o Polar solutes dissolve in polar solvents o Non polar solutes dissolve in nonpolar solvents Smallest unit of matter that retains all of the properties of that element Organisms are composed largely of 11 basic elements Nitrogen Oxygen Biology 1201 Lecture Notes Dr Wischusen Week 1 8 25 8 29 What determines solubility Like dissolves like Like in terms of polarity Atom Atomic mass of protons of neutrons Atomic Number of protons Subatomic Particles o Proton 1 dalton 1 charge o Neutron 1 dalton 0 charge o Electron 0 dalton 1 charge Why is atomic structure biologically important Carbon Potassium Sodium Chlorine Value for an average human 1000 00 The difference between chemicals and me o the organization Scale of Nature What are Biologists most interested in o Atomic 10 8 m o Community Ecosystem 106 m Approaches to Biology Reductionist Wholist o Whole system in a whole form Isotopes some atomic but different mass o Reduces some processes problems down to understand individually o Biol 1201 1202 uses this approach Valence of electrons that need to be gained or lost to fill the outer shell of electrons Also predicts the number of bonds that an atom will form Valence electrons the electrons in the outermost shell What determines polarity of a molecule Chemical bonds Ionic Bonds Covalent Bonds o Form when atoms gain and lose or share electrons o They are the result of electrical attractions b w atoms o Form when completely gain or lose electrons o Strongest bonds when dry o Form when atoms share electrons o If shared equally covalent o If shared unequally polar covalent o Strongest bond in water Weak bonds Hydrogen bonds o Bonds which are not involved in making a substance o Weak attractions b w atoms on different molecules or different molecules or different parts of a large molecules o Occur b w molecules that have polar covalent bonds o Always involve hydrogen UHH DUH o Refer to figure 2 13 in textbook Molecules and Compounds o Compound o Molecule A substance consisting of two or more different atoms in specific proportions bonded together in a specific pattern The smallest unit of a compound that retains all of the properties of that compound Molecular Formulas Water H2O Carbon Dioxide CO2 Glucose C6H12O6 Isomers atoms Molecules w the same molecular formula but a different arrangement of Molecular Weight Gram Molecular Weight The sum of the atomic masses for all of the atoms in a molecule H2O 1x2 16 18 daltons The mass of a substance equal to its molecular weight in grams Contains a constant number of molecules Avogadro s of molecules o 6 022 X 1023
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