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Unformatted text preview: Biochem 2EE3 Exam Study Sheet Lecture 1: Origin of Life Microfossil of bacteria dates back to 3.5 billion years ago Earth formation occurred 4.6 billion years ago earliest fossil organisms 3.5 billion years ago prebiotic era 1.1 billion years ago Miller and Urey Experiment: CH4 + NH3 + H2O + H2 Gly, Ala, Glu, Asp + other simple compounds Stromatolites contain layers of sediment intermixed with different microbe types Body Composition Dry Weight C= 61.7%, N=11%, O=9.3% The body is composed of 70% water, so the most abundant molecule by weight is oxygen Major Ionic Compounds of seawater and extracellular fluid include Na, Mg, Ca, K, Cl Cl is most present followed by Na in seawater, while in extracellular fluid its Na followed by Cl Simple molecules combine end-to-end to form polymers (condensation or hydrolysis) Prokaryotes simple structures, unicellular, most numerous organism on earth, 1-10 micrometres in length, and do not have intracellular membranes Multicellular organisms arouse about 700-900 million years ago Mitochondria may have evolved from a free-living bacteria that formed relationships with eukaryote E. Coli inhabits the mammalian colon and contains millions of molecules representing 3000-6000 different compounds Eukaryotes an animal may contain 100 000 different types of molecules, 10-100 micrometres long, have nucleus and skeleton, have membrane-enclosed organelles Lecture 2: Energy, Entropy, and Molecular Interactions Spontaneous Process occurs without the input of energy The normal activities of living organisms demand a constant input of energy Thermodynamics studies relationships between heat and other forms of energy In thermodynamics, a system is part of the universe, the rest of the universe is called the surroundings 1 st Law of Thermodynamics the total amount of energy in the universe is constant, although the form of energy may change Entropy (S) indicates the degree of randomness of a system (Boltzmann Constant S=k B ln W) 2 nd Law of Thermodynamics spontaneous processes are characterized by an increase in the entropy of the universe For a spontaneous process under constant T ΔS≥ΔH/T The energy of a system (U) is the difference between the heat (Q) exchanged with the surroundings and the work (W) done by the system on the surroundings: U=Q-W Q =U+W Exergonic Process: G <0 Endergonic Process: G>0 Free Energy: G=H-TS Hydrogen Bonds can occur within a molecule and between molecules (influence protein folding) Bond Strength From Strongest to Weakest: Covalent, Ionic, Hydrogen Bond, Dipole, Van der Waals Noncovalent Bonds: stabilize 3D structure of proteins and other biopolymers Water accounts for about 70% of the body weight and each molecule is bonded to 3.4 neighbours Hydrophobic effect is the tendency of water to minimize its contacts with nonpolar molecules...
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This note was uploaded on 10/11/2010 for the course ECONOMICS ECON 1B03 taught by Professor Holmes during the Fall '08 term at McMaster University.
- Fall '08