1、【简答题】you can answer the question either in chinese or english a 15-year-old african-american female presents to the emergency room with complaints of bilateral thigh and hip pain. the pain has been present for 1 day and is steadily increasing in severity. acetaminophen and ibuprofen have not relieve her symptoms. she denies any recent trauma or excessive exercise. she does report feeling fatigued and has been having burning with urination along with urinating frequently. she reports having similar pain episodes in the past, sometimes requiring hospitalization. on examination, she is afebrile (without fever) and in no acute distress. no one in her family has similar episodes. her conjunctiva and mucosal membranes are slightly pale in coloration. she has nonspecific bilateral anterior thigh pain with no abnormalities appreciated. the remainder of her examination is completely normal. her white blood cell count is elevated at 17,000/mm3, and her hemoglobin (hb) level is decreased at 7.1g/dl. the urinalysis demonstrated an abnormal number of numerous bacteria. 1. what is the most likely diagnosis? 2. what is the molecular genetics behind this disorder? 3. what is the pathophysiologic mechanism of her symptoms?
1、【多选题】3.a 6-year-old african american girl with speech delay is found to have a large, abnormal peak when blood amino acids are measured. the abnormal amino acid migrates toward the cathode, indicating a positively charged side group in addition to its carboxyl and amino groups. which of the following amino acids is most probable? a、alanine b、glycine c、histidine d、leucine e、valine
2、【多选题】select the one of the following statements that is not correct : a、protein folding is assisted by intervention of specialized auxiliary proteins called chaperone. b、protein folding tends to be modular, with areas of local secondary structure forming first, then coalescing into a molten globule. c、protein folding is driven first and foremost by the thermodynamics of the water molecules surrounding the nascent polypeptide. d、the formation of s-s bond in a mature protein is facilitated by the enzyme protein disulfide isomerase. e、only a few unusual proteins, such as collagen, require posttranslational processing by partial proteolysis to attain their mature conformation.
3、【多选题】when using biuret's test, which macromolecule will produce a positive reaction (colour change from blue to lilac)? a、protein b、fat c、carbohydrate d、amino acid e、all four
4、【多选题】which of the following amino acids are belonged to the acidic amino acids? a、phe tyr b、met cys c、leu ile d、glu asp e、gly ala
5、【多选题】1. a 55-year-old british teacher presents with weight loss, weakness, muscle atrophy, and declining cognitive function. her history reveals that her favorite meal is soup made with cow brain, which she has eaten almost every week since she was 10 years old. she is suspected to suffer from bovine spongiform encephalopathy (bse). in comparing viruses with prions, which of the following is most likely? a、both prions and viruses contain some form and quantity of nucleic acid, either dna, rna, or both. b、both viruses and prions upon infection induce an antibody response in the host. c、both viruses and prions upon infection induce an inflammatory response in the host. d、conventional viruses are rapidly inactivated by ultraviolet light or heat, whereas prions are not. e、both viral and prion proteins
6、【多选题】2. the oxygen carrier of muscle is the globular protein myoglobin. which of the following amino acids is highly likely to be localized within the interior of the molecule? a、arginine b、aspartic acid c、glutamic acid d、valine e、lysine
7、【多选题】which of the following amino acids are belonged to the basic amino acids? a、phe tyr b、met cys c、leu ile d、glu asp e、arg lys
8、【多选题】the covalent bond formed between the carboxyl group of one amino acid and the amino group of another amino acid is called______. a、phosphoester bond b、phosphodiester bond c、peptide bond d、glycosidic bond e、thioester bond
9、【多选题】select the one of the following statements that is not correct : a、changes in configuration involve the rupture of covalent bonds. b、changes in configuration involve the rotation of one or more single bonds. c、the ramachandran plot illustrates the degree to which steric hindrance limits the permissible angles of the single bonds in the backbone of a peptide or protein. d、formation of an α-helix is stabilized by the hydrogen bonds between each peptide bond carboxyl oxygen and the n-h group of the next peptide bond. e、in a β-sheet the r-group of adjacent residues point in opposite directions relative to the plane of the sheet.
10、【多选题】proteins are large biological molecules consist of which of the following amino acids? a、l-α-amino acids b、d-α-amino acids c、l-β-amino acids d、d-β-amino acids e、l- and d-β-amino acids
11、【多选题】a single polypeptide that assembles with other polypeptides to form a protein complex is best described as which of the following? a、residue b、secondary structure c、motif d、domain e、subunit
12、【多选题】a part of protein sequence that can form a compact three-dimensional structure and often can be independently folded is called ______. a、residue b、secondary structure c、motif d、domain e、subunit
13、【多选题】consider the following structure: this structure is best described as which of the following? a、an amino acid b、a dipeptide c、a tripeptide d、a tetrapeptide e、a pentapeptide
14、【多选题】select the one of the following statements that is not correct : a、ion-exchange chromatograph separates proteins based upon the sign and magnitude of their charge at a given ph. b、two-dimensional gel electrophoresis separates proteins first on the basis of their pi values and second on their charge to mass ratio using sds. c、affinity chromatograph exploits the selectivity of protein-ligand interactions to isolate a specific protein from a complex mixture. d、many recombinant proteins are expressed with an additional domain fused to their n-or c-terminals. one common component of these fusion domains is a ligand binding site designed expressly to facilitate purification by affinity chromatography. e、tandem mass spectrometry can analyze peptides derived from complex protein mixtures without their prior separation.
15、【多选题】how many amino acids are involved in making proteins in humans? a、5 b、20 c、35 d、64
16、【多选题】consider the amino acid shown below. the configuration about which atom will determine whether the amino acid is in the d or l configuration? a、如图 b、如图 c、如图 d、如图
17、【多选题】amino acids join up into a large chain (polymer) to create what biological molecule(s)? a、dna b、proteins c、bone d、fats
18、【多选题】select the one of the following statements that is not correct : a、the bohr effect refers to the release of protons that occurs when oxygen binds to deoxyhemoglobin. b、shortly after birth of the human infant synthesis of the α-chain undergoes rapid induction until it comprises 50% of the hemoglobin tetramer. c、the β-chain in fetal hemoglobin is present throughout gestation. d、thalassemias are genetic defects due to partial or total absence of the α- or β-chains of hemoglobin. e、the taut conformation of hemoglobin is stabilized by several salt bridges that form between the subunits.
