BIOS 208 1st Edition Lecture 11 Outline of Last Lecture I. CholesterolII. Protein FunctionsIII. Amino acidsIV. Amino Acid PolymersV. Protein StructureVI. Sickle-Cell Disease: A Change in Primary StructureVII. Nucleic Acids VIII. Nucleotide Polymers IX. Structures of DNA and RNA MoleculesOutline of Current Lecture I. DNA and Proteins as Tape Measures of Evolution II. MetabolismIII. Forward Reaction and Reverse ReactionIV. Thermodynamic LawsV. Kinetic and Potential EnergyVI. Free-Energy ChangeVII. Units of EnergyVIII. Order as a Characteristic of LifeCurrent LectureI. DNA and Proteins as Tape Measures of Evolution A. The nitrogenous bases in DNA pair up and form hydrogen bonds: adenine (A) always with thymine (T), and guanine (G) always with cytosine (C)B. Called complementary base pairing.C. Complementary pairing can also occur between two RNA molecules or between parts of the same molecule.These 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.D. In RNA, thymine is replaced by uracil (U) so A and U pairE. The linear sequences of nucleotides in DNA molecules are passed from parents to offspring.F. Two closely related species are more similar in DNA than are more distantly related species.G. Molecular biology can be used to assess evolutionary kinship.II. MetabolismA. Cells are like small chemical industries.B. Each cell contains thousands of interrelated reactions which are regulated events catalyzed by enzymes.C. Metabolic pathways occur where there are central sets of reactions.D. e.g. a process called Glycolysis breaks down sugars, and the Krebs cycle enables conversion to energy by respiration.E. Molecular traffic occurs through cells, often with similar metabolic pathways in different organisms.F. Involves:a) Making and breaking covalent bonds.b) Getting, using, and changing the form of E (energy).c) Reactions are catalyzed by enzymes.d) Several enzymes may be organized into a pathway.III. Forward reaction and Reverse ReactionA. Respiration (in mitochondria).B. Catabolism (degrade to simpler forms).C. Exergonic (E released).D. Glucose + O2 >>>> CO2 + H2O + E Forward reaction.E. CO2 + H2O + E >>>> Glucose + O2 Reverse reaction.F. Photosynthesis (in chloroplasts) light energy stored in chemical bonds.G. Anabolism, build up to make complex molecules from simple ones.H. Endergonic (E required).I. Catabolism and anabolism drive one another.IV. Thermodynamic LawsA. 1st Law: E cannot be created or destroyed. Different forms of E can be interconverted.B. 2nd Law: During E inter-conversions, some E is always lost as random thermal movementor heat, which is not available to do work. The universe is a closed system.C. The entropy = randomness, disorder or chaos of the universe is always increasing. Living organisms are open systems (E in/out) and “islands” of high order/low entropy.V. Kinetic and Potential EnergyA. Ultimately all energy potential and kinetic is converted to heat energy. B. The example shown of a kid on a slide demonstrates gravitational potential energy being converted to kinetic energy and heat via friction.C. Energy is the capacity to do “work”…changing the organization of matter.D. Potential energy is related to the location of molecules.E. Water in a reservoir (dam) has potential energy due to gravity.F. Chemical bonds in a sugar…e,g. the breakdown of glucose can release potential energy stored in bonds.G. Kinetic energy is used in the process of doing “work”..e.g. falling water drives turbines toproduce electricity.VI. Free-Energy ChangeA. Some reactions occur spontaneously and others require input of energy .B. To see which are spontaneous and which require energy, energy changes that occur in chemical reactions have to be determined. C. A living system’s free energy G is energy that can do work when temperature and pressure are uniform, as in a living cell.D. The change in free energy (∆G) during a process is related to the change in enthalpy, or change in total energy (∆H), change in entropy (∆S), and temperature in Kelvin (T)a) ∆G = ∆H – T∆S.E. Only processes with a negative ∆G are spontaneous..e.g. some chemical reactions.F. Spontaneous processes can be harnessed to perform work.G. Free energy is a measure of a system’s instability, its tendency to change to a more stable state.H. During a spontaneous change, free energy decreases and the stability of a system increases.I. Equilibrium is a state of maximum stability.J. A process is spontaneous and can perform work only when it is moving toward equilibrium.K. Free energy is relative:a) Position relative to gravityb) Concentration gradient (amounts on 2 sides of a membrane)c) Relative stability of chemical bonds in reactants and productsVII. Units of EnergyA. The unit of energy is the “calorie”B. 1 calorie = the amount of energy needed to raise 1 gram of H2O 1oCC. 1 dietetic Calorie = 1000 caloriesD. 1 oz bag of potato chips has 150 CaloriesE. 150 Calories = 150,000 caloriesF. This amount of energy would heat 1500 g of water (1.5L) from 0 to 100oC…i.e. would boil water. That’s a lot of energy!VIII. Order as a characteristic of lifeA. Cells create ordered structures from less ordered materialsB. Organisms also replace ordered forms of matter and energy with less ordered forms..e.g.cows eat grass and metabolize it to water and CO2C. On a larger scale, Energy flows into an ecosystem in the form of light (which is used by photosynthesis) and exits in the form of