Protein Structure and Function PDF

Which of the following applies to the structure of the isoleucine side chain? - Contains the sulfhydryl group + Contains a branched hydrocarbon chain - Contains an aromatic ring - Contains a positively charged side chain Which of the following applies to the structure of the phenylalanine side chai...

Which of the following applies to the structure of the isoleucine side chain? - Contains the sulfhydryl group + Contains a branched hydrocarbon chain - Contains an aromatic ring - Contains a positively charged side chain Which of the following applies to the structure of the phenylalanine side chain? - Contains the sulfhydryl group - Contains a branched hydrocarbon chain + Contains an aromatic ring - Contains a positively charged side chain Which of the following applies to the structure of the methionine side chain? - Contains the sulfhydryl group - Contains a branched hydrocarbon chain - Contains an aromatic ring + Contains a sulfomethyl group Which of amino acids has the basic properties? - Leucine - Threonine + Histidine - Tryptophan Stereoisomers exist for all amino acids, except: - Arginine + Glycine - Serine - Leucine Lysine, arginine and have no charge in the weakly alkaline medium: - Aspartate - Glutamine + Histidine - Glutamate All of these amino acids are hydrophobic (nonpolar), except: + Lysine - Tryptophan - Phenylalanine - Leucine The primary structure of the protein is: - The amino acid composition of the polypeptide chain - The linear structure of the polypeptide chain formed by covalent bonds between amino acid side chains + The linear sequence of amino acids joined by peptide bonds in a protein - The structure of the polypeptide chain stabilized by hydrogen bonds between the atoms of the peptide backbone The primary structure of a protein: - Is stabilized by covalent bonds between amino acid side chains + Is stabilized by peptide bonds that are formed between the α-amino and α- carboxyl groups of amino acids - Is stabilized by hydrogen bonds between the atoms of the peptide backbone - Is formed due to the interaction between structural and functional domains The basis of the protein primary structure is: + Polypeptide chain - Polynucleotide chain - Domain - Subunit What types of relationships or interactions are characteristic of the protein primary structure? - Bond between the carboxyl and amino groups of amino acid side chains + The relationship between α-amino and α-carboxyl groups of amino acids - The hydrogen bonds between the peptide groups - Hydrophobic interactions between amino acid side chains Peptide bond in a protein: + Has a partial double character - Is a non-covalent - Is freely rotatable - Has a cis-conformation in the α-helix Salting-out is one of the methods used for protein isolation. Which protein properties most dependent on the concentration of salts? - The protein total charge + The degree of hydration of protein - The size of the protein molecule - The shape of the protein molecule To obtain a native protein one can use the following method: - Sedimentation by organic acids + Sedimentation by salts of alkaline-earth metals - Sedimentation by salts of heavy metals - Sedimentation by inorganic acids Which of these methods results in a reversible precipitation of the protein? - Precipitation with silver nitrate (AgNO3) - Precipitation with sulfosalicylic acid - Precipitation in the presence of nitric acid + Precipitation in the presence of ammonium sulfate – (NH4)2SO4 Choose a salt for reversible protein precipitation: + Ammonium sulfate - Silver nitrate - Mercury chloride - Lead acetate Choose a salt for irreversible protein precipitation: - Ammonium sulfate - Magnesium sulfate + Silver nitrate - Sodium chloride What happens to the protein at high temperature in the presence of hydrochloric acid? - The reversible precipitation - Salting-out - Electrophoresis + Hydrolysis One of the steps in studying the protein amino acid composition is its splitting into smaller peptides. For this purpose it is possible to use: + Chymotrypsin - Arginase - Aminopeptidase - Urease The interaction is the basis of Western blot: - DNA-DNA - DNA-RNA - RNA-RNA + Antigen-antibody An antibody labeled with an enzyme or isotope is called: - Oxygen probe - Atomic probe + Molecular probe - Nucleic probe AIDS diagnosis by Western blot analysis includes all of the steps, except: - Applying the molecular probe - Separation of proteins by molecular weight - Autoradiography + Salting-out of proteins The mixture of proteins was treated with sodium dodecyl sulfate and subjected to polyacrylamide gel electrophoresis (PAGE). The protein mobility in this electrophoresis depends on: - The solubility in the gel - The interaction with antibodies - The charge + The molecular weight The mixture of proteins was treated with sodium dodecyl sulfate, applied to the polyacrylamide gel and separated by electrophoresis (PAGE). The proteins: - Moved to the cathode + Moved to the anode - Remained at start place - Did not penetrate into the gel What does “the protein tertiary structure” imply? + The arrangement of entire polypeptide chain in space - The local conformation of polypeptide chain - The specific sequence of amino acids in the chain - The association of several polypeptide chains All of these factors are important in formation of the protein tertiary structure (3-D), except: + The rotation of atoms around the peptide bond - Water environment - Hydrophobic interactions between amino acid side chains - Ionic bonds between amino acid side chains Which of the following refers to the secondary structure of the protein? - The amino acid sequence + The helical structure of the portion of the protein molecule - The connection of proteins with non-protein groups - The3-D arrangement of all amino acids in the protein Which of the following applies to the secondary structure of a protein? - Several α-helices + Local conformation of the polypeptide chain in the form of an antiparallel β- structure - It is formed due to interaction with the ligand - Functional domains The quaternary structure of protein is referred to as: - 3-D arrangement of the polypeptide chain + Location of protomers and the character of bonds between them in an oligomeric protein - The sequence of amino acids in the polypeptide chain - The combination of α-helices and β-sheets in the polypeptide chain Amino acid is involved in the formation of coordination bond between heme and globin in the hemoglobin molecule: - Glycine - Arginine + Histidine - Glutamine What type of bond is formed between the non-protein and protein part in the phosphoprotein molecule? - Ionic + Phosphoester - Hydrogen - Disulfide All of these proteins are conjugated, except: - Myoglobin - Transferrin + Albumin - Collagen Collagen is a conjugated protein. Its non-protein part contains: - Heme - Phosphoric acid residue - Metal ions + Glucose Which amino acid prevails in the structure of collagen? - Alanine - Serine - Lysine + Glycine Histone proteins and nucleic acids form bonds in nucleoproteins: - Hydrophobic + Ionic - Cordination - Peptide In lipoproteins, bonds are formed between the protein part and lipid: - Glycosidic + Hydrophobic - Peptide - Hydrogen The change in the protein conformation means: a) changing the amino acid sequence of the polypeptide chain b) changes in secondary and tertiary structure of the polypeptide chains c) replacement of a non-protein group in a conjugated protein to another one d) changing the relative position of subunits in an oligomeric protein after interaction with the ligand a, b, c a, b + b, d c, d Interaction between molecules is complementary in next cases: a) between protein and its ligand b) between protomers in the oligomeric protein c) between functionally related enzymes in the multienzyme complex d) between amino acid side chains in the formation of the tertiary protein structure + a, b, c a, b, d b, c, d only b Choose the correct statements about the relationship between hemoglobin structure and function: a) oxygenation curve is sigmoidal b) a hemoglobin molecule comprises one non-protein group (heme) and, accordingly, may transport one oxygen molecule c) the binding of oxygen occurs cooperatively d) carbon dioxide competes with oxygen for binding sites on the hemoglobin molecule a, b + a, c b, c c, d Choose characteristics of myoglobin dissociation curve: a) the curve is hyperbolic b) the curve is sigmoidal c) myoglobin has a higher affinity for oxygen than hemoglobin d) dissociation curve for myoglobin is not different from the curve for hemoglobin a, b + a, c b, c c, d The ligand binding site in the protein: a) is formed at the level of supersecondary structure b) in shape and charge is complementary to the ligand c) is a coenzyme d) is formed at the level of tertiary structure a, b a, c + b, d only d Choose the factors of protein stability in aqueous solution: a) the charge of the protein molecule b) the hydration shell c) the molecular weight of the protein d) the protein function + a, b, c a, c, d b, c, d only b Isoelectric point: a) the pH at which the net charge of the protein is neutral b) for all the proteins in the body is the same c) for negatively charged proteins is in an alkaline medium d) for negatively charged proteins is in an acidic medium a, b a, c + a, d c, d Choose the factors causing denaturation of proteins: a) boiling b) action of heavy metals salts c) action of alkaline-earth metal salts d) cooling to + 4°C + a, b a, c b, c c, d What types of bonds are destroyed in protein denaturation? a) peptide b) hydrogen c) disulfide d) ionic a, b, c a, d + b, c, d c, d Choose correct statements about the relationship between hemoglobin structure and function: a) oxygenation of one heme group increases the affinity of another group for oxygen b) oxygenation of one heme group reduces the affinity of another group for oxygen c) change of iron position relative to the plane of the porphyrin ring in heme causes a conformational change in other parts of the hemoglobin