BIOL 120 1st Edition Lecture 8 Outline of Last Lecture I Lipids continued II Lipids structure a phospholipids glycerol phospholipids amphipathic III Proteins key concepts IV Structure a peptide bond polypeptide N terminus C Terminus V Protein functions Outline of Current Lecture I Protein Structure a denatured renatured II Catalyst and Enzymes a catalyst activation energy enzymes III Cell Structure Intro a cell theory resolution IV Prokaryotic cells beginning a Plasmids Current Lecture I Protein Structure hierarchy 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 1 Primary A unique sequence of amino acids B Polypeptide properties and function are affected by R group amino acids C Single amino acid change affects and alters protein function 2 Secondary A Folding of primary structure hydrogen bonds connect the COOgroup of one amino acid with the NH3 group of another B Can bend into either i Alpha helices ii Beta pleated sheets 3 Tertiary A the interaction between R groups or between R groups and the peptide backbone bonding secondary structures together i bonded through hydrogen bonds hydrophobic interactions van der Waals interactions covalent disulfide bonds two amino acids have this sulfer and ionic bonds 4 Quaternary A the combination of distinct polypeptide subunits that interact to form a single structure 5 Folding and Function A denatured unfolded protein is unable to function normally Quaternary primary B Renaturation normal folding primary Quaternary C Molecular chaperones help proteins in cells fold correctly in order to function II Catalyst and Enzymes 1 Catalyst a substance that lowers the activation energy of a reaction and increases the rate of reaction A Catalysis is the most fundamental protein function B lowers the activation energy of a reaction by lowering the free energy of the transition state cannot change G and is not consumed C Activation energy the amount of free energy required to reach the intermediate condition or transition state i Reaction rate depends on 1 kinetic energy of the reactants 2 concentration of the reactants 3 G 4 activation energy of the particular reaction 2 Enzymes protein catalyst that typically catalyze only one reaction A they bring reactants together in a precise orientation B they stabilize transition states C They work by bringing together substrates into a specific position this stabilizes the transition state and lower the activation energy needed D Steps of enzyme catalysis 1 Initiation 2 Transition state facilitation 3 Termination III Cell Structure 1 Cell Theory All organisms are composed of cells cells are the basic unit of life cells arise only from pre existing cells 2 Size is limited by A surface area available B Temperature C Concentration gradient D Distance 3 Microscopes A most cells are not visible to the naked eye B Resolution minimum distance two points can be apart and still be distinguished as two separate points C Can use either light microscope or Electron microscope 4 Grouping cells A Prokaryotes lack a membrane bound nucleus i Bacteria and Archaeal B Eukaryotes have a membrane bound nucleus and membrane bound organelles i Eukarya IV Prokaryotic Cells 1 Structure A All lack a membrane B Bacteria a lack a membrane bound nucleus b Has a plasma membrane c Posses a single chromosome nucleoid i contains a long strand of DNA and a few supportive proteins d Has ribosomes which synthesize proteins e Stiff cell wall f Some contain plasmids small supercoiled circular DNA molecules 2 Genetic information A most prokaryotic cells have one supercoiled circular chromosome found in the nucleoid DNA