BMB 401 Exam I FS 9 18 2014 3PM Eastern Time Form A LOGARITHMS THAT MIGHT BE USEFUL log 7 log 8 log 9 log 10 log 100 ANTILOGS THAT MAY BE USEFUL 0 84 0 90 0 95 1 0 2 0 anti log 1 10 anti log 2 100 anti log 3 1000 anti log 1 1 10 anti log 2 1 100 anti log 3 1 1000 pKas of Amino Acid Functional Groups Amino Acid 1 and 3 letter Codes A C D E F G H I K L Ala Cys Asp Glu Phe Gly His Ile Lys Leu Alanine Cysteine Aspartate Glutamate Phenylalanine Glycine Histidine Isoleucine Lysine Leucine M N P Q R S T V W Y Met Asn Pro Gln Arg Ser Thr Val Trp Tyr Methionine Asparagine Proline Glutamine Arginine Serine Threonine Valine Tryptophan Tyrosine Unit Conversion nM 10 9 molar M 10 6 molar mM 10 3 molar 1 BMB 401 Exam I FS 9 18 2014 3PM Eastern Time Form A 2 1 Please select the true statement a Ionic bonds are directional b The fatty acid tails of membrane lipids primarily associate through van der Waals interactions c In solving for the energy present in an ionic bond positive values of E are attractive whereas negative values for E are repulsive d All the statements above are true 2 Which buffer is optimal for an enzymatic reaction if the enzyme optimal pH 5 8 Note this reaction releases CO 2 a Acid A with the following pKas pKa1 3 2 pKa2 4 8 pKa3 9 2 b Acid B with the following pKas pKa1 4 1 pKa2 9 8 c Acid C with the following pKas pKa1 6 1 pKa2 7 8 d Acid D with the following pKas pKa1 2 0 pKa2 4 7 pKa3 8 1 3 Please select the true statement a RNA is used as the template during replication b DNA is used as a template during the transcription of proteins c The polymerization of RNA requires ATP for energy to power the synthetic reaction d In bacteria like E coli splicing of mRNA does not occur 4 Which of the following is true a Carbon dioxide produced in metabolically active cells is used to make carbonic acid in red blood cells b The heme ring is an asymmetrical prosthetic group as the portion that is buried in the globin chain and the portion that contacts the aqueous solution are not the same c Hemoglobin in the tense state has a lower affinity for oxygen than hemoglobin in the relaxed state d All the above are true e Only a and c are true 5 The chloride shift promotes the movement of bicarbonate into red blood cells in the capillaries surrounding metabolically active tissues by pumping Cl ions out of red blood cells here True False 6 What is the pH of a liter of 10 mM NaOH a 13 8 b 12 c Approximately 7 d 2 e 1 8 f The correct pH is not shown here 7 Please select the true statement a Fetal hemoglobin is a tetramer of two alpha globin chains and two beta globin chains b Myoglobin is primarily alpha helix in secondary structure and shares the tertiary and quaternary structure of hemoglobin c Myoglobin and the globin chains of hemoglobin are homologs d Myoglobin functions as a tetramer and shows allosteric binding kinetics e All but a are true 8 Please choose the true statement a Buffers are weak acids that buffer most effectively at the pKa of the acid but can buffer within one pH unit above and one pH unit below the acid s pKa b At a pH greater than the pKa of an acid the acid is present at higher concentration than its conjugate base c The bicarbonate buffer system is the primary cellular buffering system d Free amino acids can function as buffers e All the above are true f Only a c and d are true g Only a and d are true BMB 401 Exam I FS 9 18 2014 3PM Eastern Time Form A 3 9 Please select the true statement a The proximal histidine of hemoglobin acts to limit access to the central iron ion and prevent superoxide release b When oxygen leaves the hemoglobin oxygen binding site as superoxide the resultant oxidation state of that iron ion in the heme molecule is 3 c The primary function of myoglobin is to carry oxygen in the blood d All of the above are true 10 In adding amino acids to form a peptide a peptide bond forms between the alpha amino group of the amino acid already in the chain and the alpha carboxy group of the incoming amino acid being added True False 11 In the lipid bilayer lipids are held together by covalent bonds to form the lipid membrane True False 12 In aqueous solution polar amino acids are most commonly on the outside of a protein while non polar amino acids are generally buried inside the protein away from the aqueous solution True False 13 Please select the FALSE answer a The four elements at the highest mole percent in humans are H C N O b Amino acids in living organisms are in the L configuration c A covalent bond between two carbon atoms has a higher bond energy than the van der Waals interactions between two carbon atoms d Hydrogen bonds are non directional interactions 14 Please select the true statement a Prolines tend to kink the peptide backbone and are commonly found in areas where the peptide backbone changes direction such as the beginning of an alpha helix b Free alanine has a positive charge of one in aqueous solution at physiologic pH c Glycine is one of the most commonly substituted amino aids in proteins because it is so small d Disulfide bonds form between two cysteine residues under reducing conditions e All the above are true except b f Only a and d are true 15 Select the FALSE statement a Alpha helices are held in position by hydrogen bonds parallel to the axis of the helix b Hydrogen bonds that stabilize alpha helices form between main chain atoms 3 4 amino acids apart c Peptide bonds show partial double bond characteristics d Beta strands are held together by hydrogen bonds between R groups e Amino acid R groups project outward from the alpha helices 16 Alpha helices are right handed helical structures that are hollow at the center of the helix True False Figure 1 17 The structure in Figure 1 is a Lipid b DNA c Protein d RNA 18 The amino acid sequence of a yeast protein is 80 identical to its human homolog but the DNA sequences of the genes that encode these two proteins are only 65 identical How can this be a Changes in amino acid sequence are tolerated more easily than changes in DNA sequence b Changes in amino acid sequence rarely result in loss of function while changes in DNA coding sequence generally does result in a change in the function of the …
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