19、【多选题】a 56-year-old pathologist was taken to his family doctor by his son for he was showing mood changes, minor loss of memory, and decreased motor skills. during the patient history, it became clear that over the course of his career he had, on occasion, cut himself using the instruments he had been using on the cadavers he had been working on. a potential explanation for his symptoms is abnormal aggregation of which of the following proteins? a、hemoglobin in the red blood cells b、collagen in the extracellular compartment of the brain c、a truncated neuronal protein d、a misfolded form of a normal protein e、a truncated extracellular protein
3.1前置问题及学习目标
1、【简答题】珍奥核酸是一种口服保健品，有用吗？
3.6必交作业
1、【简答题】a 21-year-old female presents to the physician’s office with complaints of very painful vulvar ulcers. the patient states she has had the symptoms for approximately 3 days, and they are worsening. she says that prior to the ulcerations, there was a burning and tingling sensation of the skin in the same area. she has noted similar symptoms like this before and has been told it is sexually transmitted. on examination you see multiple extremely tender, vesicular (blister-like) lesions on an erythematous (red) base on both labia major of the vulva. she has a moderate amount of tender inguinal lymph nodes bilaterally. the physician uses a swab to sample the ulcer and send it off for diagnostic analysis. 1.what is the most likely diagnosis? 2.if the test is for deoxyribonucleic acid (dna), what method would be used to amplify the fragments of dna sampled?
1、【多选题】dna secondary structure is a right-handed double helix with a sugar phosphate backbone on the outside and paired bases (a-t, g-c) on the inside. which of the following are true? a、the two strands are parallel. b、van der waal's forces between stacked bases destabilizes the structure. c、the two strands are antiparallel. d、a, b, and z-dna forms are present in nature. e、only the b-dna form is present
2、【多选题】while studying the structure of a small gene that was recently sequenced during the human genome project, an investigator notices that one strand of the dna molecule contains 20a’s, 25g’s, 30c’s and 22t’s,how many of each base is found in the complete double-stranded molecule? a、a=40, g=50, c=60, t=44 b、a=44, g=60, c=50, t=40 c、a=45, g=45, c=52, t=52 d、a=50, g=47, c=50, t=47 e、a=42, g=55, c=55, t=42
3、【多选题】the linkage between nucleotides is a、2’,-3’ phosphodiester bond; b、3’,-5’ phosphodiester bond c、2’,-5’ phosphodiester bond; d、hydrogen bond e、peptide bond
5、【多选题】rna also has some structure. these include all of the following except: a、hairpin turns b、internal loops and bulges c、beta-helix d、right-handed double helix e、cloverleaf structure
6、【多选题】all of the following are true of the differences between dna and rna except: a、rna utilizes uracil (u) in place of thymine (t). b、rna has a 2'-oh whereas dna does not. c、the nucleotides in dna are linked 3'-5' by phosphodiester bonds but in rna they are linked 2'-5'. d、dna is usually double stranded and rna is usually single stranded. e、there is more rna than dna in the cell.
7、【多选题】the description of the secondary structure of dna double helix are correct, except a、two antiparallel strands b、deoxyribose-phosphate frame located outside the strands c、two strands are joined by hydrogen bond formed between a-t and g-c d、diameter of helix is 2 nm, and 10 bases in each turn e、nucleosome is the structure unit of dna double helix
8、【多选题】the hyperchromic effect refers to the increase in the uv absorption of dna. this is a result of: a、annealing b、melting of dna c、b to z-dna conversion. d、increased hydrogen bonding between strands. e、renaturation of dna
9、【多选题】the correct description about tm is a、the temperature at which half of the maximum absorbance value of dna at 260nm during heat denaturation b、the temperature at which maximum absorbance value of dna at 260nm during heat denaturation c、the optimum temperature for dna synthesis d、high tm value is related to low g-c content e、the temperature to form dna and rna hybrid molecule
10、【多选题】which of these three-letter codes is correct regarding the amino acid isoleucine? a、ile b、isl c、iso d、ilc
11、【多选题】in order to package the 3x109 nucleotides of dna into the nucleus, the dna is wound around histones. these are proteins that bind to the dna. the interaction of histones and dna involves: a、at, gc pairing between histones and dna b、h-bonding between arginine and lysine residues and the dna phosphate backbone c、basic residues of the histone and the phosphate backbone of dna d、proteolysis e、hydrophobic interaction
12、【多选题】the sequence of part of a dna strand is the following: -attcgattgcccacgt-. when this strand is used as a template for dna synthesis, the product will be which one of the following? a、taagctaacgggtgca b、uaagcuaacgggugca c、acgugggcaaucgaau d、acgtgggcaatcgaat e、tgcacccgttagctta
13、【多选题】if the coden of mrna is acg, then the anticoden of trna is a、ugc b、tgc c、gca d、cgu e、tgc
14、【多选题】small snrnps are involved in: a、translation b、mrna processing c、transcription d、catalysis of peptide bonds
15、【多选题】the template strand of dna is 5’-attcag-3 ’ , its transcript is a、5’ -gactta-3’ b、5’ -ctgaat-3’ c、5’ -uaaguc-3’ d、5’ -cugaau-3’ e、5’ - taagtc-3’
4.1前置问题及学习目标
1、【简答题】为什么对于乙肝患者治疗策略之一是大剂量补充复合维生素？
2、【简答题】举例说明酶的抑制剂在医学中的应用。
4.7必交作业
1、【简答题】a 47-year-old female is brought to the emergency department with complaints of malaise, nausea and vomiting, and fatigue. the patient reveals a long history of alcohol abuse for the last 10 years requiring drinks daily especially in the morning an an “eye opener.” she has been to rehab on several occasions for alcoholism but has not been able to stop drinking. she is currently homeless and jobless. she denies cough, fever, chills, upper respiratory symptoms, sick contacts, recent travel, hematemesis, or abdominal pain. she reports feeling hungry and has not eaten very well in a long time. on physical exam she appears malnourished but in no distress. her physical exam is normal. her blood count reveals a normal white blood cell count but does show an anemia with large red blood cells. her amylase, lipase, and liver function tests were normal. 1.what is the most likely cause of her anemia? 2.what is the molecular basis for the large erythrocytes?
