reasoning? 1.) Discovery science-scientists describe some aspect of the world & use INDUCTIVE (specific) reasoning to draw general conclusions o ex. naming a dinosaur 2.) hypothesis-based science-scientists attempt to explain observations by testing hypothesis o uses DEDUCTIVE reasoning o narrow down to a certain conclusion through series of experiments

2 What are the two important qualities of hypothesis-based science? 1.) hypothesis must be testable 2.) hypothesis must be falsifiable (can prove it wrong) What is a theory, and how many tests have to not falsify a hypothesis before it becomes a theory? Theory-broad in scope; generate hypotheses; supported by massive body of evidence o Ex. Einstein s theory of relativity o Ex. Darwin s theory of evolution o Ex. Lemaitre s big bang theory of the universe A hypothesis becomes credible when repeated attempts to disprove it fail Hypothesis becomes a theory when it is proved practically w/ experiments Theory happens when it is both explained scientifically and proven experimentally Theory more like a scientific law o Explanation of a set of related observations based upon proven hypotheses and verified multiple times Scientist can t create a theory; only a hypothesis Be able to make a hypothesis that could be tested based on a scenario. Hypothesis-educated guess or tentative answer to a problem or question. Ex. what is wrong with this light bulb? Hypothesis: The batteries are dead in the light bulb. Prediction: Changing the batteries will make the bulb work Test Lecture 2: Basic chemistry What are the big picture messages from this lecture? How can you associate the contents of this lecture with those of the other lectures? What are the three states of matter, and how are they classified? 3 physical states: solid, liquid, gas matter-anything that takes up space and has mass molecules constantly moving gas moves fast; liquid a bit slower; solid slower but still moving classified: o 1.) element-substance composed of only one type of atom (ex. can have a lot of carbon atoms in it)! on the periodic table o 2.) molecule-unit composed of 2 or more atoms of an element joined together by chemical bonds! can be same or diff atoms (ex. O2 or H20)

3 ! but mostly same o 3.) compound- a type of molecule just that different types of atoms form this! substance composed of 2 or more different chemical bonds (ex. H20, C02, or Ch3 or NaCl) o 4.) mixture: combo of 2 or more substances that don t chemically bond! ex. sugar mixed w/ salt! parts of a salad Be able to list the four most essential elements to life. Carbon (18.5%) Oxygen (64.7%) Nitrogen (3.3%) Hydrogen (9.5%) Together these make up 96% of living matter Only about 25 of the elements are essential to life What are the three subatomic particles in an atom, what are their charges, and which of them determine how the atom will behave around other atoms? Protons (pos electrical charge) (inside nucleus) Neutrons (no electrical charge) (inside nucleus) Electrons (neg electrical charge) (outside nucleus) Element atomic # is # of protons Mass # sum of proton plus neutrons in nucleus Electrons determine how the atom will behave around other atoms o Outer orbital (valence shells) dets reactivity of atom) Electron orbit nucleus in orbitals How many electrons are in the first electron shell, and how many in the other shells? 1 st shell: max 2 electrons 2 nd & 3 rd shells: max 8 electrons max 7 shells What happens when an atom has an outer electron shell that is not completely full? If outer shells are full then most stable If not full, then element usually lose or gain their electrons to or from other elements o But don t lose electrons, they loan it & hook up to another atom o Ex. Na gives up electrons (1 electron outside) o Ex. Cl takes electrons (7 electrons outside) o Ex. O2 shares electrons (4 electrons outside) Noble gases: full outer shells What are the two types of energy, and what does the First Law of Thermodynamics state? 1.) potential energy-stored energy

4 2.) kinetic energy-energy constantly causing change (energy of motion) a change always requires energy o energy can also be converted from one form to another 1st law of thermodynamics- energy can t be created or destroyed; can only be transferred or transformed What are chemical reactions? Know the four types of chemical reactions we discussed in class. Chemical reactions- changes in the chemical composition of matter o Help atoms to give up or acquire electrons in order to complete their outer shells o Reactions can be written as equations Chemical reactions: o 1.) combo/synthesis reactions! occurs when 2 or more substances react to form a product! Na + Cl > NaCl o 2.) decomposition reactions! when one substance undergoes a reaction to produce 2 or more substances! 2H2O > 2H2 + O2 o 3.) exchange reaction! occurs when molecules swap partners! NaOH + HCl > NaCl + H2O o 4.) reversible reactions! these can go forwards (decomposition) or backwards (combo)! H2CO3 > < CO2 + H2O Be able to tell where in a chemical equation the reactants are and where the products are, and how many of each type of atoms or molecules are present. Reactants on other side of arrow (interacting participants) Products on the opposite side of arrow (substances generated) If says 2H2 + O2 > 2H2O o Then 2 H2 molecules present, one O2 molecule present o 4 Hydrogen atoms (2x2), 2 Oxygen atoms if says 2(NH4)3 (3 is a subscript) o then 6 N atoms (3 x 2) o and 24 H atoms (4 x 3= 12 x 2= 24) Be able to describe the four types of bonds we discussed: ionic, covalent, polar covalent, and hydrogen bonds. Which is strongest? Which allow molecules to interact with other molecules? Ionic: attraction between an anion and a cation (oppositely charged ions) o Anion neg charged o Cation pos charged o Transfers one or more of tis electrons completely to another o Bonds two atoms

5 o An ion is pos if have less electrons in outer shell; neg if have more o Ex. sodium low electronegativity o Ex. chlorine high electronegativity o Ionic bonds dissolve well in water b/c hydrogen bonds in water bond w/ the salt and dissolve it Covalent: when 2 atoms share one or more pairs of outer-shell electrons (valence electrons) o Usually bond w/ 2 of same atoms o Ex. H2, O2 o Sharing of electrons between same molecule will be equal but not necessarily for different ones! When not equally shared called polar bonds Polar covalent: diff parts of the molecule have slightly different charges o Ex. H2O o Not sharing the electrons equally between oxygen and hydrogen o Unequal sharing makes water a polar molecule (diff charges on each side) o Oxygen has a more neg pull as opposed to the positive H s b/c it s bigger Hydrogen bonds- forms when H atom covalently bonded to one atom in a molecule is also attracted to another atom in another molecule (for ex. attracted to N) o Each molecule has covalent bond w/ distinct pos & neg sides making it polar o The partners are usually nitrogen or oxygen o Easiest to break (least strong bond) Covalent bonds are the strongest o Hydrogen weakest; ionic in the middle o Hydrogen> ionic> covalent Hydrogen bonds allow molecules to interact w/ other molecules Ionic bonds tend to break down in water, and the ions then stay separated from each other. Based on what you know about the properties of water, why would this be so? This explains the presence of H + ions in acids. Reason why ionic bonds break down in water is b/c of the hydrogen bonds in water that attract to the ionic bonds, break them apart, and thus make them dissolve o Ex. salt (NaCl) dissolves well in water How do you determine how acidic a solution is? What is the correlation between the ph scale numbers and the amount of H + ions in a solution? See how many H+ ions are floating around by themselves o If a lot then more acidic acids have more H+ ions and more neg ions (anions) o donates H+ ions to solutions hydroxide ions floating around called bases base- more pos ions (cations) and more hydroxide ions (OH-) o accepts H+ ions and removes them form solution, reducing the hydrogen ion concentration of a solution (make less acidic) ph-measure of concentration of H+ ions in solution