2022年清华大学XX生物化学1本科期末考试试题.docx

精品学习资源清华高校 XX年生物化学 1 本科期末考试试题考试科目：生物化学考试时间：考试类型：期末试题I.1: how many carbons does Arachidic acid have. 20 carbons2: how many double bonds does Arachidonic acid have. 4 double bonds3: list two advantages that fats have over sugars as stored fuels more energy gram for gram; no hydration needed4: where inside the cells are most of the phospholipids degraded lysosomes5: oligosaccharide head groups determine the blood type of an individual. How are they attached to the plasma membrane. glycosphingolipids or lipids and surface proteins6:listatleastonegeneticdiseasethatcouldresultfromabnormalaccumulation of membrane lipids Tay-Sachs, Sandhoffa.s, Fabrya.s, Gauchera.s, orNiemann-Pick diseases7: list the three main eicosanoids that produced from arachidonic acid prostaglandins; thromboxanes; and leukotrienes.8:listone NASID youknow aspirin,ibuprofen,oracetaminophenor meclofenamate 9: list two fat-soluble vitamins A, D, E, K10: which vitamin can be derived from beta-carotene A.11: which year was the fluid mosaic model proposed. 197212: why the thickness of most biological membranes is thicker than 3nm, the standard thickness of lipid bilayer. due to association of proteins to the membrane and carbohydrates on the membrane13:Pleasedefinethetransitiontemperatureofthelipidbilayerthetemperature above which the paracrystalline solid changes to fluid14: If a membrane protein has its N-terminus exposed to the outside of the cellwhile its C-terminus resides in the cytosolic compartment, is it a type I transmembrane protein . yes.15: How can you predict if a protein has a transmembrane domain. hydropathy orhydropathy index, or hydropathy plot.16: Name the two cell surface receptors that HIV use to enter cells CCR5 and CD4.17: For the Na+ K+ ATPase, how many Na+ and K+ can it move across the membrane for the hydrolysis of one ATP 2 K+ in, 3 Na+ out.18: what drives F-type ATPases to synthesize ATP. proton or proton gradients 19: The acetylcholine receptor is a-gated channel Ligand20: The neuronal Na+ channel is a-gated channel voltage II.欢迎下载精品学习资源D and H3 points The antiparallel orientation of complementary strands in duplex DNAwas elegantlydeterminedin1960by ArthurKornbergby nearest-neighboranalysis.In this technique, DNA is synthesized by DNA polymerase I from onealpha-32P-labelled and three unlabelled deoxynucleoside triphosphates. Theresultingproductisthenhydrolyzedby a Dnasethatcleavesphosphodiesterbonds on the 3a. sides of all deoxynucleotides. For example, in the labeled dATPreaction,ppp*A + pppC + pppG +pppT -. a.|pCpTp*ApCpCp*ApGp*Ap*ApTpa.|- . a.|+Cp+Tp*+Ap+Cp+Cp*+Ap+Gp*+Ap*+Ap+TpTa.|If in the dATP labeled reaction the relative radioactivity of Tp*, Gp*, Cp* and Ap* is 0.2, 0.3, 0.4 and 0.1.In the labeled dGTP reaction, Tp* radioactivity will be A 0.1B 0.2C 0.3D 0.4E 0In the labeled dCTP reaction, Tp* radioactivity will be F 0.1G 0.2H 0.3I 0.4J 0 B1 point A molecule of amylopectin consists of 1000 glucose residues and is branched every 25 residues. How many reducing ends does it have.A) 0B) 1C) 25D) 40E) 41F 10001 point DA mirror image of B form DNA isA) Z-DNAB) A-DNAC) B-DNAD) does not exist in nature 1 point AWhich of the following statements is not true.A) all natural occurring DNA is in B formB) A-DNA probably does not exist in vivoC) Both major groove and minor grove of B-DNA are deep欢迎下载精品学习资源D) B-DNA is right handed, while Z-DNA is left handed. 1 point ALung fish has 100,000,000 kb kb=1000 base pairs for its haploid genome. The total length of this DNA isA) 34 mB) 3.4 mC) 1 mD) 17 mE) 1.7 mF) 34 mm3 points. 1.5 point A, D, EBoth tubes X and Y contain the same DNA in 0.1 M NaCl solution. In tube X moreNaClisaddedandintubeY some ethanolisadded.Whichofthefollowingisare correct.A) tube X will have higher Tm than YB) tube Y will higher Tm than XC) tube X and Y will have the same TmD) tube X will have higher Tm than originalE) tube Y will have lower Tm than original 1 point DWhich of the following is NOT correct.A) Glycosaminoglycan chains are linearB) Glycosaminoglycan chains are acidicC) Glycosaminoglycans are composed of repeating disaccharide unitsD) Different glycosaminoglycans have the same disaccharide units 1 point CThe so-called table sugar or cane sugar is a disaccharide ofA) galactose and glucoseB) 2 glucose unitsC) glucose and fructoseD) galactose and fructose 1 point ALactose is a disaccharide ofA) galactose and glucoseB) 2 glucose unitsC) glucose and fructoseD) galactose and fructose 1 point BChoose the INCORRECT statement. In dideoxy sequencing or Sangera.s method,A) the newly synthesized DNA is labeled