2、【多选题】routine newborn screening identified a child with elevated levels of α-ketoacids of the branched-chain amino acids. a certain subset of such children will respond well to which of the following vitamin supplementation? a、niacin b、riboflavin c、b12 d、b6 e、thiamine
4、【多选题】a 50-year-old man has been trying to lose weight, but he enjoyed eating so much that he found it difficult to do so .he then reads about a product in the popular press, which guarantees that he can lose weight ,as caloric intake due to starch ingestion will be reduced ( a starch blocker). the over-the-counter product that he buys is claimed to inhibit which of the following enzymes? a、pancreatic trypsinogen b、pancreatic lipase c、salivary amylase d、gastric amylase e、intestinal enteropeptidase
5、【多选题】deficiency in which of the following vitamins will lead to a functional folate deficiency? a、thiamine b、niacin c、riboflavin d、b12 e、vitamin c
6、【多选题】in a laboratory study, volunteers were made experimentally vitamin b6 deficient, and much to the investigator’s surprise, a mild hypoglycemia, with ketosis, was noted. the hypoglycemia is a result of which of the following? a、inhibition of phosphoenolpyruvate carboxykinase b、inhibition of pyruvate carboxylase c、reduced activity of glucose-6-phosphatase d、reduced activity of liver glycogen phosphorylase e、reduced insulin secretion
9、【多选题】a newborn has milky white skin, white hair, and red-appearing eye color (see the figure below).this disorder most often results from a defect in which of the following enzymes a、phenylalanine b、nadph oxidase c、dihydrofolate d、tyrosinase e、homogentisic acid oxidase
1、【单选题】select the one false statement: a、marfan syndrome is due to mutations in the gene encoding fibrillin-1, a major constituent of microfibrils. b、all cases of ehlers–danlos syndrome are due to mutations affecting the genes encoding the various types of collagen. c、laminin is found in renal glomeruli along with entactin, type iv collagen, and heparin or heparan sulfate. d、mutations affecting type iv collagen can cause serious renal disease. e、mutations in the collagen 1a1 gene can cause osteogenesis imperfecta.
2、【单选题】regarding the abo blood group substances, select the one false statement: a、they can be either glycosphingolipids or glycoproteins, depending on location. b、individuals with blood group ab have antibodies to both a and b blood group substances. c、blood group h substance is formed from its precursor by the action of a fucosyltransferase. d、blood group b is formed from its precursor by the action of a galactosyltransferase. e、individuals of blood group o lack the galactosyltransferase.
3、【单选题】a male infant is failing to thrive and, on examination, is noted to have hepatomegaly and splenomegaly, among other findings. urinalysis reveals the presence of both dermatan sulfate and heparan sulfate. you suspect the patient has hurler syndrome. from the following list, select the enzyme that you would wish to have assayed to support your diagnosis: a、-glucuronidase. b、-galactosidase. c、-l-iduronidase d、-n-acetylglucosaminidase e、neuraminidase
4、【单选题】all of the following sugars are found in glycoproteins except: a、fructose b、fucose c、galactose d、mannose e、xylose
5、【单选题】select the one false statement: a、mucins contain predominantly o-linked glycans. b、o-linked sugar chains are built up by the stepwise donation of sugars from nucleotide-sugars. c、dolichol-pyrophosphate–oligosaccharide donates all of the sugars found in mature n-linked glycoproteins. d、n-acetylneuraminic acid is commonly found at the termini of n-linked sugar chains. e、calnexin retains partly folded or misfolded proteins in the er until proper folding has occurred.
1、【简答题】case file study（you can answer the question either in chinese or english) a 50-year-old hispanic female presents to your clinic with complaints of excessive thirst, fluid intake, and urination. she denies any urinary tract infection symptoms. she reports no medical problems, but has not seen a doctor in many years. on examination she is an obese female in no acute distress. her physical exam is otherwise normal. the urinalysis revealed large glucose, and a serum random blood sugar level was 320mg/dl. 1.what is the most likely diagnosis? 2.what other organ systems can be involved with the disease? 3.what is the biochemical basis of this disease?
1、【单选题】which of the following glycolytic enzymes is used in gluconeogenesis? a、glucokinase b、phosphofructokinase 1 c、pyruvate kinase d、aldolase e、none of them
2、【单选题】which coenzyme in pyruvate dehydrogenase complex serves as the final hydrogens acceptor? a、fad b、lipoate c、nad d、tpp e、nadp
3、【单选题】the synthesis of glucose from pyruvate by gluconeogenesis: a、occurs exclusively in the cytosol. b、is inhibited by an elevated level of glucagon. c、requires the participation of biotin. d、involves lactate as an intermediate. e、requires the oxidation/reduction of fad.
4、【单选题】which enzyme is the key enzyme in glycogenolysis (glycogen degradation) ? a、phosphorylase b、hexokinase c、phosphoenol pyruvate carboxykinase d、hmg-coa reductase e、pyruvate kinase
5、【单选题】epinephrine and glucagon have which one of the following effects on glycogen metabolism in the liver? a、the net synthesis of glycogen is increased. b、glycogen phosphorylase is activated, whereas glycogen synthase is inactivated. c、both glycogen phosphorylase and glycogen synthase are activated but at significantly different rates. d、glycogen phosphorylase is inactivated, whereas glycogen synthase is activated. e、camp-dependent protein kinase is activated, whereas phosphorylase kinase is inactivated.
