BIO 151 1st Edition Lecture 3 Outline of Last Lecture 1. What about cells?2. The Cell Theory (Mid 1800s)3. Why would species evolve?4. Is the theory of natural selection correct?5. Cells are mostly water6. Ions and ionic bonds7. Water propertiesOutline of Current Lecture 1. What is in the water in living cells?2. Carbon-containing organic molecules3. Structural question: will an organic molecule dissolve in water?4. Hydrophobic interactions5. Chemical bonds6. Carbon-containing "organic" molecules7. Examples of chemical reactions8. Molecules contain potential energy in bonds, electrons9. What makes a reaction "spontaneous" (favored)?10. Enzymes - biological catalysts (speed chemicals reactions)Current Lecture - 1/26/15Organic Molecules, Electrons, Energy, and Enzymes -What is in the water in living cells?:- ions (including water ions), minerals - similar to sea water- carbon-containing compounds = organic molecules- covalent bonds are formed by sharing electrons between 2 atoms - atoms want to share enough electrons to fill their outer valence shell- innermost shell: full = 2- outermost shell: full = 8- organic molecules can make long chains with carbon-carbon bonds (single bonds or double bonds)Carbon-containing organic molecules:- structure (and movement)- reacts to make other moleculesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- energy storage in bonds, electrons- control of chemical reactionsStructural question: will an organic molecule dissolve in water?:- oxygen or nitrogen will polarize bonds = hydrophilic (likes water)- hydrocarbon chains (with just carbon and hydrogen) are nonpolar = hydrophobic (scared of water)Hydrophobic interactions:- water likes water, pushes hydrophobic molecules (or parts of molecules) awayChemical bonds:- strong: covalent bonds (sharing electrons)- weak:-hydrogen bonds (electrical attraction between polarized molecules)-van der Waals interactions-hydrophobic "bonds" - hydrophobic molecules "hide" together, away from waterExamples of chemical reactions:- the breakdown of sugar- the synthesis of sugar- First Law of Thermodynamics - the total energy of an isolated system is constant; energy can be transformed from one form to another, but cannot be created or destroyed.- Second Law of Thermodynamics - there is an increase in the sum of the entropies (disorder) of the participating systems. Molecules contain potential energy in bonds, electrons:- kinetic energy = energy of motion- potential energy = the stored ability to cause motion-break bond = released potential energy becomes kinetic molecular motion = heat, or can be used to make another chemical bond.What makes a reaction "spontaneous" (favored)?:- depends on temp., the release of energy from bonds, changes in entropy = changes in Gibb's Free Energy (delta G)- spontaneous reactions release free energy (-delta G) = exergonic- non-spontaneous reactions absorb free energy (+delta G) = endergonic- Energy of activation is lowered through the use of an enzyme- required to form an "active" intermediate in the reaction- not stored - used, then released by the reaction- catalyst - compound that lowers activation energy needed for reaction-allows intermediate action to allow at lower temp. Enzymes - biological catalysts (speed chemical reactions):- 1st was Diastese (Greek for "separation") from barley - speeds starch into sugar (1833)- Pasteur: "ferments" in living cells- Buchner - enzymes can act outside living cells - 1907 Nobel Prize- different enzymes for different chemical reactions- named "xxx-ase"- "lock and key" binding between molecules -bonding usually based on many non-covalent bonds - ex. hydrogen bonds,
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