molecule d) 2,3-bisphosphoglycerate increases the affinity of hemoglobin for oxygen and inhibits O2 transfer to tissues a, b, c + a, c b, c, d c, d Choose the soluble proteins: a) collagen fibers b) albumin c) phosphoprotein d) hemoglobin a, b b, c + b, c, d only d What happens when the denaturation of proteins occurs? a) changes in non-covalent bonds b) loss of the ability to interact with the natural ligand c) changes in protein solubility d) breakdown of peptide bonds a, b + a, b, c b, c, d c, d Choose the class of enzyme that catalyzes the reaction: + + L-glutamate + NAD + Н2О ↔ iminoglutarate + NADH∙H + oxidoreductase isomerase transferase ligase Choose the class of enzyme that catalyzes the reaction: Urea + H2O → 2NH3 + CO2 ligase + hydrolase lyase oxidoreductase Dehydrogenase carries out the reaction: urea + Н2О → 2NH3 + СО2 AН2 + О2 → A + Н2О2 + AН2 + В → A + ВН2 2Н2О2 → 2Н2О + О2 Choose the correct statement about oxygenase: the transfer of hydrogen atoms from the substrate to an intermediate acceptor the transfer of hydrogen atoms from the substrate to oxygen + the inclusion of atomic or molecular oxygen into the substrate catalyzes the peptide bond breakdown with the addition of water Choose the correct statement about esterases: catalyzes the oxidation of organic compounds with molecular oxygen to form a hydroxyl group + acts on ester bonds uses NAD+ and NADP+ as the intermediate hydrogen acceptors the transfer of hydrogen atoms from the substrate to oxygen Choose the class of enzyme that catalyzes the reaction: lactate + NAD+ ↔ pyruvate + NADH∙Н+ hydrolase isomerase + oxidoreductase transferase Choose the correct statement about peptidases: accelerates reactions of non-hydrolytic decomposition of organic compounds at the bond carbon - oxygen catalyzes the oxidation of organic compounds with molecular oxygen to form a hydroxyl group + catalyzes the cleavage of peptide bonds with the addition of water uses NAD+ and NADP+ as the intermediate hydrogen acceptors Choose the correct statement about ligases: + addition of CO2 to the substrate molecule with the expenditure of ATP the transfer of hydrogen atoms from the substrate to an intermediate acceptor the inclusion of atomic or molecular oxygen into the substrate accelerates reactions of non-hydrolytic decomposition of organic compounds at the bond carbon - oxygen Find the corresponding class of enzymes to the given enzyme-catalyzed reaction: lyase oxidoreductase + transferase isomerase Find the corresponding class of enzymes to the given enzyme-catalyzed reaction: + hydrolase transferase oxidoreductase ligase Find the corresponding class of enzymes to the given enzyme-catalyzed reaction: hydrolase + transferase oxidoreductase lyase Find the corresponding class of enzymes to the given enzyme-catalyzed reaction: + lyase oxidoreductase isomerase transferase What is the optimum temperature for the action of the majority of enzymes? - 20 - 30 °C - 80 - 100 °C + 35 - 40 °C - 70 - 80 °C If the concentration of the enzyme increases and the substrate is in plenty, the rate of enzymatic reaction: + Continuously increases in proportion to the concentration of enzyme - Does not change - First increases, then it remains at the same level - First decreases and then increases The initial reason for the decline of enzyme activity at a deviation from the optimum pH is: - Changing the configuration of the enzyme - Allosteric change in the conformation of the enzyme + Changing the ionization of the enzyme functional groups - Enzyme hydrolysis of peptide bonds The maximum rate of the enzymatic reaction is achieved when: - The enzyme concentration is equal to Km + There is an excess of substrate - The enzyme substrate ratio is 1: 1 - Substrate concentration is equal to Km Michaelis-Menten constant - is: - Substrate concentration at which the enzymatic reaction rate is minimal - Ratio, reflecting the dependence of the reaction rate on the temperature + Substrate concentration at which the rate of enzymatic reaction is half maximal - Substrate concentration at which the enzymatic reaction rate is maximal Which statement about enzyme kinetics is right? + A high Km value indicates a low affinity of the enzyme for its substrate - The value of Km is dependent on the concentration of enzyme - The enzyme increases the rate of a chemical reaction by changing the reaction equilibrium constant - The maximum rate of the enzymatic reaction is observed when the formation of substrate-enzyme complex is complicated Chemical analogues of substrates can act as: - Allosteric inhibitors + Competitive inhibitors - Non-competitive inhibitors - Non-specific activators The excess of CTP inhibits the synthesis of pyrimidine nucleotides. The mechanism of the inhibition is based on: - Joining with inhibiting proteins + Allosteric regulation - Partial proteolysis - Phosphorylation of the key enzyme Regulation of oxygen binding in hemoglobin by 2,3-diphosphoglycerate - is: - Feedback regulation - Cross allosteric regulation - Connection or cleavage of regulatory proteins + Connection or elimination of low molecular weight effector The covalent modification of the enzyme is carried out by all of the following reactions, except: - Phosphorylation + Total proteolysis - Dephosphorylation - Selective proteolysis There are three sections on the graph representing the relationship between enzymatic reaction rate and substrate concentration. Which of them corresponds to a first order equation? + Segment on the chart corresponding to the directly proportional relationship - Straight portion corresponding to the saturation of the enzyme with substrate -Segment on the chart describing indirectly proportional dependence of the reaction rate on the increasing substrate concentration - There is no such section on the chart The action of the enzyme is characterized by specificity. That means: - The ability of the active site of the enzyme to bind to an allosteric regulator - The ability of the active site of the enzyme to bind to a competitive inhibitor + The ability of the active site of the enzyme to bind selectively to specific substrate(s) - The ability to accelerate chemical reaction after covalent modification of the enzyme During the enzymatic catalysis the formation of enzyme-substrate complex takes place. It includes the following processes: a) changes in the substrate conformation b) changes in 3D-structure of the enzyme c) approximation of functional groups involved in catalysis d) changes in the primary structure of the enzyme a, b + a, c b, d c, d Choose compounds that act as coenzymes: a) vitamin K b) nucleotides c) metals d) vitamin E a, b b, c + a, b, c b, d What statements correctly characterize the enzyme active site? a) the site that directly interacts with the substrate, and is involved in catalysis b) the active site occupies most of the enzyme molecule c) the active site and the substrate are complementary to each other d) the active site contains only polar amino acids a, b + a, c b, c a, d Choose the possible functions of coenzyme in enzymatic catalysis: a) is involved in binding the substrate to the enzyme b) promotes the formation of a complementary conformation of the allosteric site to the substrate c) can participate in catalysis in association with apoenzyme d) stabilizes the structure of the enzyme a, b, c b, c, d +a, c, d only c Choose the features of allosteric enzymes: a) the presence of the quaternary structure b) their activity can be regulated by low-molecular weight effectors c) catalyze the reaction proceeding in one direction d) catalyze the fastest reaction in metabolic pathway + a, b, c a, b, d b, c, d only d Choose the events that occur in case of allosteric inhibition of enzyme activity: a) the rate of enzymatic reaction reduces b) effector binds to the active site c) the conformation of allosteric site changes d) the conformation of the active site does not change a, b + a, c b, d c, d Choose the characteristics relating to the allosteric effectors: a) similar to the substrate b) their structure is different from the substrate c) their action persists when substrate concentration increases d) reduce Vmax of enzymatic reaction a, b, c b, c a, d + b, c, d Lineweaver-Burk graph: a) built in the double reciprocals of enzymatic reaction rate and substrate concentration b) allows you to accurately determine the Michaelis constant c) shows the dependence of enzyme reaction rate vs. inhibitor concentration d) shows a direct relationship between the reciprocals of the enzymatic reaction rate and substrate concentration a, b, d b, d + a, b, c c, d Selective proteolysis is used to activate the enzymes of the following processes: a) glycolysis b) coagulation c) digestion of food proteins in the gastrointestinal tract d) oxidative phosphorylation a, c + b, c a, d b, d NAD+, NADP+, FMN and FAD: a) are coenzymes of oxidoreductases b) serve as electron (and proton) acceptors in bio-oxidation reactions c) are the parts of coenzymes of transferases and hydrolases d) are coenzymes of dehydrogenases a, b, c + a, b, d b, c, d only d In vivo enzymatic processes are regulated by: a) the regulation of the substrate amount b) the regulation of the enzyme amount c) the regulation of the amount of reaction products d) covalent binding the effector to the allosteric center + a, b, c a, c, d b, c c, d What are the properties of competitive inhibitors? a) similar to the substrate b) bind to an allosteric site of the enzyme c) bind to the active site d) their action persists when the substrate concentration increases a, b, c b, c, d + a, c b, d Isozymes: a) have different primary structure b) catalyze different reactions c) have the same primary structure d) differ in physical and chemical properties a, b, c b, d a, c, d + a, d Which characteristics of lactate dehydrogenase are correct? a) has a quaternary structure b) has 4 isoenzyme forms c) catalyzes reaction of reversible conversion of pyruvate to lactate d) belongs to a class of oxidoreductases a, c b, d + a, c, d