6、【单选题】the principl function of the tca cycle is to a、generate co2 b、transfer electrons from the acetyl portion of acetyl coa to nad and fad c、oxidize the acetyl portion of acetyl coa to oxaloacetate d、generate heat from the oxidation of the acetyl portion of acetyl coa e、dispose of excess pyruvate and fatty acids
7、【单选题】the compound which can not be converted into glucose in animals is. a、lactate b、pyruvate c、glycerol d、fatty acid e、glycine
8、【单选题】which one of the following statements concerning glycolysis is correct? a、the conversion of glucose to lactate requires the presence of oxygen. b、hexokinase is improtant in hepatic glucose metabolism only in the absorptive period following consumption of a carbohydrate-containing meal. c、fructose 2,6-bisphosphate is a potent inhibitor of phosphofructokinase. d、the rate-limiting reactions are also the irreversible reaction. e、the conversion of glucose to lactate yields two atp and two nadh
9、【单选题】most of the reducing equivalents utilized for synthesis of fatty acids can be generated from a、the pentose phosphate pathway b、glycolysis c、the citric acid cycle d、mitochondrial malate dehydrogenase e、citrate lyase
10、【单选题】in which compartment of the cell does glycolysis occur? a、mitochondrion b、nucleus c、soluble cytoplasm (cytosol) d、rough endoplasmic reticulum e、smooth endoplasmic reticulum
11、【单选题】which one of the following is a condition that decreased the oxidation of acetyl coa by the citric acid cycle? a、a low atp/adp ratio b、a low nadh due to rapid oxidization to nad through the respiratory chain c、a low nad /nadh ratio d、a high concentration of amp e、a low gtp/gdp ratio
12、【单选题】nadh is required for the one-step reaction by which pyruvate is converted to a、oxaloacetate b、acetyl coa c、phosphoenolpyruvate d、lactate e、none of them
13、【单选题】an infant with an enlarged liver has a glucose 6-phosphatase deficiency. this infant a、cannot maintain blood glucose levels either by glycogenolysis or by gluconeogenesis b、can use liver glycogen to maintain blood glucose levels c、can use muscle glycogen to maintain blood glucose levels d、can convert both alanine and glycerol to glucose to maintain blood glucose levels e、none of them
14、【单选题】the degradation of glycogen normally produces a、more glucose than glucose l-phosphate b、more glucose 1-phosphate than glucose c、equal amounts of glucose and glucose 1-phosphate d、neither glucose nor glucose l-phosphate e、only glucose l-phosphate
15、【单选题】a two year-old boy was brought into the emergency room, suffering from severe fasting hypoglycemia. on physical examination, he was found to have hepatomegaly. laboratory tests indicated that he also had hyperlacticacidemia and hyperuricemia. a liver biopsy indicated that hepatocytes contained greater than normal amounts of glycogen that was of normal structure. the child was subsequently found to be missing which of the following enzymes? a、glycogen synthase b、glycogen phosphorylase c、glucose 6-phosphatase d、amylo-α (1→ 6)-glucosidase e、amylo-α (1→ 4) → α (1→ 6)-transglucosylase
16、【单选题】the unique pathway for mature red blood cells to obtain atp is a、pentose phosphate pathway b、tricarboxylic acid cycle c、β-oxidation of fatty acid d、glycolysis e、gluconeogenesis
17、【单选题】how many net molecules of atp are generated in the conversion of glucose to pyruvate? a、0 b、1 c、2 d、3 e、4
18、【单选题】which of the following statements about glycolysis is true? a、glucokinase catalyzes the conversion of glucose to glucose 6-phosphate in the liver b、phosphofructokinase 1 catalyzes the conversion of fructose 1,6-bisphosphate to dihydroxyacetone phosphate c、when one molecule of glucose is converted to pyruvate via glycolysis, one molecule of nadh is reduced d、when one molecule of glucose is converted to pyruvate via glycolysis, one carbon is lost as co2 e、hexokinase catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate
19、【单选题】the pentose phosphate pathway generates each of the following products except a、nadph, which may be used for fatty acid synthesis b、ribose 5-phosphate, which may be used for the biosynthesis of atp c、compounds that are intermediates of glycolysis d、xylulose 5-phosphate by one of the nonoxidative reactions e、glucose from ribose 5-phosphate and co2
20、【单选题】which of the following metabolic pathway take place in the mitochondira? a、a.glycolytic pathway b、the synthesis of ketone body c、pentose phosphate pathway d、the synthesis of the fatty acid e、the synthesis of the glycogen
7.1前置问题及学习目标
1、【简答题】呼吸链的组成顺序
2、【简答题】动物冬眠时如何维持体温？
3、【简答题】胞质中的nadh是如何参与氧化磷酸化的？
7.5必交作业
1、【简答题】case file study（you can answer the question either in chinese or english) a 68-year-old female in a hypertensive crisis is being treated in the intensive care unit (icu) with intravenous nitroprusside for 48 hours. the patient’s blood pressure was brought back down to normal levels; however, she was complaining of a burning sensation in her throat and mouth followed by nausea and vomiting, diaphoresis, agitation, and dyspnea. the nurse noticed a sweet almond smell in her breath. an arterial blood gas revealed a significant metabolic acidosis. a serum test suggests a metabolite of nitroprusside, thiocyanate, is at toxic levels. 1.what is the likely cause of her symptoms? 2.what is the biochemical mechanism of this problem? 3.what is the treatment for this condition?
1、【单选题】which of following subunit is mainly responsible to catalyze the synthesis of atp in atp synthase? a、α b、β c、γ d、ε e、c
3、【单选题】what is the consequence of thermalgenin effect. a、producing more heat b、etc is inhibited c、producing more atp d、oxidative phosphorylation is increased e、none of the above
5、【单选题】why does the oxidation of nadh lead to roughly 3 atps, while fadh2 oxidation produces only about 2 atps? a、fadh2 enters the electron transport chain later than nadh. b、the 2 hydrogens in fadh2 go directly to the synthesis of 2 atps. c、more nadh is produced during metabolism. d、fadh2 is only important in fatty acid oxidation. e、redox potential change is only sufficient for production of 2 atps.