while the template is notB) the template has to be labeledC) a primer has to be usedD) ddNTPs are used to terminate elongation 1 point B学习文档 仅供参考欢迎下载精品学习资源ChoosetheINCORRECT statement.InMaxam-Gilbertsequencingorchemicalmethod,A) the template is labeledB) a primer is neededC) enzyme is not neededD) nucleotide analogues are not used 1 point Duv radiation in the solar light directly cause which kind of the following DNAdamage.A) deaminationB) methylationC) DNA breakageD) pyrimidine dimer formationE) depurination 1 point CRNA is sensitive to alkaline hydrolysis becauseA) RNA has uridine instead of thymidine in its sequenceB) RNA has hydroxyl group at 4th and 5th positions of its riboseC) RNA has hydroxyl group at 2nd and 3rd positions of its riboseD) RNA is mostly single strandedE) RNA forms three dimensional structure 1 point DWhich of the following is NOT a carbohydrateA) glucoseB) maltoseC) glycogenD) proteglycanE) glycosaminoglycan3 points.1.5 point C, E, FWhich of the following is are NOT branchedA) glycogenB) starchC) celluloseD) amylopectinE) amyloseF) chitin1 point AShown on the right isA) AB) GC) TD) CE) U1 point CShown on the right is欢迎下载精品学习资源A) AB) GC) TD) CE) U III.1) The followsaretheimportantfeaturesofsignaltransductionsystemsEXCEPT :A. AmplificationB. Desensitization/turn-offC. SpecificityD. SimplicityE. Integration2) Relative to the outside of a cell, calcium concentration inside the cell is:A. HigherB. LowerC. Approximately equal3) Hydrolysis of GTP to GDP is essential for the normal function of all the GTP-binding proteinsA. TrueB. False4) cAMP-dept kinase PKA regulates only sugar metabolismA. TrueB. False5) The follows are among the intracellular second messengers EXCEPT:A. cAMPB. cGMPC. Ca2+D. IP3E. ATP6) How does IP3 work as a second messenger. A. . By activating phaspholipase CB. . By activating protein kinase CC. By activating Ca2+ channelsD. By activating G.±S7) The insulinreceptorhastyrosinekinaseactivitywhichphsophorylatesseveral different proteins including itselfA. TrueB. False8) The insulin signal is amplified via the MAP kinase cascadeA. TrueB. False9) All signaling pathways are very unique and very specific, and they dona.t talk to each otherA. True学习文档 仅供参考欢迎下载精品学习资源B. False10) Which of the followings is UNIQUE to TGFA. transmembrane proteinsB. Ser/The receptor kinasesC. Ligand binding activity present in the extracellular domainD. Become activated upon ligand binding2 .receptors.欢迎下载精品学习资源11) The activity of CDK proteins is tightly regulated by the following events EXCEPT :A. PhosphorylationB. DephosphorylationC. Cyclin bindingD. UbiquitinationE. CDK inhibitors12) Caspases play essential roles in apoptosis. The following are among their effects EXCEPT:A. Activation of DNaseB. Activation of other caspasesC. Inducing cell shrinkageD. Stimulating gene expression13) Cancer can be a result of the following events EXCEPTA. Activation of mitogenic signalsB. Cell cycle arrestC. Inactivation of negative regulators for cell growthD. Blockage of cell apoptosis14) In 2002, the Nobel Price for Physiology or Medicine was awarded for the research onA. PhosphorylationB. Cell cycleC. ApoptosisD. G proteinE. OncogenesAnswers for Biosignaling:1) D2) A3) A4) B5) E6) C7) A8) A9) B10) B11) D12) D欢迎下载精品学习资源13) B14) C IV.1. Whichofthefollowingstatementabout2,3-bisphosphoglycerateBPGiswrong: d(a) BPG binds at a site distant from the oxygen-binding site of hemoglobin.(b) BPG regulates the oxygen-binding affinity of hemoglobin in relation to the pO2 in the lungs.(c) BPG concentration in normal human blood at sea level is lower than that at high altitudes.(d) BPG greatly increases the affinity of hemoglobin for oxygen.2. Antibodies of the IgG class : d(a) consist of four subunits.(b) have noncovalent bonds and disulfide crosslinks.(c) are abundant in the blood.(d) All three choices are correct.3. ELISA allows for rapid screening and quantification of the presense of an antigen in a sample. Which of the following steps of ELISA is wrong: a(a) Proteins in a sample are adsorbed to an inert surface, and the surface is washed with a solution of specific protein similar to the protein of interest,to block proteins in subsequence steps from also adsorbing to these surfaces.(b) The sample was treated with a solution containing antibodies against the protein of interest. Unbound antibody is washed away, and the sample is treated with with a solution containing antibodies against the primary antibody.(c) These secondary antibodies have been linked to an enzyme that catalyzes areaction that forms a colored product.