b, c, d The use of enzymes as drugs is limited by: a) short duration of action b) high specificity c) low stability d) difficulty in obtaining highly purified preparations a, b a, c + a, c, d b, c, d The rate of enzyme leakage from the cell into the blood is influenced on by: a) the size of enzyme molecules b) the presence of enzyme activators c) intracellular localization of enzymes d) enzyme life-time a, b + a, c b, c c, d Choose the advantages of the immobilized enzymes compared to the non- immobilized: a) reusability b) increased stability c) the high antigenicity d) possible targeting (directional transport) a, b b, c + a, b, d b, c, d Urine diastase - is: a) determination of starch or its cleavage products in urine b) the diagnostic test which is used for the detection of pancreatic diseases c) amylase activity in urine d) activity of lipolytic enzymes in urine a, b + b, c a, d c, d Choose the enzymes that are used in treatment of septic (purulent) wounds: a) trypsin b) alkaline phosphatase c) deoxyribonuclease d) amylase a, b + a, c b, d c, d The doctor ignored the patients’ analysis, which showed a 10-fold diastase increase. The patient is at risk of pancreas autolysis due to the activation of: a) pepsin b) trypsin c) nuclease d) phospholipase A2 a, b a, c + b, c, d only d Indicator enzymes - are: a) enzymes, whose increased activity in plasma indicates the presence of pathology in internal organs and tissues b) enzymes whose activity is increased in the blood plasma due to release of enzymes from the damaged cells c) the enzymes whose activity rises in the cells of tissues and organs in the pathology d) the enzymes that disappear from the plasma in heart and liver diseases + a, b a, c b, c b, d Contrycal, trasilol, gordox are used in medical practice... a) for inhibiting proteolytic enzymes in the blood plasma b) to facilitate the formation and evacuation of mucus in the airways c) to facilitate the digestion of food proteins d) for treatment of pancreatic necrosis, as they inhibit the activity of enzymes that enter the blood from the damaged cells of the pancreas a, b + a, d b, c c, d Choose the possible causes of hyperenzymemia: a) damaged tissue (cell necrosis, inflammation) b) increased number of cells producing the enzyme (tumor) c) obstruction of ducts through which enzymes are excreted into the cavities d) enzymes enter the blood from the gastrointestinal tract together with food digestion products + a, b, c b, c c, d only d Hypoenzymemia may be due to: a) damaged tissue (cell necrosis, inflammation) b) decreased synthesis of enzymes resulted from the development of pathological process c) congenital enzyme deficiency d) presence of inhibitors of the enzyme activity a, b a, d + b, c, d c, d Phosphofructokinase catalyzes the reaction: +Fructose-6-phosphate + ADP → Fructose-1,6-diphosphate + ADP -3-Phosphoglycerate ↔ 2-Phosphoglycerate -Phosphoenolpyruvate + ADP → Pyruvate + ATP -Glyceraldehyde 3-phosphate ↔ Dihydroxyacetone phosphate Choose the way of using the glycolytic NADH.Н+ under anaerobic conditions: -It is the source of electrons and H+ for the respiratory chain -It helps to reduce lactate to pyruvate +It is oxidized in the reduction of pyruvate to lactate -It is used in substrate-level phosphorylation Choose the reaction of aerobic glycolysis, which is associated with oxidative phosphorylation: -Fructose-6-phosphate + ATP → Fructose-1,6-diphosphate + ADP +Glyceraldehyde 3-phosphate+ NAD+ + Н3РО4 ↔ 1,3-Diphosphoglycerate + NADН.Н+ -Phosphoenolpyruvate + ADP → Pyruvate + ATP -1,3-Diphosphoglycerate + ADP ↔ 3-Phosphoglycerate + ATP All the following enzymes are glycolytic, except: -Lactate dehydrogenase +Pyruvate decarboxylase -Phosphofructokinase -Phosphoglycerate kinase During anaerobic glycolysis ATP is synthesized by the mechanism of: -Oxidative phosphorylation +Substrate-level phosphorylation -Photosynthetic phosphorylation -Microsomal oxidation During aerobic oxidation the glucose is broken down to: -Acetic acid -Lactic acid -Ethanol +Carbon dioxide and water Synthesis of glucose from other organic non-carbohydrate compounds is called: -Glycolysis -Glycogenolysis +Gluconeogenesis -Glygogenesis The following statements describe glycogenesis, except: -Stores glucose in the cell -During branching of glycogenα-1,6-glycosidic bonds are formed -Glycogen synthase catalyses the formation of α-1,4-glycosidic linkages +The inclusion of 1 mole of glucose into glycogen requires 6 moles of high-energy compounds The following statements describe glycogenolysis, except: -Glycogen phosphorylase cleaves α-1,4-glycosidic bonds -Is stimulated by glucagon in the liver -Is stimulated by epinephrine in muscles +Is stimulated by hyperglycemia The absence of one enzyme results in formation of different products during glycogen phosphorolysis in liver and muscles. Choose this enzyme from the following: -Hexokinase -Glucokinase -Glycogen phosphorylase +Glucose-6-phosphatase Choose the activator of glycogen synthase: -ATP +Glucose-6-phosphate -Galactose -cAMP Activation of glycogen phosphorylase occurs via: -Dephosphorylation +Phosphorylation -Selective proteolysis -Glycosylation Choose the enzymes involved in the digestion of starch: a) salivary α-amylase b) pancreatic α-amylase c) gastric α-amylase d) maltase + a, b, d b, c, d a, b c, d Choose the correct answers about parietal digestion of carbohydrates: a) lactose is broken down to glucose and galactose b) maltose cleavage is catalyzed by maltase c) enzymes are located on the brush border of enterocytes d) glucose is phosphorylated by the action of hexokinase a, b + a, b, c a, c, d b, c, d Choose the correct answers about lactase deficiency: a) accompanied by diarrhea, bloating and intestinal cramps b) is associated with the consumption of lactulose c) occurs in congenital deficiency of lactase d) can be caused by reduction of lactase activity due to intestinal diseases a, c a, b, c + a, c, d b, c, d Choose the glucose transporting proteins in enterocytes: a) Ca-ATPase b) Na+,К+- ATPase c) GLUT d) SGLT1 a, b b, c b, d + c, d Choose the organs whose cells have insulin-dependent glucose transporters (GLUT 4): a) intestine b) brain c) adipose tissue d) skeletal muscles a, b b, c b, d + c, d Choose the correct answers. The following sequence of reactions: Dihydroxyacetone phosphate ↔ glyceraldehyde 3-phosphate↔ 1,3- diphosphoglycerate ↔ 3-phosphoglycerate ↔2-phosphoglycerate ↔ phosphoenolpyruvate: a) may be a step of aerobic glucose oxidation b) occurs during gluconeogenesis c) involves irreversible reactions d) includes the reaction of substrate-level phosphorylation a, b, c + a, b, d a, c, d b, c, d Choose the possible ways of pyruvate conversion in the cell: a) carboxylation with oxaloacetate formation b) oxidative decarboxylation with acetyl-CoA formation c) condensation with ascorbate formation d) reduction with lactate formation a, b, c + a, b, d a, c, d b, c, d Choose indigestible polysaccharides: a) cellulose b) pectins c) lactulose d) glycogen + a, b a, c a, c, d b, c, d Choose the stages of aerobic glucose oxidation till the formation of end products (СО2 and Н2О) in humans: a) glycolysis b) oxidative decarboxylation of pyruvate c) tricarboxylic acid cycle d) decarboxylation of pyruvate to acetaldehyde a, b b, c + a, b, c b, c, d Choose the enzymes, which are involved in parietal digestion of disaccharides in intestine: a) maltase b) sucrase c) lactase d) amylase + a, b, c b, c, d a, b b, c The enzymes involved in carbohydrate digestion in humans are produced: a) in the oral cavity b) in pancreas c) in enterocytes d) in stomach a, b + a, b, c a, c, d b, c, d Choose the right combinations "enzyme, the source of enzyme": a) glucokinase, liver b) hexokinase, muscles c) glucokinase, brain d) glucose-6-phosphatase, muscles + a, b a, c b, d c, d Choose the main functions of pentose phosphate pathway: a) generation of NADPH.Н+ in cytosol b) to supply ribose-5-phosphate for tissues c) to supply the substrates for gluconeogenesis d) to supply acetyl-CoA for fatty acid and steroid biosynthesis + a, b b, d a, b, c b, c, d Choose the enzymes of pentose phosphate cycle that catalyze reduction of NADP+: a) alcohol dehydrogenase b) glyceraldehyde-3-phosphate dehydrogenase c) glucose-6-phosphate dehydrogenase d) 6-phosphogluconate dehydrogenase a, b, c b, c, d a, c + c, d Choose the correct characteristics of glucose-6-phosphate dehydrogenase: a) regulatory enzyme of pentose phosphate cycle b) the defect in the enzyme structure provides protection against tropical malaria c) deficiency of this enzyme in red blood cells leads to hemolytic anemia d) catalyzes reduction of NAD+ + a, b, c b, c, d a, c c, d Choose the correct characteristics of transketolase: a) the enzyme of non oxidative phase in pentose phosphate cycle b) catalyzes reversible reaction c) catalyzes 3-carbon unit transfer reaction d) uses thiamine pyrophosphate as a coenzyme + a, b, d b, c, d a, d b, c Choose the biological role of non oxidative phase of pentose phosphate pathway: a) to provide ribose-5-phosphate b) utilization of the ribose-5-phosphate excess c) reduction of NAD+ d) reduction of NADP+ a, c a, b, d b, c, d + a, b Choose the functions of uronic acid pathway in humans: a) provides UDP-glucuronic acid for detoxification of xenobiotics b) provides UDP-glucuronic acid for biosynthesis of glycosaminoglycans c) ascorbic acid synthesis d) entry of dietary xylitol into metabolism + a, b, d b, c, d b, d c, d Choose the cells where glucose can be utilized in uronic acid pathway: a) hepatocytes b) enterocytes c) erythrocytes d) fibroblasts a, c + a, d a, b, c b, c, d Choose the tests which can be carried out to assess the state of carbohydrate metabolism: a) determination of pancreatic lipase activity b) determination of blood glucose level c) determination of urine glucose content d) glucose tolerance test a, c b, d a, b, c + b, c, d Choose the correct statements about effect of insulin on carbohydrate metabolism: a) stimulates inclusion of GLUT 4 in cell membrane of myocytes and adipocytes b) stimulates glycolysis c) stimulates gluconeogenesis d) stimulates glycogenesis a, c b, d + a, b, d b, c, d The following hormones have hyperglycemic effect: a) epinephrine b) glucagon c) thyroxin d) insulin a, c + a, b, c a, c, d b, c, d Choose the causes of hypoglycemia: a) hyperinsulinism b) genetic defect of glucose-6-phosphatase (Von Gierke’s disease) c) stress d) excess of cortisol + a, b a, c b, c c, d Choose physiological blood glucose concentrations: a) 3,3 – 5,5 g/l b) 3,9 – 6,1 mmol/l c) 70 - 110 mg/100 ml d) 5,5 – 10 mmol/l e)1,7 – 3,3 mmol/l a, b, d a, д + b, c c, d, e Insert the missing components in the reaction: dihydroxyacetonephosphate + ……. ↔ fructose-1,6-bisphosphate ATP + glyceraldehyde-3-phosphate phosphoenolpyruvate 3-phosphoglycerate Choose the appropriate enzyme for the reaction of pentose phosphate pathway: glucose-6-phosphate + NADP+ → 6-phosphogluconolactone + NADPН.