7、【单选题】the electron transport chain is made up of four segments (complexes i-iv with o2 as the final electron acceptor). which statement best describes the electron transport chain a、each component involves a phosphorylation step. b、each complex directly transfers electrons to o2. c、electrons flow spontaneously from one carrier to the next. d、fe-s cluster acts as a important coenzyme in complex. e、locate in outer membrane of mitochondria
8、【单选题】a research was studying oxidative phosphorylation in a suspention of carefully washed and isolated mitochondria atp, adp, inorganic phosphate, lactate, lactate dehydrogenase, and oxygen were introduced to the suspension, and he was able to demonstrate atp production within the mitochondria.the research we then added oligomycin to the mixture, which stopped oxygen uptake. this occurred due to which of the following? a、inhibition of complex ⅰ b、inhibition of complex ⅱ c、inhibition of complex ⅲ d、inhibition of complex ⅳ e、inhibition of the proton translocating atpase
9、【单选题】the electron transport chain is made up of four segments (complexes i-iv with o2 as the final electron acceptor). which statement best describes the electron transport chain? a、each component involves a phosphorylation step. b、each complex directly transfers electrons to o2. c、electrons flow spontaneously from one carrier to the next. d、every complex has a fe-s cluster. e、locate in outer membrane of mitochondria
1、【简答题】a 48-year-old male presents to the clinic because of concerns about heart disease. he reports that his father died from a heart attack at age 46, and his older brother has also had a heart attack at age 46 but survived and is on medications for elevated cholesterol. the patient reports chest pain occasionally with ambulation around his house and is not able to climb stairs without significant chest pain and shortness of breath. the physical exam is normal, and the physician orders an electrocardiogram (ecg), exercise stress test, and blood work. patient’s cholesterol result comes back as 350mg/dl (normal 200). the physician prescribes medication, which he states is directed at the rate-limiting step of cholesterol biosynthesis. what is the rate-limiting step of cholesterol metabolism? what is class of medication prescribed?
1、【单选题】all of the following are derived from cholesterol except: a、bile salts b、progesterone c、glucocorticoids d、squalene e、mineralocorticoids
2、【单选题】a newborn infant had trouble breathing at birth. the infant was 3 months premature. the physicians treated the infant with a solution, which was directly injected into the lungs. within seconds, the infant responded with much improved breathing. a major component of this solution is which one of the following? a、dipalmitoyl phosphatidylcholine b、palmitate containing ceramide c、sphingosine d、sphingomyelin e、diacylgylycerol
3、【单选题】you are examining a patient who exhibits fasting hypoglycemia and need to decide between a carnitine deficiency and a carnitine acyltransferase 2 deficiency as the possible cause. you order a blood test to specifically examine the levels of which one of the following? a、glucose b、ketone bodies c、insulin d、acyl-carnitine e、carnitine
4、【单选题】which one of the following statements concerning chylomicrons is correct? a、chylomicrons are made inside intestinal cells and secreted into lymph, where they acquire apolipoproteins b and c. b、the core of chylomicrons contains triacylglycerol and phospholipids. c、the enzyme hormone sensitive lipase acts on chylomicrons to release fatty acids from triacylglycerol when they are bound to the surface of endothelial cells in blood capillaries. d、chylomicron remnants differ from chylomicrons in that they are smaller and contain a lower proportion of triacylglycerol. e、chylomicrons are taken up by the liver.
5、【单选题】a patient presents in your office with very high levels of serum cholesterol. after a series of tests, you conclude that the patient has high circulating levels of ldl cholesterol, but has normal levels of the liver ldl receptor. one possible explanation for this observation is which of the following? a、the patient has a mutated form of apoprotein b-100. b、the inability to selectively remove cholesterol from the ldl complex. c、the absence of the enzyme lipoprotein lipase. d、decreased levels of acyl-coa: cholesterol acyltransferase e、altered phosphorylation of the ldl receptor.
6、【单选题】a patient presents in your office with very high levels of serum cholesterol. he states that he has tried to follow the diet and exercise regimen you gave him last year. you decide that this patient would benefit from a drug such as lipitor (atorvastatin). this class of drugs is effective in treating hypercholesterolemia because it has what effect? a、a.stimulates phosphorylation of the β-hydroxyl-β-methylglutaryl-coa reductase enzyme b、decrease the stability of theβ-hydroxyl-β-methylglutaryl-coa reductase protein c、binds cholesterol preventing it from being absorbed by the intestine d、directly prevents the deposition of cholesterol on artery walls e、inhibits the enzymeβ-hydroxyl-β-methylglutaryl-coa reductase
7、【单选题】the rate-limting enzyme in the β-oxidation of fatty acid is a、acyl coa synthetase b、carnitine acyltransferase i c、carnitine acyltransferase ii d、acyl coa dehydrogenase e、hydroxyacyl coa dehydrogenase
8、【单选题】after they are produced from acetyl-coa in the liver, ketone bodies are mainly used for which one of the following processes? a、excretion as waste products. b、energy generation in the liver. c、conversion to fatty acids for storage of energy. d、generation of energy in the tissues. e、generation of energy in red blood cells.
9、【单选题】under condition of starvation, the major fuel for the brain is a、blood glucose b、fatty acids c、ketone bodies d、amino acids
10、【单选题】which is the following can transfer acetyl group from mitochondria to cytoplasm a、acetyl-coa b、acetyl-carnitine c、succinate d、citric acid e、oxaloacetate
11、【单选题】the class of drugs called statins have proved very effective against hypercholesterolemia, a major cause of atherosclerosis and associated cardiovascular disease. these drugs reduce plasma cholesterol levels by: a、preventing absorption of cholesterol from the intestine. b、increasing the excretion of cholesterol from the body via conversion to bile acids. c、inhibiting the conversion of 3-hydroxy-3-methylglutaryl-coa to mevalonate in the pathway for cholesterol biosynthesis. d、increasing the rate of degradation of 3-hydroxy-3-methylglutaryl coa reductase. e、stimulating the activity of the ldl receptor in the liver.
