Biosc 0150 Foundations of Biology I Review Chapter 3 4 5 6 1 Origin of Life Review Chapter 3 Proteins a What were the two key compounds in chemical evolution that were required for reactions that lead to the synthesis of more complex organic molecules Hint These two molecules were discovered to be the key to chemical evolution in Stanley Miller s Spark Discharge Experiment Formaldehyde H2CO and hydrogen cyanide HCN b Miller s experiment simulated the second stage in chemical evolution the formation of a soup Prebiotic c In early Miller s simulations of early Earth the molecules did not undergo spontaneous chemical reactions even at high temperatures no matter how much he boiled the ocean water What aspect did he need to add to his experiment for it to be successful in making the two key molecules in chemical evolution What did this element represent in early Earth s conditions Electrical discharges added pulses of intense electrical energy sparking was key in tandem with the boiling of the water It represented lightning in early earth Formation of H2CO and HCN are endergonic reactions 2 Amino Acid Structure a Carbon atoms have a valence of Four b What are the four groups parts making up an amino acid Amino functional group carboxyl functional group hydrogen atom and R group side chain c Which of the four groups affects reactivity of different amino acids the most Why R group it is the only fourth of the amino acid that varies between amino acids d How would a hydrocarbon R group on an amino acid affect its solubility in water It would cause the amino acid to be much less soluble or not soluble at all in water e What type of side chain charged uncharged would interact with water the best This would make the amino acid dissolve in water more easily rarely Charged more easily 3 Polymerization of Amino Acids into Proteins a Do amino acids polymerize spontaneously Why or why not No entropy is decreasing increasing entropy is spontaneous polymers are also much less stable than monomers early earth conditions were energy rich environments to overcome this b Monomers polymerize via dehydration hydrolysis reactions This is named so because the newly formed bond results in the loss of Dehydration a water molecule c When a bond forms between the group of one amino acid and the group of another a C N bond is formed in a condensation reaction This is also known as a bond Why are these bonds unusually stable Carboxyl group amino group peptide the electrons involved are partially shared between the new peptide bond and the neighboring carbonyl functional group they have characteristics of a double bond making the bond planar 4 Explain why the lock and key model of an enzyme proposed by Emil Fischer is not fully true Fischer s lock and key model said that substrates enter the active site of enzymes and that the enyzme s shape remains static in the process This is not true When enzymes encounter their specific substrates they make conformational changes known as induced fits which help bring substrate molecules together so that they can undergo the fastest possible reactions Adel Anthony Kathleen Megan Dr Swigonova Page 1 of 20 Biosc 0150 Foundations of Biology I Review Chapter 3 4 5 6 5 As a group proteins perform more types of cell functions than any other type of molecule does Fill in the blanks considering proteins versatility a A protein that functions as a catalyst is called a an Enzyme b When you get sick certain proteins called come to attack and destroy the virus Antibodies c Actin and myosin are referred to as proteins Their main function is Motor to move the cell itself or to move large molecules inside the cell d Hemoglobin is a protein is Transport to transport oxygen from the lungs to the rest of the body function Its 6 Discussion about Enzymes a Enzymes are extremely important to living organisms In one or two sentences describe what an enzyme is be specific yet precise An enzyme is a protein that acts as a catalyst and lowers the activation energy for chemical processes in cells By lowering activation energy also known as free energy of the transition state the speed of chemical reactions increases immensely allowing life to exist b Question Without enzymes would the biochemical processes that support life be able to occur efficiently and quickly enough so that organisms could remain in existence i Definitely ii Absolutely not iii I m not quite sure iv Yes if the organism drinks enough Red Bull Answer B 7 Given the diagram right answer the following questions a Arrow 1 refers to the of the reaction Activation Energy b Arrow 2 refers to the change in of the reaction also known as G S H Free energy G c Do you expect the addition of an enzyme catalyst to alter the activation energy of the reaction What about the change in free energy of the reaction The addition of a catalyst will lower the activation energy of the reaction letting it proceed faster However a catalyst does not affect the change in free energy of the reaction As you may learn in your chemistry courses activation energy is a kinetic quantity which has to do with the rate of reaction while free energy is a thermodynamic quantity which has to do with the extent of a reaction There is no mathematical relationship between the kinetics and thermodynamics of a reaction therefore catalysts have no effect on thermodynamic quantities d After you ve answered part C decide whether or not a catalyst will make a nonspontaneous reaction become spontaneous Choices yes it will no it will not It will not Adel Anthony Kathleen Megan Dr Swigonova Page 2 of 20 Biosc 0150 Foundations of Biology I Review Chapter 3 4 5 6 8 Answer the following questions on protein folding and functions a An unfolded protein has much higher entropy than a folded protein So why is folding spontaneous The bonds hydrophobic interactions and van der Waals interactions make the folded molecule more stable energetically Folding may release enough free energy to be exergonic and occur spontaneously b What does it mean to denature a protein What are the causes Which structures are affected Denature means unfold Some causes include pH changes presence of alcohols temperature changes and compounds that break hydrogen or disulfide bonds The quaternary tertiary and secondary structures are affected c What is the purpose of molecular chaperons What are prions and why are they so dangerous Molecular chaperons facilitate in the folding of proteins usually after large