Н+ + glucose-6-phosphate dehydrogenase lactonase 6-phosphogluconate dehydrogenase glucose-6-phosphatase How many moles of ATP can be synthesized in oxidation of 1 mole of substrate in the following process: succinate → oxaloacetate? + 4 moles 10 moles 7.5 moles 2.5 moles How many moles of ATP can be synthesized in oxidation of the amino acid (asparagine → oxaloacetate) to the end products (СО2, Н2О) in mitochondria? 27.5 moles 22.5 moles + 20 moles 10 moles Choose the reactions of TCA cycle accompanied by hydrogen elimination using flavin-dependent dehydrogenase: isocitrate → α-ketoglutarate + succinate → fumarate fumarate → malate malate → oxaloacetate Choose the appropriate enzyme for the reaction of glycolysis: fructose-6-phosphate→ glyceraldehyde-3-phosphate + dihydroxyacetone phosphate + aldolase A phosphohexoisomerase phosphoglycerate kinase phosphofructokinase Choose the appropriate enzyme for the key reaction of gluconeogenesis: oxaloacetate + GTP → phosphoenolpyruvate + СО2 + GDP + Pi pyruvate carboxylase + phosphoenolpyruvate carboxykinase glucose-6-phosphatase pyruvate kinase How many moles of ATP can be synthesized in oxidation of 1 mole of substrate in the following process: glucose → 2 lactate? + 2 moles 2.5 moles 3.5 moles 1.5 moles How many moles of ATP can be synthesized in oxidation of 1 mole of substrate in the following process: glyceraldehyde-3-phosphate → lactate? + 2 moles 4-5 moles 3 moles 1 mole How many moles of ATP can be synthesized in oxidation of 1 mole of substrate in the following process: glucose → 2 phosphoenolpyruvate? + 0 moles 1 mole 2 moles 3 moles Choose the reaction of pentose phosphate pathway that is accompanied by dehydrogenation and decarboxylation: + 6-phosphogluconate →ribulose-5-phosphate glucose-6-phosphate → 6-phosphogluconolactone ribose-5-phosphate + xylulose-5-phosphate → sedoheptulose-7-phosphate + glyceraldehyde-3-phosphate glucose → glucose-6-phosphate Choose the reactions of glycolysis that are accompanied by isomerization: glyceraldehyde-3-phosphate→1,3-bisphosphoglycerate phosphoenolpyruvate → pyruvate + glucose-6-phosphate→ fructose-6-phosphate pyruvate → lactate Choose the correct sequence of the enzymes of pyruvate dehydrogenase complex: a) dihydrolipoyl dehydrogenase b) dihydrolipoyl transacetylase c) pyruvate decarboxylase a→b→c b→a→c +c→b→a c→a→b Choose the correct sequence of the coenzymes of multienzyme complex performing oxidative decarboxylation of pyruvate: a) TPP b) NAD+ c) FAD a→b→c b→a→c +a→c→b c→a→b Choose the correct sequence of citrate cycle stages: a) substrate-level phosphorylation at a level of succinyl-CoA b) succinate dehydrogenation c) malate dehydrogenation d) fumarate hydratation +a→b→d→c a→c→b→d b→d→a→c c→a→b→d Choose the correct sequence of dehydrogenase reactions in Krebs cycle: a) conversion of succinate to fumarate b) α-ketoglutarate dehydrogenation c) isocitrate dehydrogenation a→b→c a→c→b b→c→a +c→b→a Choose the correct sequence of steps in catabolism of nutrients: a) citric acid cycle b) hydrolysis of proteins, fats, carbohydrates in the gastrointestinal tract c) oxidative decarboxylation of pyruvate a→b→c b→a→c +b→c→a c→b→a Choose the correct sequence of steps in oxidative phase of glycolysis: a) 1,3-diphosphoglycerate +ADP→ 3-phosphoglycerate + ATP b) 3-phosphoglycerate→ 2-phosphoglycerate c) glyceraldehyde-3-phosphate → 1,3-diphosphoglycerate d) 2-phosphoglycerate→phosphoenolpyruvate a→b→d→c +c→a→b→d a→c→d→b a→c→b→d Glucose reduction pathway intensifies in Diabetes mellitus. Choose the correct sequence of participants of this pathway: a) glucose b) sorbitol c) fructose +a→b→c a→c→b c→b→a c→a→b Choose the correct sequence of Krebs’ cycle reactions: a) α-ketoglutarate → succinyl-CоA b) acetyl-CоA + oxaloacetate → citrate + CоA-SH c) isocitrate → α-ketoglutarate d) citrate → isocitrate a→b→c→d b→c→a→d +b→d→c→a d→b→a→c Choose the correct sequence of intermediates in gluconeogenesis starting from alanine: a) pyruvate b) alanine c) oxaloacetate d) phosphoenolpyruvate a→b→c→d +b→a→c→d b→d→c→a b→c→d→a Choose the correct sequence of enzymes participating in lactate oxidation to СО2 and Н2О: a) lactate dehydrogenase b) pyruvate dehydrogenase c) isocitrate dehydrogenase d) α-ketoglutarate dehydrogenase +a→b→c→d a→c→b→d a→d→c→b b→a→c→d Choose the correct sequence of Krebs’ cycle enzymes performing isocitrate oxidation: a) isocitrate dehydrogenase b) α-ketoglutarate dehydrogenase c) succinyl-CоAsynthetase d) succinate dehydrogenase +a→b→c→d a→c→b→d a→d→c→b b→a→c→d Choose the correct sequence of gluconeogenesis’ reactions, which require energy consumption (AТP or GТP): a) pyruvate → oxaloacetate b) oxaloacetate → phosphoenolpyruvate c) 3-phosphoglycerate → 1,3-bisphosphoglycerate +a→b→c a→c→b c→b→a c→a→b Choose regulatory enzymes of Krebs cycle: a) isocitrate dehydrogenase b) fumarase c) citrate synthase d) malate dehydrogenase a, b + a, c a, b, d b, c, d Which reactions of Krebs cycle are associated with complex I of respiratory chain? a) isocitrate→ α-ketoglutarate b) α-ketoglutarate → succinyl-CoA c) succinate → fumarate d) malate → oxaloacetate a, b a, b, c + a, b, d only c Which enzymes of Krebs cycle use vitamin PP as a coenzyme? a) isocitrate dehydrogenase b) succinate dehydrogenase c) malate dehydrogenase d) α-ketoglutarate dehydrogenase a, c b, d + a, c, d b, c, d Choose the participants of the respiratory chain, which can transfer both electrons and protons: a) ubiquinone b) cytochromes a and a3 c) FAD d) FMN a, b a, b, c + a, c, d b, c, d Choose the participants of electron transport from NAD-dependent substrates to oxygen: a) FAD b) FMN c) cytochromes d) ubiquinone a, b c, d a, b, c + b, c, d Choose the correct statements about ATP-synthase: a) enzyme complex V of the inner mitochondrial membrane b) is inhibited by oligomycin c) has a proton channel d) is inhibited by rotenone a, b + a, b, c a, c, d c, d Choose the correct postulates of Mitchells’ chemiosmotic theory: a) the inner mitochondrial membrane is impermeable to protons b) protons pumped during electron transport into the matrix of mitochondria create a pH gradient across the membrane c) the position of the carrier in the electron transport chain depends on its redox potential d) electrochemical potential generated during electron transport is a driving force of ADP phosphorylation a, b, c b, c, d a, b + a, d Which changes take place in the uncoupling of tissue respiration and oxidative phosphorylation in mitochondria? a) the rate of the respiration and phosphorylation reduces b) the respiration is stimulated and phosphorylation is decreased c) the rate of the respiration and phosphorylation increases d) electrochemical potential across the inner mitochondrial membrane decreases only d a, d + b, d c, d Choose the non-protein components of complex I of respiratory chain (NADH- ubiquinone oxidoreductase): a) FMN b) FeS c) FAD d) NADP+ + a, b b, c, d a, c a, b, d Complex III of respiratory chain (ubiquinol-cytochrome с oxidoreductase) includes: a) cytochrome a b) FeS c) cytochrome b d) cytochrome c1 a, b, c a, c, d a, b, d + b, c, d Choose the complexes of the respiratory chain, which are involved in the generation of an electrochemical potential across the inner mitochondrial membrane: a) succinate-ubiquinone oxidoreductase b) NADH-ubiquinone oxidoreductase c) cytochrome с-oxidase d) ubiquinol-cytochrome с oxidoreductase a, b, c a, c, d a, b, d + b, c, d Choose the correct statements about complex IV of respiratory chain (cytochrome с oxidase): a) contains atoms of iron and copper b) provides the reaction of ADP phosphorylation c) provides the complete four-electron reduction of oxygen with water formation d) pumps 10 protons from the matrix into the intermembrane space a, b b, d + a, c c, d There are four levels of interrelations between catabolism and anabolism – substrate level, energy level, regulation level and: -uric acid level -urea level +reduced coenzyme level -creatine level Choose the final product formed in stage II of catabolism: -Isocitrate -Succinyl-CoA -Oxaloacetate +Acetyl-CoA Most of the main metabolic pathways are usually either catabolic or anabolic. Which pathway from the following is amphibolic? -Glycolysis -β-Oxidation of fatty acids +Citric acid cycle -Gluconeogenesis What are the chemical differences between NAD+ and NADP+? +NADP+ has additional phosphate on the pentose linked to adenine -NAD+ contains more nicotinic acid than nicotinamide -NADP+ has additional phosphate on the pentose linked to nicotinamide -They contain different nitrogenous bases Which carrier of respiratory chain is inhibited by malonate? -NADН-ubiquinone oxidoreductase +Succinate-ubiquinone oxidoreductase -Ubiquinol-cytochrome с oxidoreductase -Cytochrome с oxidase Which of these functions is impaired in mitochondria after treatment with substances that affect the permeability of membranes? +Coupling of oxidation and phosphorylation -Electron transport via respiratory chain -Dehydrogenation of NAD-dependent substrates -Dehydrogenation of FAD-dependent substrates Uncoupling of tissue respiration and phosphorylation occurs due to: -Decreasing the activity of Н+-ATP-synthase +Increasing the permeability of inner mitochondrial membrane to protons -Blocking of cytochrome c oxidase by cyanides -Increasing the electrochemical potential across the inner mitochondrial membrane What is the mechanism of inhibition of tissue respiration by cyanides and carbon monoxide? -Damage of inner mitochondrial membrane +Binding of iron atoms of cytochromes а and а3 -Defect of oxygen transport into mitochondrial matrix -Inhibition of ATP-synthase activity Choose the regulatory enzyme of Krebs cycle: +Isocitrate dehydrogenase -Succinyl-CоА synthetase -Succunate dehydrogenase -Aconitase Which enzyme of Krebs cycle becomes activated in a low level of ATP? +Citrate synthase -Fumarase -Aconitase -Succinyl-CоА synthetase Choose the inhibitor of regulatory enzymes of citric acid cycle: -NADPН.