12、【单选题】the subcellular site of the breakdown of long chain fatty acids to acetyl-coa via -oxidation is: a、the cytosol b、the matrix of the mitochondria c、the endoplasmic reticulum d、the mitochondrial intermembrane space e、e.the golgi apparatus
13、【单选题】a 19-year-old man complains of “brown urine” and pain in the muscles of his arms and legs experienced while playing touch football. he has had several episodes of muscle pain during exercise, but he had not noticed darkening of his urine afterward. the pain usually resolved overnight. physical examination reveals a well-fed male of normal stature. reflexes and range of motion in all arms and legs are normal, but there is some paraparesis (weakness), especially in his right leg. a muscle biopsy is taken and sent for specialized resting. the patient is sent home with a recommendation to take a dietary carnitine supplement. which of the following is the most likely diagnosis? a、medium-chain fatty acyl coa dehydrogenase (mcad) deficiency b、carnitine deficiency c、carnitine palmitoyltransferases i deficiency d、carnitine palmitoyltransferases ii deficiency e、marfan syndrome
14、【单选题】the activated choline required for the lecithin biosynthesis is a、adp- choline b、cdp- choline c、gdp- choline d、udp- choline
15、【单选题】in humans, obesity is not caused by leptin levels, but by malfunctioning signal mechanisms. which of the following do you think might be affected by high leptin concentrations binding to receptor? a、activation of acetyl coa to malonyl coa b、lipase c、phosphate pentose pathway d、cholesterol synthesis
16、【单选题】synthesis of fatty acids occurs in the cytoplasm, and is catalyzed by fatty acid synthase. in animals, fatty acid synthase is a homodimer, with each chain approximately 250,000 daltons in size. the two chains are linked head to tail. all of the components of fatty acid synthase, including acyl carrier protein (acp) and β-ketoacyl acp synthase, are contained within the two chains. reactions occur in the space between the two chains, an arrangement that keeps the reactants in one place. the first round of synthesis produces a 4-carbon unit. from here, two carbons are added until the final product, palmitate is made. how many rounds does it take to make palmitate? a、14 b、10 c、7 d、2 e、cannot be determined
17、【单选题】the compound which can not be oxidized into co2 and h2o in vivo is a、acetoacetate b、lactate c、glycerol 3-phosphate d、cholesterol
18、【单选题】which one of the following statements about the absorption of lipids from the intestine is correct? a、dietary triacylglycerol is partially hydrolyzed and absorbed as free fatty acids and monoacylglycerol. b、dietary triacylglycerol must be completely hydrolyzed to free fatty acids and glycerol before absorption. c、release of fatty acids from triacylglycerol in the intestine is inhibited by bile salts. d、fatty acids that contain ten carbons or less are absorbed and enter the circulation primarily via the lymphatic system. e、formation of chylomicrons does not require protein synthesis in the intestinal mucosa
19、【单选题】in liver, large numbers of acetyl coa derived from fat mobilization convert mainly into a、glucoses b、cholesterols c、fatty acids d、ketone bodies e、cholesterol esters
20、【单选题】a 7-year-old girl has 1 1-month history of foul-smelling diarrhea. upon further inquiry, the frequency seems to be 4-6 stools per day. she has also had trouble seeing at night in the past2 weeks. her wbc count is normal. physical examination is entirely normal. examination of a stool sample reveals that it is bulky and greasy. analysis does not reveal any pathogenic microorganisms or parasites but confirms the presence of fats. further evaluation of this patient would likely reveal which of the following conditions? a、lactose intolerance b、biliary insufficiency c、ileal disease d、diabetes e、giardiasis
21、【单选题】rate-limiting enzyme in the synthesis of ketone bodies is a、thiolase b、hmg-coa synthase c、hmg-coa lyase d、β-hydroxybutyrate dehydrogenase
9.1前置问题及学习目标
1、【简答题】何为苯丙酮酸尿症？发病原因？
2、【简答题】为什么天冬酰胺酶能够用来治疗白血病？
3、【简答题】简述氨的来源和去路
4、【简答题】为什么检测血中谷丙转氨酶浓度能够指示肝脏损伤？
9.6必交作业
1、【简答题】case file study（you can answer the question either in chinese or english) a 1-year-old girl is brought to her pediatrician’s office with concerns about her development. she had an uncomplicated birth outside the united states at term. the mother reports that the baby is not achieving the normal milestones for a baby of her age. she also reports an unusual odor to her urine and some areas of hypopigmentation on her skin and hair. on exam, the girl is noted to have some muscle hypotonia and microcephaly. the urine collected is found to have a “mousy” odor 1.what is the most likely diagnosis? 2.what is the biochemical biasis of the hyporpigmented skin and hair?