(d) After unbound secondary antibody is washed away, the substrate of theantibody-linkedenzymeisaddedandtheproductformationisproportionaltothe concentration of the protein of interest in the sample.4. The major proteins of muscle are: c(a) Myosin and hemoglobin(b) Actin and troponin(c) Myosin and actin(d) Myoglobin and actin5. Positive cooperative binding can be identified by c(a) a hyperbolic binding curve.(b) a Hill plot with a slope less than one.(c) a Hill plot with a slope greater than one.(d) Choices a and b are both correct.6. Which pair of amino acids absorbs the most UV light at 280 nm. b(a) Thr & His.(b) Trp & Tyr.(c) Phe & Pro.(d) Phe & Pro.学习文档 仅供参考欢迎下载精品学习资源7. The strong conclusion from Anfinsen's work on RNaseA was that: b(a) 100% enzyme activity corresponds to the native conformation.(b) the sequence of a protein determines its structure.(c) Cys-SH groups are not found in vivo.(d) disulfide bonds S-S in proteins can be reduced in vitro.(e) irreversible denaturation of proteins violates the "Thermodynamic Hypothesis".8. Which of the following statement about protein folding is wrong: c(a) Some proteins undergo assisted folding by chaperons.(b) Polypeptides fold rapidly by a stepwise process.(c) Misfolding may cause misfunctioning, but does not cause death.(d) A lossof3-dproteinstructuresufficienttocauselossoffunctioniscalled denaturation.9. Hydrogen bonds in a-helices are d(a) more numerous than Van der Waals interactions.(b) not present at Phe residues.(c) analogous to the steps in a spiral staircase.(d) roughly parallel to the helix axis.(e) about 5. in length.10. What is the appoximate molecular weight of a protein with 200 amino acid residues in a single polypeptide chain: ba 11000b 22000c 44000d 66000 V.1. What are the two most striking characteristics of enzymes. 1 pt, 0.5 pt x2Answer:The two most striking characteristics of enzymes are their 1 catalytic power,2 specificity.2. . How does an enzyme gain its catalytic power. 2 pt, 1 pt x 2 Answer:1) Enzymes bring substrates together in an optimal orientation;2) They catalyze reactions by stabilizing transition states;3.Isthestructureofthebindingsiteofan enzymecomplementarytoitssubstrate or to transition state. Why. 1 pt, 0.5 pt x 2Answer: An enzyme is in complementary in structure to the transition state of the substrate because the activation barrier is lowered during such a binding.4. . How many general ways of regulations on enzyme Activity. 2 pts, 0.5 pt x 4Answer:1) Feed-back Inhibition2) Regulatory Proteins欢迎下载精品学习资源3) Covalent Modification4) Proteolytic Activation5. List the common features of enzymes 2.5 pts, 0.5 pt x 5 Answer:1) The active site take up small volume compare with the entire protein volume;2) The active sites are composed of amino acid residues located in different positions on a linear sequence;3) An enzyme binds to its substrate via multiple weak interactions;4) Active sites are clefts or crevices;5) The specificityofbindingdependsonpreciselydefinedarrangementofatoms in an active site.6. How many types of weak interactions involved in the binding of a substrateby an enzyme. 2 pts, 0.5 x 4 Answer:1 Electrostatic interactions; 2 Hydrogen bonds; 3 van der Waals forces; 4Hydrophobic interactions.7. WritedowntheMichaelis-Mentenequation0.5pt,whatisthemeaningofKm. 0.5 ptUnderwhichconditiontheKm isa measureoftheaffinityoftheenzyme for the substrate. 1 pt, what is the meaning of Vmax. 0.5 pt What is thephysical limit of the value of k3/km. 1 pt Answer:Michaelis-Menten equation: V = Vmax S/S + KmKm is equal to the substrate concentration at which the reaction rate is half its maximal rate value.Km is a measure of the enzymea.s affinity only when K2 >> K3 i.e., thedissociationrateconstantofES ismuch greaterthanthecatalyticrateconstantVmax is reached when all the catalytic sites on an enzyme are saturated with substrate.The physical limit of the value of k3/km is that the enzyme-catalyzed reaction rate is rate of diffusion of both the substrate and the enzyme.VI.The following statements are true T or false F.1. The biological system is an open system; living organisms are at equilibrium with their surroundings. 1.5False:The biologicalsystemisindeedan opensystem,abletoabsorbandexchangematerialswith theenvironment.Howeverthelivingorganismsuseenergyto,for example, keep their own concentrations of ions inside the cells, which are notnecessarily of the same concentrations in the environment.2. Activationenergyfora chemicalreactionistheenergyrequiredfora chemical reaction to convert the reactant to transition state, but does not measure thefree energy change between the reactants and products.