Н+ -NAD+ +АТP -АМP The respiratory control in mitochondria is provided by: -Lactate +АDP -АМP -Inorganic phosphate Which lipid corresponds to the following formula? a) lecithin b) phosphatidylethanolamine c) phosphatidylcholine d) phosphatidylinositol + a, c a, b b, d a, d Which lipid corresponds to the following formula? a) phosphatidylethanolamine b) phosphatidylcholine c) cephalin d) phosphatidylserine + a, c a, b b, d a, d Lipids - natural organic compounds, that are: a) soluble in water b) soluble in nonpolar solvents c) soluble in acids d) esters of fatty acids a, b, c a, c + b, d a, d Sphingomyelin consists of: a) sphingosine, 1 fatty acid residue, phosphoric acid residue, and choline b) sphingosine, two residues of fatty acids, phosphoric acid residue, and choline c) glycerol, 2 fatty acid residues, a phosphoric acid residue, and choline d) ceramide, phosphoric acid residue, and choline a, c a, b b, d + a, d Choose the characteristics common to triacylglycerols, glycerophospholipids and cerebrosides: a) they contain an ester or amide linkage with a fatty acid b) they don’t contain a glycerol residue c) they contain sphingosine d) they can be subjected to alkaline hydrolysis a, c a, b b, d + a, d Ceramide is a precursor of: a) glycerophospholipids b) gangliosides c) cerebrosides d) waxes b, d a, b + b, c a, d Choose the correct answers. Gangliosides: a) are hydrophilic compounds b) are amphipathic compounds c) contain ceramide and monosaccharide d) contain ceramide and oligosaccharide a, d + b, d b, c, d c, d Choose the constituents of phosphatidylinositol: a) phosphoric acid b) glycerol c) one fatty acid residue d) two fatty acid residues a, b, c a, c b, c, d + a, b, d Choose glycolipids: a) galactosylceramide b) ganglioside Gм1 c) sphingomyelin d) cholesterol a, b, c + a, b b, c, d a, b, d Triacylglycerol and phosphatidylserine were subjected to hydrolysis. Choose the resulting products, which are specific for phosphatidylserine? a) phosphoric acid b) serine c) glycerol d) sphingosine a, b, c + a, b b, c, d a, b, d Phosphatidylcholine consists of: a) sphingosine, 1 fatty acid residue, phosphoric acid residue, and choline b) glycerol, 2 fatty acid residues, a phosphoric acid residue, and choline c) glycerol, one unsaturated fatty acid residue, phosphoric acid, and choline d) phosphatidic acid and choline a, b a, b, c c, d + b, d Choose common products, which are formed by alkaline hydrolysis of phosphatidylcholine and sphingomyelin: a) salts of fatty acids b) phosphoric acid c) glycerol d) choline a, b, c a, b b, c, d + a, b, d All statements regarding cholesterol are correct, except: -Sex hormones, glucocorticoids and mineralocorticoids are produced from cholesterol -Bile acids are the end products of cholesterol metabolism -Vitamin D is synthesized from cholesterol +Cholesterol is a precursor for vitamin A Choose the correct statement regarding cholesterol: -The substrate for the synthesis of triacylglycerols -The substrate for the synthesis of phospholipids +The substrate for the synthesis of glucocorticoids -Undergoes cleavage under the action of pancreatic lipase Specify to which group of lipids belongs this substance: -Simple lipids +Cholesterol esters -Lanosterol -Cholesterol Which of the following compounds is the major dietary fat? - - - + Waxes are: -Acylglycerols +Esters of an alcohol and fatty acid -Steroids -Glycolipids Simple lipids include: - Phospholipids - Glycolipids +Triacylglycerols -Sulfolipids Palmitic acid – this is…: -The carboxylic acid containing 18 carbon atoms -The fatty acid containing 16 carbon atoms and 1 double bond +Saturated fatty acid containing 16 carbon atoms -Unsaturated fatty acid with no double bonds between carbon atoms Cholesterol according to the classification of lipids belongs to: -Saponifiable simple lipids -Saponifiable complex lipids +Unsaponifiable lipids - Neutral fats Common structural components for mono-, di- and triacylglycerols are: -Residues of orthophosphoric acid and fatty acids -Residues of glycerol and monosaccharides (glucose and galactose) +Residues of trihydric alcohol glycerol and fatty acids -Residues of trihydric alcohol glycerol, phosphoric acid and fatty acids Choose the amphipathic lipids: -Phospholipids and triacylglycerol +Phospholipids and free cholesterol -Phospholipids and esterified cholesterol -Waxes and glycolipids Molecules of phospholipids are composed of hydrophobic and hydrophilic portions. Select a hydrophobic region: -Phosphoric acid residue -Choline residue -Ethanolamine residue +The fatty acid residues attached to the alcohol Triacylglycerols are completely insoluble in water, since: +They do not include groups capable of dissociation or having polarity -They include monosaccharides -Their main component is the residue of phosphoric acid -Their chemical structure includes choline molecule whose nitrogen has a positive charge The primary bile acids are formed in: -Intestine -Skin +Liver -Adrenals Secondary bile acids are formed in: +Intestine -Skin -Liver -Adrenals What amount of bile acids is absorbed daily in the lower part of small intestine in adult? -12 g -0,5 g -95 mg +29,5 g Which of the following compounds is produced (along with the fatty acids) by lipase? - - + - - OОC-CH2-CO-SCoA Which of the following compounds is a substrate of pancreatic lipase? - - + - Phosphatidylcholine was hydrolyzed by phospholipase A2. Choose the products of this reaction: +Fatty acid + 1-acyl lysophosphatidylcholine -Fatty acid + 2-acyl lysophosphatidylcholine -2 Fatty acid + glycero-3-phosphocholine -Fatty Acid + glycerol-3-phosphate + choline Some snake venoms contain phospholipase A2that catalyzes the formation of lysophospholipids. Specify the site of its action on the scheme: -1 +2 -3 -4 Select the correct statement from the following: - First lipase cleaves hydroxyl groups in triacylglycerols - Hydrolysis of 2-monoacylglycerols results in formation of glycerol and two higher fatty acids - Acyl-CoA dehydrogenase comprises NAD+ as a coenzyme + 2-Monoacylglycerol, glycerol, and fatty acids are the final products of triacylglycerol digestion under the action of pancreatic lipase In phosphatidylcholine resynthesis1,2-diacylglycerol reacts with: -UDP-choline + CDP-choline - ADP-choline - GDP-choline Fatty acids are activated in the reaction with: +CoA-SH -Acetyl-CoA -Acyl-CoA -ACP-SH Specify the name of an enzyme catalyzing the following reaction: Cholesterol + R-CO-SKoA → Cholesterol ester + HS-CoA + Acyl CoA cholesterol acyltransferase - Acyl CoA cholesterol ligase - Acyl-CoA cholesterol acylsynthetase - Acyl-CoA cholesterol dehydrogenase Micelle formation is one of three stages of lipid digestion in gastrointestinal tract. It is: - Splitting triacylglycerol molecules under the influence of gastric lipase + Formation of the smallest particles from bile acids and products of the fat enzymatic hydrolysis that undergo absorption -Breaking down fat droplets into smaller particles under the influence of intestinal motility, bubbles of carbon dioxide, and bile acids - Formation of lipid conglomerates due to intestinal motility Choose a correct sequence of intermediates for the metabolic pathway in enterocytes: a) b) c) c→a→b +a→c→b b→a→c a→b→c Arrange sequentially the intermediates of fatty acid β-oxidation: a) CH3(CH2)4-CH(OH)-CH2-CO-SCoA b) CH3(CH2)4-CO-SCoA c) CH3(CH2)4-CO-CH2-CO-SCоA +a→c→b c→a→b b→a→c a→b→c  Arrange sequentially the reactions of fatty acid β-oxidation: a) dehydrogenation of acyl-CoA b) hydration c) dehydrogenation of β-hydroxyacyl-CoA +a→b→c a→c→b b→a→c c→a→b Select the correct sequence of vitamins whose coenzyme forms are involved in the reactions of fatty acid β-oxidation in the mitochondrial matrix: a) vitamin B2 b) vitamin PP c) pantothenic acid during the formation of acetyl-CoA +a→b→c a→c→b b→c→a b→a→c Select a correct sequence of intermediates of phospholipid synthesis in the liver: a) glycerol b) phosphatidic acid c) glycerol 3-phosphate d) phosphatidylcholine (lecithin) c→a→d→b a→d→b→c +a→c→b→d b→a→c→d Specify the correct sequence of intermediates for triacylglycerol synthesis in adipocytes: a) phosphatidic acid b) dihydroxyacetone phosphate c) 1-acyl-glycerol 3-phosphate d) glycerol-3-phosphate c→a→d→b b→d→a→c a→c→b→d +b→d→c→a  Specify the correct sequence of metabolites involved in the synthesis of fatty acids: a) hydroxybutyryl-ACP b) malonyl-ACP c) crotonyl-ACP d) acetoacetyl-ACP c→a→d→b +b→d→a→c a→c→b→d b→d→c→a Specify the correct sequence of enzymes involved in synthesis of fatty acids: a) ketoacyl synthase b) ketoacyl reductase c) hydroxyacyl dehydratase d) acetyl-CoA carboxylase c→a→d→b +d→a→b→c a→c→b→d d→b→c→a Specify the correct sequence of enzymes involved in the β-oxidation of fatty acids with odd number of carbon atoms: a) acyl-CoA dehydrogenase b) hydroxyacyl CoA dehydrogenase c) thiolase d) propionyl CoA carboxylase a→c→d→b d→a→b→c +a→b→c→d d→b→c→a Select the correct sequence of vitamins whose coenzyme forms are involved in the reactions of β-oxidation of fatty acids with odd number of carbon atoms: a) vitamin B2 b) vitamin РР c) biotin d) vitamin B12 a→c→d→b d→a→b→c +a→b→c→d a→c→b→d Choose the correct sequence of intermediates