1、【单选题】which of the following are the nitrogen source of urea ? a、carbomoyl phosphate and aspartate b、carbomoyl phosphate and ornithine c、α-amino group and γ-amino group of ornithine d、α-amino group of citrulline and α-amino group of arginine e、γ-amino group of ornithine and glycine
2、【单选题】which of the following amino acid can produce paps? a、taurine b、methionine c、cysteine d、homocysteine e、glutamate
3、【单选题】mr smith had been prescribed a drug to treat his depression. one of the effects of the drug is to maintain elevated levels of a particular neurotransmitter that has been derived from which of the following amino acids? a、tryptophan b、tyrosine c、glutamate d、histidine e、glycine
4、【单选题】the major fate of ammonia is ( ) in the body. a、to synthesize nonessential amino acids b、to synthesize glutamine c、to synthesize urea d、to synthesize alanine e、to synthesize nucleotides
5、【单选题】the most important role of s-adenosyl methionine (sam) is. a、to provide methionine b、to synthesize tetrahydrofolate c、to synthesize purine nucleotides d、to synthesize pyrimidine nucleotides e、to supply methyl group
6、【单选题】which of the following is not produced by tyr? a、norepinephrine b、epinephrine c、dopamine; d、phe e、melanin
7、【单选题】which of the following state is positive nitrogen balance? a、advanced cancer b、pregnant women c、people suffer from fever d、people suffer form long-time hunger e、normal adult
8、【单选题】which of the following amino acid can not produce one carbon unit? a、serine b、valine c、tryptophan d、histidine e、glycine
9、【单选题】which of the following amino acids can be converted into taurine in the body? a、cysteine b、glycine c、methionine d、threonine
10、【单选题】which of the following is the main deamination style in the body? a、oxidation deamination b、reduction deamination c、direct deamination d、transamination; e、union deamination
11、【单选题】when compared to his state after an overnight fast, a person who fasts for 1 week will have a、higher levels of blood glucose b、less muscle protein c、more adipose tissue d、lower levels of ketone bodies in the blood e、none of the above
12、【单选题】which one of the following amino acids is essential in the human diet? a、serine b、lysine c、glutamate d、tyrosine e、cysteine
13、【单选题】in the presence of hyperammonia, production of which of the following amino acids is always increased? a、glycine b、arginine c、proline d、histidine e、glutamine
14、【单选题】the primary manner for the deamination of amino acids in muscle involves. a、purine nucleotide cycle b、oxidative deamination of glutarate c、transamination d、ornithine cycle e、conjunction of transamination and oxidative deamination
15、【单选题】the compound which does not belong to one carbon unit as follow is. a、-ch3 b、=ch2 c、=ch- d、co2
16、【单选题】which of the following is the carrier of one carbon unit ? a、biotin b、sam c、fh4 d、fh2 e、folic acid
17、【单选题】which of the following state is nitrogen equilibrium? a、advanced cancer patient b、pregnant women c、patient recovering from illness d、people suffer form long-time hunger e、normal adult
18、【单选题】the transportation form of ammonia in blood is a、glutamate b、tyrosine c、glutamine d、glutathionine e、aspartate
19、【单选题】which of the following is the direct donor of ch3? a、n5-ch3-fh4 b、sam c、n5,n10- ch2-fh4 d、n5,n10=ch-fh4 e、fad
20、【单选题】which of the following is the process that transport ammonia from muscle to liver? a、tac cycle b、ornithine cycle c、alanine-glucose cycle d、methionine cycle e、γ-glutamyl cycle
10、【单选题】select the one of the following statements that is not correct : a、the bohr effect refers to the release of protons that occurs when oxygen binds to deoxyhemoglobin. b、shortly after birth of the human infant synthesis of the α-chain undergoes rapid induction until it c、the β-chain id fetal hemoglobin is present throughout gestation. d、thalassemias are genetic defects due to partial or total absence of the α- or β-chains of hemoglobin e、the taut conformation of hemoglobin is stabilized by several salt bridges that form between the subunits.
13.1前置问题及学习目标
1、【简答题】试述dna发生嘧啶二聚体的机制及其完整的修复过程。
13.9必交作业
1、【单选题】why mammalian genomes are 100 times the size of bacterial genomes yet are replicated in just a few minutes. which of the following best explains this fact? a、eukaryotic dna polymerases are extraordinarily fast compared with prokaryotic polymerases. b、the higher temperature of mammalian cells allows for an exponentially higher replication rate. c、the presence of histones in mammalian chromatin speeds up the rate of dna replication. d、histones and micrornas complexed with bacterial dna speed up the rate of dna replication. e、hundreds of replication forks work simultaneously on each piece of mammalian genomic dna.
2、【单选题】a 2-year-old child presents with poor weight gain, sparse hair, unusual face with sunken eyes, and skin that reddens markedly in sunlight. a diagnosis of cockayne syndrome (mim*216400) is considered and studies of dna synthesis are undertaken. in vitro assay of labeled thymidine incorporation reveals decreased levels of dna synthesis compared to controls, but normal-sized labeled dna fragments. the addition of protein extract from normal cells gently heated to inactivate dna polymerase restores dna synthesis in cockayne cells to normal. which of the following enzymes used in dna replication is most likely to be defective in cockayne syndrome? a、unwinding proteins b、dna-directed rna polymerase c、dna polymerase i d、dna ligase e、dna-directed dna polymerase
3、【单选题】part of the triplet genetic code involving mrna codon triplets that start with u is shown below. using the portion of the genetic code shown, which of the following mutations in the 3' to 5' dna template segments corresponds to a nonsense mutation? a、acgacgacg to acaaacacg b、agaataaca to aaaataaca c、aacaacaac to aacaagaac d、aaaatgagc to aaaataagc e、aggaatatg to aggaatatt
4、【单选题】replication of dna starts with the unwinding of the entire dna molecule. each original strand is a therefore a template from which a new strand is synthesized based on complementary base pairing by dna polymerase. the new dna consists of an old parent strand and a new daughter strand. this process is called: a、hydrolytic cleavage b、helical pairing c、semiconservative replication d、heredity
5、【单选题】dna replication results in: a、protein production b、two new daughter strands c、heavy dna d、induced mutations e、mrna transcripts
6、【单选题】dna replication is semiconservative. why do you think this is true? a、requires less energy b、c、 d、 b、only one dna strand can be copied at a time. c、increased fidelity d、dna replication starts at specific sites only. e、rna primer limitations
7、【单选题】why does lagging strand synthesis consist of discontinuous okazaki fragments? a、a、there is a shortage of dntps for lagging strand synthesis. b、okazaki fragments are riddled with mistakes; proofreading enzymes chop up the nucleotide into short fragments. c、lagging strand dna polymerase can only handle a few nucleotides at a time. d、dna is synthesized 5' to 3'. replication can only proceed from the unwound portion of dna outward.
8、【单选题】single-stranded binding proteins (ssb) bind to the outer backbone of dna during replication. what would you predict about ssbs? a、they contain arginine and lysine residues. b、they hydrolyze phosphodiester bonds. c、sequence-specific binding d、they form covalent bonds to sugars.
9、【单选题】telomerase contains a ribozyme. a、telomerase contains a ribozyme. b、telomerase adds a repeating sequence to the 5' end of dna c、telomerase activity decreases as the cell ages. d、telomerase adds a repeating sequence to the 3' end of dna. e、telomerase is found only in eukaryotes.
