Week 1 Notes
Week 1 Notes BIOL 101 - 001
Popular in Biological Principles I
HIST 1100 - 01
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This 6 page Class Notes was uploaded by Caroline Colleran on Monday August 31, 2015. The Class Notes belongs to BIOL 101 - 001 at University of South Carolina taught by Vicki S Vance (P) in Fall 2015. Since its upload, it has received 130 views. For similar materials see Biological Principles I in Biological Sciences at University of South Carolina.
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Date Created: 08/31/15
BIOLOGY 101 VANCE Introduction CHAPTER 1 Biology study of life Unifying themes in biology help to organize all of the information helps to remember it and to think about it 1 Life is organized on many structural levels a Start at the simplest level increasing complexity b Atoms l molecules l macromolecules l cell structures l cells l tissues l organs l whole organism l populations l communities ecosystem 2 Emergent properties as you move up in complexity new properties emerge 3 Cellular basis of life cell theory 2 parts 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 ows in 2 ways 1 parent I offspring gt it is DNA that moves from parent to the offspring 2 DNA l RNA l proteins c DNA has the code for how to make proteins It is the proteins that determine what an organism is and what it can do 5 Correlation of structure and functions a What a molecule looks like determines what it can do 6 Unity in diversity 15 million species identi ed estimated 30 million species exist HUGE DIVERSITY a Unity in life yet all living things share certain traits i Ex Genetic code same in all living things ii Glycolysis series of chemical reactions that use food to produce readily useable energy Theory of Evolution greatest unifying theme in biology Explains both diversity and unity in life BIOLOGY 101 VANCE CHAPTER 2 Atoms molecules and chemical bonds Unity because all living things today are connected because they came from a common ancestor in the ancient past Diversity because living things have changed to t a particular environment 825 Matter elements amp compounds anything that takes up space and has mass a Element can t be broken into other substances by ordinary chemical means 92 naturally occurring elements i 25 elements required for life ii 4 elements make up 96 living matter Carbon Oxygen Hydrogen Nitrogen b Compound molecules made up of more than one element in a xed ratio i Ex NaCl sodium chloride Structure amp Behavior of Atoms a Atom smallest possible amount of an element b All atoms of an element are alike c Each element has its own kind of atoms i Ex C and H atoms are different from one another d Atomic Number of protons in an atom e Atomic mass of protons of neutrons how much it weighs f Isotopes atoms of an elements that have different atomic mass but some atomic different number of neutrons i Some are unstable radio isotopes ii Release energy as they break down iii They can be useful Electrons amp Energy Levels a Where electrons are found orbiting nucleus of atom at discrete levels positions called shells b Electrons ll up closest shell rst 2 electrons c Outer shells lled in order next one holds 8 d If atom doesn t have enough electrons to ll all shells only outermost shell is partly empty e Octet Rule all atoms have tendency to ll up the outer shell i Ex Noble elements f Chemical properties of an element depend on of electrons in outermost shell Chemical Bonds attractions that hold atoms together a Molecule 2 or more atoms held together by chemical bonds BIOLOGY 101 VANCE b Valence bonding capacity of an atom of bonds an atom must form to be stable of electrons needed to ll outermost shell STRONG BONDS A Covalent Bonds a chemical bond formed by sharing electrons STRONG BOND a 2 Kinds nonpoar covalent bonds amp polar covalent bonds b Nonpolar Covalent Bonds bond formed when two atoms with similar or identical electronegativity share a pair of electrons c Electronegativity ability to attract electrons i NaltHltCltNCltO ii Low ability to attract electrons high ability to attract electrons d Nonpolar Bond 2 atoms share a pair of electrons equally because about the same ability to attract the shared electrons e Polar Covalent Bond share electrons unequally i One atom has greater electronegativity it hogs upquot the electrons and therefore is a little bit negatively charged ii Other atom is cheated out of shared electrons much of the time and therefore is a little bit positively charged iii Usually nd POLAR COVALENT BONDS in molecules involving H with O N Cl iv Ex H20 f Single covalent bonds atoms share 1 pair of electrons g Double covalent bonds atoms share 2 pairs of electrons h