in cholesterol synthesis: a) squalene b) β-hydroxymethylglutaryl-CoA (HMG-CoA) c) mevalonic acid d) isoprene unit +b→c→d→a d→a→b→c b→a→c→d a→c→b→d Specify the correct sequence of intermediates in synthesis of ketone bodies in the liver: a) acetoacetate b) acetyl-CoA c) β-hydroxymethylglutaryl-CoA (HMG-CoA) d) acetoacetyl-CoA b→c→d→a d→a→b→c +b→d→c→a a→c→b→d Which enzyme regulates the flow of substrates in mitochondria for β- oxidation? - Acetyl-CoA carboxylase - Lipoprotein lipase - Hormone-sensitive triacylglycerol lipase +Acyl-CoA carnitine acyltransferase Which stage of β-oxidation involves the activation of fatty acids and their penetration into mitochondria from cytoplasm? - Phosphorylation of free fatty acids with ATP +Transferring fatty acid residue to carnitine - Transferring fatty acid residue from HS-CoA to creatine - Transferring fatty acid residue to mitochondrial ACP-SH Solve the problem and choose the correct answer. Complete β-oxidation of saturated fatty acid containing 18 C leads to the formation of (... ) ATP; while the energy balance will be (. ) ATP: -128, 147 +122, 120 -135, 134 -90, 89 The energy balance of complete β-oxidation of myristic acid (C 14) to CO2 and H2O is equal to: -110 ATP -94 ATP +92 ATP -70 ATP The cause of Refsum disease is: - Impaired conversion of margarine acid into pristanic acid + Congenital deficiency of receptors in peroxisomes to phytanate hydroxylase - Impaired omega-oxidation of phytanic acid - Impaired β-oxidation of dicarboxylic fatty acids ω-Oxidation of fatty acids occurs in: - Mitochondria + Endoplasmic reticulum - Ribosomes - Liposomes During α-oxidation the fatty acid: + Is shortened by 1 carbon atom - Is extended by 2 carbon atoms - Is extended by 1 carbon atom - Is shortened by 2 carbons During ω-oxidation the fatty acid chain is: - Shortened by 1 carbon atom in the mitochondria - Extended by two carbon atoms in ER + Oxidized into dicarboxylic acid in ER - Cleaved to acetyl-CoA in mitochondria What metabolic process is depicted? - β-Oxidation of fatty acids - ω-Oxidation of fatty acids - Synthesis of ketone bodies + α-Oxidation of fatty acids Which vitamin is necessary as a coenzyme for dehydrogenation of hydroxyacyl-CoA in β-oxidation of fatty acids? - Vitamin H + Vitamin PP - Vitamin B6 - Pantothenic acid The oxidation of branched and dicarboxylic fatty acids takes place in: + Peroxisomes - Mitochondria - Lysosomes - Ribosomes In what cell compartment the elongation of palmitic acid (C16) occurs? - Peroxisomes + Mitochondria - Lysosomes - Ribosomes Choose the correct statements regarding the features of short-chain fatty acid metabolism (less than 12carbon atoms): a) in order to penetrate into the mitochondria for β-oxidation they do not need a special transport system b) triacylglycerols containing such fatty acids are hydrolyzed by pancreatic lipase c) may be deposited in adipose tissue d) taken with food, increase the concentration of ketone bodies in blood + a, b, c a, b b, c, d a, b, d Choose the intermediates formed in β-oxidation of “odd-chain” fatty acids: a) succinyl-CoA b) propionyl-CoA c) methylmalonyl-CoA d) β-hydroxybutyrate + a, b, c a, b b, c, d a, b, d Ketone bodies include: a) acetoacetate b) α-hydroxybutyrate c) β-hydroxybutyrate d) acetone a, b, c + a, c, d b, c a, b, d Choose the correct answers, where the name of the enzyme corresponds to the product of reaction catalyzed by this enzyme: a) 3-hydroxy-3-methylglutaryl-CoA lyase, acetoacetate b) 3-hydroxy-3-methylglutaryl-CoA reductase, acetoacetate c) 3-hydroxy-3-methylglutaryl-CoA lyase, mevalonate d) 3-hydroxy-3-methylglutaryl-CoA reductase, mevalonate + a, d a, b b, c a, b, d Choose the correct answers regarding the fate of fatty acids released from adipose tissue during fasting: a) some of them are converted into 3-hydroxybutyrate in the liver b) some of them are converted into acetoacetate in the liver c) some of them are oxidized in neural tissue to provide energy to the brain d) some of them are oxidized to provide energy to the liver a, b, c a, c, d b, c + a, b, d Choose the common metabolites used in syntheses of cholesterol and ketone bodies: a) 3-hydroxy-3-methylglutaryl-CoA b) acetoacetyl-CoA c) acetyl-CoA d) mevalonic acid + a, b, c a, c, d b, c a, b, d Choose the enzymes involved in the metabolism of propionyl-CoA that is produced in β-oxidation of fatty acids with an odd number of carbons: a) propionyl-CoA carboxylase b) methylmalonyl-CoA mutase c) succinyl-CoA synthetase d) lactate dehydrogenase + a, b, c a, c, d b, c a, b, d What tissues use ketone bodies for energy supply? a) skeletal muscle b) kidney c) myocardium d) red blood cells + a, b, c a, c, d b, c a, b, d Specify the correct statements regarding the formation of ketone bodies: a) ketone bodies are formed in muscle tissue b) ketone bodies are synthesized from acetyl-CoA c) acetone is a product of acetoacetate decarboxylation d) ketone bodies are synthesized from cholesterol a, b, c a, c, d + b, c a, b, d In diabetes, ketosis could develop due to the following reasons: a) oxaloacetate deficiency and decreased utilization of acetyl-CoA in Krebs cycle b) reduced insulin concentration and raised glucagon level in blood c) increased concentration of insulin and decreased glucagon level in blood d) reduced rate of fatty acid synthesis because of NADPH.H+ lacking a, b a, c, d b, c + a, b, d For ketone bodies utilization the following conditions are required: a) presence of mitochondria in cells b) sufficient level of oxaloacetate in cells to ensure the functioning Krebs cycle c) formation of triacylglycerols in adipocytes d) synthesis of higher fatty acids in the liver + a, b a, c, d b, c a, b, d Choose the correct statements regarding the ketone bodies: a) synthesis of ketone bodies increases in diabetes and fasting b) ketosis develops when “insulin/glucagon” ratio in blood decreases c) ketone bodies serve as a source of energy in the liver d) erythrocytes use ketone bodies as an energy source + a, b c, d b, c a, b, d Liberation of arachidonic acid from membrane phospholipids catalyzed by phospholipase A2isinhibited by: - Aspirin - Linolenic acid + Glucocorticoids - Thrombin Anti-inflammatory activity of aspirin is based on inhibition of: + Cyclooxygenase - Phospholipase A2 - HMG-CoA reductase - Cholesterol esterase Key enzyme in leukotriene synthesis is: + Lipoxygenase - Catalase - Cyclooxygenase - Adenilate cyclase Prostaglandins: - Induce gluconeogenesis in skeletal muscles + Regulate smooth muscle contraction - Stimulate gastric secretion - Induce β-oxidation of arachidonic acid Acetyl-CoA carboxylase catalyzes the reaction in which acetyl-CoA reacts with bicarbonate to form malonyl-CoA. Which hormone promotes activation of this enzyme? - Glucagon - Adrenaline - Corticosterone + Insulin Which enzyme catalyzes the reaction: CH3-CO-SCoA + CO2 + ATP → HOOC-CH2-CO-SCoA + ADP + Pi? - Hydroxymethylglutaryl-CoA reductase + Acetyl-CoA carboxylase - Cholesterolesterase - LCAT Choose the coenzyme that participates in reactions catalyzed by β- ketoacylreductase and enoylreductase during fatty acid synthesis: + NADPH.H+ - FADH2 - Pyridoxal phosphate - NAD+ Multi-enzyme complex involved in synthesis of fatty acids is called: - Pyruvate dehydrogenase + Acyl synthase - Replisome - Golgi complex Where are the enzymes of fatty acid synthesis localized in cell? - Mitochondria - Ribosome + Cytosol - Lysosomes The initial substrate for key reaction of fatty acid synthesis is: - Succinyl-CoA + Acetyl-CoA - Glycerol - Glucose The precursor for eicosanoid synthesis is: - Glucose + Arachidonic acid - Glycerol - Amino acids Choose the function regulated by thromboxanes: - Chemotaxis + Platelet aggregation - Gastric secretion - Oxidation of arachidonic acid Choose the intermediate of cholesterol synthesis which is the isomer of isopentenyl pyrophosphate: cholesterol farnesyl pyrophosphate + dimethylallyl pyrophosphate isopentenyl pyrophosphate Specify the number of carbon atoms corresponding to farnesyl pyrophosphate in cholesterol synthesis: 27 + 15 2 6 Choose the substrate to synthesize cholesterol in hepatocytes: HMG-CoA in mitochondria + HMG-CoA in cytosol acetoacetyl-CoA in mitochondria acetoacetate in cytosol Choose the regulator of lipid metabolism which stimulates acetyl-CoA carboxylase and HMG-CoA reductase: glucagon + insulin malonyl-CoA cortisol Glucagon is a key regulator of lipid and carbohydrate metabolism. What is the reason for its fat-mobilizing effect? leads to increased glucagon secretion from α-cells of pancreas is caused by increase of cAMP level in hepatocytes + occurs due to the increased activity of hormone-sensitive lipase in adipocytes is caused by increase of cGMP level in hepatocytes Insulin is an important regulator of lipid metabolism. What is the reason for its inhibitory effect on lipolysis in adipocytes? + is caused by dephosphorylation of hormone-sensitive lipase is caused by phosphorylation of hormone-sensitive lipase is due to the activation of HMG-CoA reductase is due to the increased activity of acetyl-CoA carboxylase Specify the lipoproteins on the surface of which cholesterol esters are formed: chylomicrons VLDL + HDL IDL Specify the reason for the increased synthesis and secretion of bile acids by hepatocytes: LDL cholesterol is transported into cells for subsequent metabolism and storage chylomicrons carry re-synthesized triacylglycerols from gut into bloodstream HDL transport cholesterol from cells into the liver VLDL transport cholesterol from hepatocytes into the blood Choose the correct statement for cholesterol esters: is amphipathic compound, its main transport form is LDL + is completely hydrophobic compound transported in the blood by various lipoproteins is amphipathic compound. The major source for humans is diet is completely hydrophobic compound, which cannot be synthesized in body, so its only source for humans is diet Select the effect of a low «insulin/glucagon» ratio in blood plasma: + promotes degradation of triacylglycerols, since causes