10、【单选题】dna replication is not perfect; a mistake is made for every 104 to 105 nucleotides added. however, there are proofreading enzymes that excise incorrect bases and insert the correct one. which of the following enzymes proofread dna? a、dna ligase b、dna gyrase c、dna ii d、topoisomerase e、dna polymerase i and iii
11、【简答题】case study a 2-year-old scottish-american girl presents with deeply pigmented and scarred skin and her growth is delayed. her dermatologist obtains a skin biopsy: slightly hyperkeratosis, irregular thickening and shrinking in spinus layer, many irregular basal tumor cell mass are observed in dermis. what is the most likely diagnosis? what is the molecular genetics behind this disorder? what is the pathophysiologic mechanism of her symptoms?
14.1前置问题及学习目标
1、【简答题】试述mrna转录后的加工方式及apob100和apob48两种蛋白质的合成机制。
14.7必交作业
1、【单选题】lipoproteins transport lipids from intestine and liver where they are absorbed and metabolized to peripheral tissues via the bloodstream. they contain core proteins (apo proteins) that bind various types of lipid, thus producing lipoprotein complexes of varying densities—very low density lipoproteins (vldl), low density lipoproteins (ldl), and high density lipoproteins (hdl) after plasma lipoprotein electrophoresis. a disorder called abetalipoproteinemia (mim*200100) was distinguished by its deficiency of the bands for very low density lipoproteins (vldl) and low density lipoproteins (ldl) after plasma electrophoresis. affected patients have ataxia (wide gait, incoordination), retinopathy (retinal degeneration with blindness), and myopathy (muscle weakness). vldl and ldl contain the same apob core protein, their different densities produced by association with different lipids, and apob became good candidate for mutation in the disorder. initial characterization of the apob gene together with its mrna and protein products demonstrated identical mrna sizes in all tissues. western blotting using antibody specific for the amino-terminus of apob protein showed a 100-kda species in liver and a 48-kda species in intestine, as did antibody specific for the c-terminus of the 48-kda intestinal protein. molecular study of a patient with abetalipoproteinemia showed normal mrna sizes, but 100-kda peptide species were identified in both liver and intestine using the amino- or carboxy-terminus antibody probes. which of the following processes is most likely deficient in this patient with apobetalipoproteinemia? a、rna splicing b、dna amplification c、transcription initiation d、rna editing e、transcription factor phosphorylation
2、【单选题】if the dna strand shown below is used as a template for rna polymerase, what would be the sequence of the resultant mrna following transcription? 5'-cattccatagcatgt-3' a、5'-uguacgauaccuuac-3' b、5'-cauuccauagcaugu-3' c、5'-guaagguaucguaca-3' d、5'-acaugcuauggaaug-3'
3、【单选题】all of the following are true of rna polymerase except: a、catalyze the synsthesis of rna. b、it binds best to promoter regions. c、it has proofreading capability. d、it requires no primers. e、it can be inhibited by rifampicin.
4、【单选题】a careful analysis of cellular components discovers short-lived rna species in which an adenine nucleotide is found with three phosphodiester bonds (linked to the 2’, 3’, and 5’ carbons). this transient structure is formed during which of the following processes? a、mrna cap formation b、c、 d、 e、spl b、mrna polyadenylation c、transcription of rrna d、transcription of micrornas e、splicing of hnrna
5、【单选题】a patient suffering from chills, vomiting, and cramping was rushed to the emergency department. he had eaten wild mushrooms for dinner that he had picked earlier in the day. his symptoms are due to an inhibition of which of the following enzymes? a、rna polymerase ⅰ b、telomerase c、rna polymerase ⅲ d、rna polymerase ⅱ e、dna primase
6、【单选题】an intestinal cell line was being studied for its ability to produce lipid-containing particles. surprisingly, a mutated variant of this cell line was unable to do so. western blot analysis yielded a protein with the same size as apolippprotein b100. a potential mutation in this cell line, which would lead to this result, is which of the following? a、rna editing defect b、cap formation altered c、splicing defect d、inefficicient poly-a tail addition e、promoter alteration
7、【单选题】a man with a bacterial infection was prescribed rifampin to resolve the infection. rifampin does not affect eukaryotic cell due to which of the following? a、differences in ribosome structure between eukaryotes and prokaryotes b、differences in snrnp structure between eukaryotes and prokaryotes c、differences in transcription factors between eukaryotes and prokarytoes d、inability of the drug to bind to dna containing nucleosomes e、structureal differences in rna polymerase between eukaryotes and prokaryotes
8、【单选题】small snrnps are involved in: a、translation b、transcription c、mrna processing d、catalysis of peptide bonds
9、【单选题】all of the following are true of rna polymerase except: a、it binds to most regions of dna. b、it is inhibited by rifampicin in prokaryote. c、it catalyze the synthesis of phosphodiester between ntp. d、it produces transient rna-dna hybrids. e、it has no proofreading capability.
10、【单选题】the site to which rna polymerase binds on the dna template prior to the initiation of transcription. a、intro/exon junction b、open reading frame dna the terminator c、promoter d、initiator methionine codon e、terminator
11、【简答题】case study a 25-year-old mediterranean female presents to her obstetrician at 12-weeks gestation for her first prenatal visit. this is her first pregnancy, and she is concerned about her baby and the risk of inheriting a “blood ” disease like others in her family. the patient reports a personal history of mild anemia but nothing as severe as her brother who required frequent transfusions and died at age 10. the patient was told by her physician that she did not need to take iron supplementation for her anemia. patient deny having any anemic symptoms. her physical exam is consistent with a 12-week pregnancy and ultrasound confirmed an intrauterine pregnancy at 12-weeks gestation. the patient’s hemoglobin level shows a hypochromic, microcytic( small sized red cell) anemia( hemoglobin, 9g/dl) and hemoglobin electrophoresis demonstrated increased hemoglobin a2 level( 4.0 percent) and increased fetal hemoglobin level, a pattern consistent with β thalassemia minor. the patient underwent chorionic villus sampling to assess whether the fetus was affected, and the diagnosis returned in several hours. what is the molecular genetics behind this disorder? what was the likely test and what is the biochemical basis?