NAME Network ID SECTION TA MCB 150 Practice Exam 1 Choose the BEST answer from the choices given and mark it on your answer sheet Each question is worth three 3 points with the exception of question 34 worth 1 point 1 Which of the following functions is least likely to be occurring in the nucleus A Production of RNA from information in DNA B Maintenance and replication of the genome C Sorting and distribution of secreted proteins D Synthesis and assembly of ribosomal subunits E All of the above functions are equally likely to be occurring in the nucleus BL 2 DL 1 LO 3 1 2 True or False The phospholipids in the bilayer surrounding each ribosome are composed of specialized head groups that allow for facilitated transport of amino acids into that ribosome s active site A True B False BL 3 DL 2 LO 3 1 5 2 3 There are species of bacteria or archaea known to grow A B at temperatures of 0 C under Antarctic ice C D All of the above E None of the above at a pH lower than 1 0 in water that is 5 10 times saltier than seawater BL 1 DL 1 LO Readings 1 4 Which of the following chemical formulas would represent an oligosaccharide of six hexose sugars A C36H72O36 B C30H60O30 C C36H62O31 D C30H50O25 E C36H60O30 BL 3 DL 1 LO 4 2 The following figure represents four amino acids labeled W X Y and Z The amino terminus of each amino acid is on the left of the figure and the carboxy terminus of each amino acid is on the right of the figure labeled as shown below Use the figure to answer the next three 3 questions 5 Assume amino acids W and X are hydrophobic Y is proline and Z is acidic How many possible combinations are there for peptides in the order W X Y Z A B C D E 40 100 200 4 000 160 000 BL 4 DL 2 LO 5 1 2 6 If the sequence of a peptide is Y X Z W from amino to carboxy terminus peptide bonds would be found between A R O P S T N B Q O P T S M C R P O S T N D Q P O T S N E R O P S T M True or False If the peptide sequence W X Y Z was part of a larger polypeptide and W and Z were both cysteines tertiary structure could be stabilized by a linkage between N and T A True B False BL 4 DL 3 LO 5 2 7 BL 3 DL 2 LO 5 3 3 8 A planar phospholipid bilayer was formed across a small hole in a partition that separates two aqueous compartments as shown in the figure below A mixture of two molecules A and B was added to one of the compartments and the fate of both molecules was followed over time 120 minutes later molecule A was evenly distributed between the two aqueous compartments while the distribution of molecule B was unchanged What is the most likely identity of molecules A and B A Molecule A is nitrogen N2 molecule B is oxygen O2 B Molecule A is potassium K molecule B is glycerol C Molecule A is water H2O molecule B is sodium Na D Molecule A is glucose molecule B is carbon dioxide CO2 E None of the above identities are likely for molecules A and B BL 5 DL 1 LO 8 1 4 9 Listed below are biological molecules and the building blocks from which they are made Amino Acids i Fatty Acids ii iii Monosaccharides iv Nucleotides a Lipids b Carbohydrates c Nucleic Acids d Proteins Match the monomer on the left with the most appropriate macromolecule on the right A B C D E i c ii a iii b iv d i d ii a iii b iv c i c ii b iii a iv d i d ii c iii a iv b i d ii b iii a iv c BL 1 DL 1 LO 3 2 10 Which of the following statements about enzyme inhibition is correct Irreversible inhibitors are typically molecules that are synthesized by the cells in A which the inhibition is observed B A competitive inhibitor indirectly prevents the binding of the natural substrate to the enzyme C A non competitive inhibitor must physically resemble the natural substrate in order to effectively inhibit the enzyme In irreversible enzyme inhibition if the concentration of inhibitor molecules is greater D than the concentration of enzyme the effects of the inhibitor can be overcome by increasing the concentration of natural substrate E None of the statements about enzyme inhibition are correct BL 2 DL 2 LO 6 4 5 The figure below represents two nucleotides at the end of a long nucleic acid chain Use the figure to answer the next two 2 questions C A D E B 11 Without needing to know the specifics of the structures of the nitrogenous bases you could conclude that the base nearest the region labeled C is most likely to be guanine A B thymine C adenine D uracil E With only the information provided in the figure it is not possible to differentiate among the four options shown above BL 4 DL 2 LO 7 1 7 2 12 BL 2 DL 1 LO 7 2 If another monomer was to be added to this chain it would be covalently linked to the region of the molecule shown labeled A B C D E A B C D E 6 13 Which one of the following structures would least likely be found in a molecule of phosphatidyl serine A C E B D BL 4 DL 2 LO 7 4 8 1 14 Which pyrimidine base s is are found in DNA but not RNA A Thymine B Uracil C Cytosine D E A and C A B and C BL 2 DL 1 LO 7 1 7 Use the following figure to answer the next three 3 questions The figure represents a typical activation energy diagram for a reaction in which substrate S is converted into product P The solid curve indicates the conversion of S into P in the absence of enzyme and the dotted curve indicates the conversion of S into P in the presence of enzyme 15 Which point on the Y axis represents the energy level of the product s of this reaction BL 2 DL 1 LO 6 2 6 3 16 The change in free energy of the uncatalyzed reaction is represented by the distance on the A B C D A B C D Y axis between A B and C B A and C C and D C D A and B E B and D BL 2 DL 2 LO 6 2 6 3 8 17 Which one of the following metabolic reactions would most likely be represented by the figure shown A Elongation of a cellulose fibril by attaching …