Triple covalent bonds atoms share 3 pairs of electrons B Ionic Bonds bond formed by electrostatic attraction between two atoms after a complete transfer of an electron from a donor atom to an acceptor atom STRONG BOND aExNaCl V Chemical Reactions the breaking and forming of chemical bonds described chemical equations that tell what atoms are involved how many which way reaction goes a Most biologically important reactions are reversible and reach an equilibrium WEAK BONDS Some are important for Biology BIOLOGY 101 VANCE A Hydrogen Bond weak charge attraction between a positive H atom of one molecule and a negative atom of another molecule a Ex H20 no electron sharing i No electron transfer ii Weak bond iii 120 strength of covalent bond iv continually breaking and forming B Hydrophobic Bond tendency of nonpolar molecules to avoid H20 a polar substance and thus associate with each other a Ex Important in membrane structure Chapter 3 Water Life began as water all organisms made up mostly of water 34 of Earth is made up of water The abundance and unusual behavior of H20 is the major reason the earth is habitable The unusual behavior is due to hydrogen bonding H20 is a polar molecule due to polar covalent bonds between 0 and H charge on H H charge on O H20 molecules are attracted to one another and to other polar or charged molecules due to charge attraction Unusual properties of H20 are an example of EMERGENT properties due to an increase in level of structural organization caused by H bonding Unusual Properties of Water H20 a High Speci c Heat amount of heat in calories required to increase the temperature of a substance by 1 degree Celsius i With H20 heat goes rst to break Hbonds therefore little change in temperature ii If you take out heat Hydrogen bonds form releases heat little change in temp iii Biological signi cance of high speci c heat 1 Living organisms are made up mostly of H20 and can therefore resist dramatic changes in temperature 2 This tends to stabilize ocean temperatures and protect marine organisms b H 20 expands When it freezes therefore ice oats on liquid water i H20 is one of only a few substances where the solid form is LESS dense than the liquid forms ii Due to Hbonding between H20 molecules BIOLOGY 101 VANCE iii In liquid H20 Hbonds form and break often as the molecules move around iv At 0 degrees Celsius the molecules are no longer moving fast enough to break Hbonds the H20 molecules become locked into a crystal lattice where each H20 is bonded to the maximum of partners held farther apart from each other less dense v Biological signi cance of ice oating oating ice insulates the liquid water below prevents lakes and oceans from freezing solid allows survival of water organisms during winter c Water is the Biological Solvent i Solution liquid which is a homogeneous mix of 2 ore more substances 1 Solute substance that is dissolved 2 Solvent the dissolving agent ii H20 is the solvent in living organisms iii The cell is like a tiny drop of H20 with many molecules solutes dissolved in it iv The characteristic properties of H20 as a solvent are due to Hbonding v H20 is a good solvent for charged or polar substances opposite charges attract vi ex NaCl easily dissolves in H20 the polar H20 molecules pull the 2 ions apart and surround them n E EJ39I Ea ii mi quot r 1 If L r 1 1 39t g at i x ft L l a i I x l u n J Lu ll1 395 M ml 1 Equot L6quot quot39 i i 39t if rial L it vii Nonpolar substances do NOT dissolve in H20 polar and nonpolar substances do not mix like oil and H20 oil is nonpolar and H20 is polar ll Properties of Aqueous Solutions solutions where H20 is the SOLVENT cells are aqueous solutions so it is important to understand the properties of aqueous solutions we will discuss two properties of H20 solutions A Solute Concentration of molecules in a given amount of solution a Moe of grams of a substance equal to its molecular weight BIOLOGY 101 VANCE b Molecular Weight sum of the atomic masses of each atom in the molecule Molar of moles of a solute in 1 liter of solution The concentration of substances in living cells is usually given in terms of molar1y This is because molarity gives information about the of molecules f One mole of ANY substance has the same number of molecules as one mole of any other substance 6022gtlt1023 molecules i y 2 r in H B Acids Bases and pH at 11 if Hmw DH a The H20 molecule can dissociate b This happens rarely c Though rare it is important because small changes in H and OH can cause dramatic changes in the ability of biological molecules to function d In pure H20 the H OH they are in balance e When acids or bases dissolve in water it shifts the balance of H and OH f In pure H20 H OH 10 7 00 D