stimulation of hormone- sensitive lipase decreases degradation of triacylglycerols, since causes inhibition of hormone- sensitive lipase increases the entry of glucose into adipose tissue increases the cleavage of triacylglycerols by endothelial lipoprotein lipase Which lipase hydrolyzes only exogenous triacylglycerols? hormone-sensitive lipase hepatic lipase + pancreatic lipase lipoprotein lipase What type of lipoprotein is formed in enterocytes? + chylomicrons LDL HDL VLDL Which of the following reactions is the target of medicinal remedy "Lovastatin"? - Cyclization and conversion of squalene into lanosterol - Formation of HMG-CoA + Formation of mevalonate - Condensation of two molecules of acetyl-CoA into acetoacetyl-CoA What enzyme is the target of drugs that reduce cholesterol in plasma? - Lipoprotein lipase - Hormone-sensitive lipase + 3-Hydroxy-3-methylglutaryl-CoA reductase - Palmitoyl-CoA carnitine acyltransferase The high level of what blood lipoproteins is closely associated with a reduced risk of heart disease? - VLDL - LDL + HDL - IDL LDL levels are elevated in individuals with familial hypercholesterolemia, because of: + Poorly functioning receptors for apoB-100 - Increased synthesis of VLDL - Increased synthesis of IDL - Increased synthesis of chylomicrons What could be the cause of high concentration of blood chylomicrons in fasting? - Inadequate bile flow + Lipoprotein lipase deficiency - Lack of intestinal lipases - Molecular defect of apolipoprotein D Select a protein activated by protein kinase A: - Lipoprotein lipase - Pancreatic lipase + Hormone-sensitive lipase - Colipase LCAT activator is: - Apo C-II - Apo B-100 + Apo A-I - Apo E Continue the sentence. Glycerol formed in adipocytes during hydrolysis of triacylglycerols: - Is converted into glucose in adipocytes - Turns into glycerol phosphate under the action of glycerol kinase - Is oxidized in adipocytes + Diffuses into the blood Which enzyme is involved in the metabolism of HDL? - Lipoprotein lipase - ACAT - Pancreatic lipase + LCAT The mechanism of action of choleretic drugs used in the treatment of atherosclerosis is: - Inhibiting HMG-CoA reductase - Accelerating VLDL catabolism + Decreasing return of bile acids from intestine to the liver - Oxidation of cholesterol Choose lipoproteins carrying dietary cholesterol in the bloodstream: - LDL - VLDL - HDL + Chylomicrons What lipoproteins prevent the development of atherosclerosis? - LDL - VLDL +HDL - Chylomicrons Which of the following processes are depressed after a meal? a) glucose uptake in adipose tissue b) cleavage of triacylglycerols in adipose tissue c) formation of VLDL in the liver d) gluconeogenesis a, b a, c, d b, c + b, d Which statements are true for low density lipoproteins? a) their high level indicates a high risk of coronary heart disease b) their high level indicates a low risk of coronary heart disease c) they provide cells of peripheral tissues with cholesterol d) one of their shell protein is apo B-48 a, b + a, c b, c a, b, d Which statements about high density lipoproteins (HDL) are true? a) their high level indicates a high risk of coronary heart disease b) their high level indicates a low risk of coronary heart disease c) they provide reverse cholesterol transport d) they provide cells of peripheral tissues with cholesterol a, b a, c, d + b, c a, b, d Which statements about very low-density lipoproteins (VLDL) are true? a) their high level indicates a high risk of coronary heart disease b) one of apoproteins in their composition is apo A-I c) they provide reverse cholesterol transport d) they provide cells of peripheral tissues with fatty acids a, b a, c, d b, c + a, d Which statements concerning chylomicrons are true? a) an apoprotein in their composition is apo B-48 b) they are catabolized under the influence of lipoprotein lipase in the liver c) in blood plasma, they are converted into "remnants" d) they provide cells of peripheral tissues with fatty acids a, b + a, c, d b, c a, b, d What features correspond to apolipoprotein D? a) it is a component of HDL b) it is an activator of LCAT c) it is an activator of lipoprotein lipase d) it is involved in lipid transfer between lipoproteins a, b a, c, d b, c + a, d What features correspond to apolipoprotein C-II? a) it is a component of HDL b) it is an activator of LCAT c) it moves to chylomicrons from HDL d) it is involved in lipid transfer between lipoproteins a, b + a, c b, c a, d What features correspond to apolipoprotein E? a) it interacts with receptors on the plasma membrane of hepatocytes b) it is a component of HDL c) it moves to chylomicrons from HDL d) it is involved in lipid transfer between lipoproteins + a, b, c a, c, d b, c a, d Choose proteins found in HDL, but not in LDL: a) apo B-100 b) apo A c) apo E d) apo D a, b a, c, d + b, c, d a, d Choose the factors that increase LDL concentration in human blood: a) high consumption of cholesterol b) obesity c) a diet rich in coarse fiber products d) polyunsaturated fats in the diet + a, b a, c, d b, c, d a, d Select the factors contributing to the increase of HDL cholesterol in human blood: a) female gender c) reduction in body weight b) smoking d) male gender + a, b a, c, d b, c, d a, d What factors contribute to the development of fatty liver? a) failure of VLDL formation b) decreased phospholipid synthesis in the liver c) disorder in LDL formation d) deficiency of lipotropic factors + a, b, d a, c, d b, c, d a, d Hydrolysis of the protein to peptides (only) occurs in the presence of: a) trypsin b) chymotrypsin c) carboxypeptidase d) urease + a, b a, c c, d b, d Choose the factors that activate conversion of trypsinogen to trypsin: a) enteropeptidase b) hydrochloric acid c) trypsin d) pepsin a, b + a, c c, d b, d Choose the correct statements: a) elastase is endopeptidase and cleaves the bonds formed by amino acids with small radicals (Ala, Gly, Ser) b) chymotrypsin is endopeptidase and cleaves bonds formed by carboxyl groups of aromatic amino acids c) chymotrypsin is exopeptidase and cleaves bonds formed by heterocyclic amino acids, and the linkage Glu-Leu d) pepsin is exopeptidase and cleaves bonds formed by heterocyclic amino acids, and the linkage Gly-Lys + a, b a, c c, d b, d Choose the products that can be formed in oxidative deamination of L-amino acids: a) ammonia b) FMNH2 c) NADH.H+ d) lactate a, c, d b, c, d + a, b, c a, b, d α-Ketoglutarate + NH3 + NAD(P)H.H+ ↔ Glutamate + NAD(P)+. This reaction is used in the processes of: a) oxidative deamination b) indirect deamination of amino acids c) citric acid cycle d) ornithine cycle + a, b a, c c, d b, d Choose the enzymes involved in the oxidative deamination of amino acids in human body: a) oxidases of D-amino acids b) glutamate dehydrogenase c) α-ketoglutarate dehydrogenase d) glutamine synthetase + a, b a, c c, d b, d Choose ketogenic amino acids: a) Gly b) Lys c) Leu d) Ala a, b a, c + b, c b, d Choose possible ways to use nitrogen-free products of the transamination and deamination reactions: a) the synthesis of new amino acids b) use as an energy source c) conversion to glucose d) conversion to nucleotides a, c, d b, c, d + a, b, c a, b, d Amino acids are the main substrates for gluconeogenesis in fasting. Choose the amino acid metabolites that can be used for the synthesis of glucose: a) pyruvate b) HMG-CoA c) acetoacetyl-CoA d) oxaloacetate a, b a, c + a, d b, d After a meal, amino acids are the primary energy producing substrates for hepatocytes. Choose the pathways which allow to use ALA as an energy source during this period: a) synthesis of ketone bodies b) transamination c) oxidative decarboxylation of pyruvate d) TCA cycle a, c, d a, b, d a, b, c + b, c, d Choose the correct answer. Hydrochloric acid in the stomach: a) cause denaturation of proteins b) has a bactericidal effect c) stimulates lipase d) cause activation of pepsinogen + a, b, d b, c, d a, b, c a, c, d Choose exopeptidases: a) carboxypeptidases A and B b) aminopeptidase c) trypsin d) elastase + a, b a, c a, d b, c Choose the coenzyme of transaminases: + Pyridoxal phosphate - Thiamine - Thiamine pyrophosphate - FAD Choose an enzyme involved in the neutralization of biogenic amines: - Urease - Trypsin + Oxidase - Catalase Choose the compound that is formed from aspartate in the transamination reaction: - Pyruvate + Oxaloacetate - α-Ketoglutarate - Acetoacetate Histamine is formed in the process of: - Ammonia detoxification - Transamination of Glu - Intramolecular deamination of His + Decarboxylation of His Choose the function of GABA: - Mediator in the inflammatory reactions + Inhibitory transmitter in the central nervous system - Inhibits platelet aggregation - Exciting mediator in the central nervous system From these statements, choose the one that characterizes the serotonin: - It is synthesized in the adrenal medulla + It is a transmitter in the central nervous system - It reduces platelet aggregation - It is formed from serine in the reaction of decarboxylation Choose the correct ending of the sentence. Aminotransferases: - Use ATP as an energy source - Are localized only in the mitochondria - Catalyze the irreversible reaction + Use pyridoxal phosphate as a coenzyme Which vitamin is a part of coenzyme that is used by amino acid decarboxylases? - Riboflavin - Nicotinamide - Thiamine + Pyridoxine Catecholamines are synthesized from: + Tyrosine - Glutamate - Tryptophan - Histidine What disease is caused by the deficiency of phenylalanine hydroxylase? - Alcaptonuria + Phenylketonuria - Albinism - Tyrosinemia Melanin is synthesized from: - Methionine + Tyrosine - Tryptophan - Glutamate Which enzyme catalyzes the following reaction: Pyruvate + Glutamate ↔ Alanine + α-Ketoglutarate + Alanine aminotransferase - Aspartate aminotransferase - Glutamate dehydrogenase - Pyruvate dehydrogenase complex Match the missing component to the ornithine cycle reaction: ? + aspartate → argininosuccinate + citrulline fumarate ornithine arginine Select the appropriate enzyme for the ornithine cycle reaction: citrulline + aspartate → argininosuccinate + argininosuccinate synthetase arginase argininosuccinate lyase carbamoylphosphate synthetase I The final product of detoxification of ammonia in the liver is: + urea uric acid bilirubin carnitine Select the cause of elevated level of urea in blood: + renal failure the genetic deficiency of ornithine carbamoyltransferase protein deprivation the genetic deficiency of carbamoylphosphate synthetase I The concentration of urea in the blood is + 2.5 – 8.3 mmol / l 20 - 35 g / day 14.3 - 25.0 mmol / l 8.5 – 20.5 µmol/l Choose the amino acid that participates in the formation of disulfide bonds: + cysteine tyrosine tryptophan serotonin Choose the amino acid that is a precursor of catecholamines: cysteine + tyrosine tryptophan serotonin Select the altered chemical reaction in patients with alcaptonuria: phenylalanine → tyrosine DOPA → dopamine tyrosine → melanin + homogentisate → fumarylacetoacetate Choose the enzyme that catalyzes the reaction Glu + NH3 + ATP → Gln +ADP + H3PO4: glutaminase + glutamine synthetase glutamate dehydrogenase glutamine transferase Choose the correct statement: carbamoylphosphate synthetase I is involved in the synthesis of pyrimidine nucleotides + carbamoylphosphate synthetase I neutralizes ammonia in the liver carbamoylphosphate synthetase I is involved in the formation of the main transport form of ammonia The substrate of carbamoylphosphate synthetase I is α-ketoglutarate Select the pathology associated with DOPA decarboxylase deficiency: albinism phenylketonuria alcaptonuria + Parkinson's disease Choose the correct statement: glutamine synthetase takes part in the synthesis of pyrimidine nucleotides glutamine synthetase detoxifies ammonia in the liver + glutamine synthetase takes part in the formation of the main transport form of ammonia The substrate of glutamine synthetase is α-ketoglutarate Histones are relatively small proteins that contain many: - Sulfur containing amino acids - Aromatic amino acids + Diaminomonocarboxylicamino acids - Dicarboxylic amino acids Choose a sequence complementary to a given fragment of DNA (5'- ATCGTACCGTTA-3 '): - 5'-TGACAGAGTAGA-3 ' + 5'-TAACGGTACGAT-3 ' - 5'-ATTGCCATGCTA-3 ' - 5'-ATCGTACCGTTA-3 ' All of the following statements are correct, except: + The nucleotide composition of DNA changes in ontogenesis and depends on the physiological state of the body - Mononucleotides are joined by 3',5'-phosphodiester linkages in the DNA chain - In DNA, the content of purines is equal to the content of pyrimidines - Nucleotide sequence of one DNA chain defines such in the other chain All of these substrates are necessary for the synthesis of pyrimidine nucleotides, except: - Aspartate - Glutamine - CO2 + Glycine Choose the sources of nitrogen atoms for the purine ring: + Aspartic acid, glutamine and glycine - Aspartic acid, glutamine and ammonia - Aspartic acid and ammonia - Urea and ammonia Thioredoxin takes part in the following reaction: +ADP → dADP - UTP → CTP - dUMP → dTMP - dCMP → dUMP Which mononucleotide is used as an energy source during translation? - ATP + GTP - UTP - CTP Choose a key reaction in the synthesis of purine nucleotides: - Formation of inosine monophosphate (IMP) - Formation of carbamoyl phosphate + Formation of phosphoribosylamine - Formation of phosphoribosylpyrophosphate Synthesis of nucleotides de novo requires participation of the active form of: - Ascorbic acid - Pantothenic acid + Folic acid - Arachidonic acid In a nucleoside structure nitrogenous base and pentose are linked by: - Hydrogen bond - Peptide bond - Phosphodiester bond + Glycosidic bond Which of the following substances can block the synthesis of thymidylate? - Folic acid + Methotrexate - Potassium orotate - Methyluracil Choose the substrates used by DNA polymerase in the process of replication: + dATP, dCTP, dGTP, dTTP - dADP, dCDP, dGDP, dTDP - ATP, CTP, GTP, TTP - dAMP, dTMP, dCMP, dGMP Choose a statement that correctly describes the work of DNA polymerase: - The daughter strand of DNA is synthesized using deoxyribonucleosidemonophosphates as substrates + The DNA daughter chain is elongated by the addition of deoxyribonucleoside triphosphates to a free 3'-OH group (with elimination of pyrophosphate) - The DNA daughter chain is elongated using deoxyribonucleoside diphosphates as substrates - Reads information from the 5'-end of maternal DNA chain If the synthesis of fragment C begins, what other segment is synthesized? -A -B -C +E Fragment C is synthesized: - From the middle to both ends simultaneously + Towards the replication fork - Away from the replication fork - In a direction from the 3'- to the 5'-end Fragment E is synthesized: - From the middle to both ends simultaneously - Towards the replication fork + Away from the replication fork - After the D-segment Choose the enzyme that joins fragments D and E: - DNA polymerase - RNA polymerase - Endonuclease + DNA ligase A region of DNA in which the synthesis of both chains occurs in the two replication forks moving in opposite directions, is called: - Origin + Replicon - Transposon - Replisome All listed components are required for the synthesis of a leading DNA chain in replication, except: - dATP, dGTP, dCTP, dTTP - DNA polymerase-α + DNA polymerase-ε - DNA polymerase-δ Specify the chemical nature of the primer in vivo: - Polyribonucleotide + Oligoribonucleotide - Polydeoxyribonucleotide - Oligopeptide Choose an enzyme that synthesizes RNA-primer during replication: - Reverse transcriptase + Primase - Helicase - DNA ligase The term “Okazaki fragments”corresponds to: - Segments of DNA leading strand + Segments of DNA lagging strand - Segments of maternal DNA - Segments of messenger RNA What transformations occur during post-transcriptional mRNA processing? a) splicing b) capping c) polyadenylation d) elongation a, b + a, b, c b, d a, c Regulation of protein synthesis at the level of transcription may be implemented by: a) induction b) repression c) capping d) emulsification + a, b c, d a, b, c b, d Choose the correct statement: a) polyadenylic “tail” in the mRNA molecule may play a protective role b) RNA polymerase II catalyzes the formation of the mature form of the mRNA c) mRNA capping is necessary for its protection against nucleases d) splicing - this is the stage of replication a, b, c + a, c a, b a, d The active site of the aminoacyl-tRNA synthetase in the process of recognition reacts with: a) amino acid b) ATP c) tRNA d) GTP a, c a, b + a, b, c a, d Choose compounds which are formed by the action of the aminoacyl-tRNA synthetase: a) amino acid b) aminoacyl adenylate c) aminoacyl-tRNA d) GTP a, b, c + b, c b, d a, c What factors are necessary for the initiation of translation? a) methionyl-tRNA b) GTP c) codons AUG or GUG d) ATP a, c b, c, d + a, b, c c, d Choose the factors necessary for the elongation of translation: a) codons AUG or GUG b) release factors c) aminoacyl-tRNA d) GTP a, b b, c only d + c, d Choose the factors necessary for the termination of translation: a) ATP b) codons UAA, UGA or UAG c) aminoacyl-tRNA d) GTP a, b b, c + b, d a, b, c Choose processes that require GTP energy during translation: a) formation of peptide bonds b) attaching aminoacyl-tRNA to the aminoacyl center c) movement of the ribosome along mRNA d) formation of initiation complex a, b, c + b, c, d a, c a, b mRNA is involved in the processes of: a) replication b) transcription c) translation d) recognition + b, c a, c, d only b only c tRNA is involved in the processes of: a) replication b) transcription c) translation d) recognition a, b, c b, c + c, d only b Specify the properties of the RNA polymerase: a) primer is not required for its work b) RNA is synthesized in the direction from 5'- to 3'-end c) takes part in the polymerization of amino acids d) DNA molecule serves as a template for it a, c + a, b, d b, d only d Choose the place of parathyrin synthesis: follicular thyroid cells C-cells of the thyroid gland + parathyroid glands β-cells of the islets of Langerhans Select the disease that develops with hypofunction of the thyroid gland: + myxedema diabetes mellitus acromegaly diabetes insipidus Select the initial substrate for eicosanoid synthesis: cholesterol + arachidonic acid tyrosine tryptophan Specify the chemical nature of glucagon: simple protein derivative of cholesterol + peptide amino acid derivative Specify the type of natriuretic peptide receptor: the intracellular cytosolic 7-TMS + 1-TMS the intracellular nuclear Specify the type of insulin receptor: the intracellular cytosolic the intracellular nuclear 7-TMS + 1-TMS Specify the type of thyroxine receptor: the intracellular cytosolic + the intracellular nuclear 7-TMS 1-TMS Choose the target tissues of glucagon: adrenal gland thyroid gland kidney + liver Choose the target cells of aldosterone: adrenal gland thyroid gland + kidney liver Choose the target cells of adrenocorticotropic hormone: + adrenal gland thyroid gland kidney liver Choose the main metabolic effect of insulin: increases the blood glucose level + lowers the blood glucose level increases renal water reabsorption increases the sodium secretion in kidney Choose the right combination “enzyme - its function in signal transmission through the 7-TMS receptor”: adenylate cyclase – formation of the inositol triphosphate + phospholipase C – formation of the diacylglycerol protein kinase A– formation of cyclic guanosine monophosphate protein kinase C – formation of cyclic adenosine monophosphate Choose the right combination “substance –its function in signal transmission through 7-TMS receptors”: + calmodulin – binding of calcium ions inositol triphosphate – activation of protein kinase A cyclic adenosine monophosphate – activation of protein kinase C cyclic guanosine monophosphate – opening of calcium channels in calciosomes Choose the correct statement about releasing hormones of hypothalamus: - act on the 1-TMC receptors - act on the cytosolic receptors - act on the posterior pituitary receptors + act on the 7-TMS receptors Choose the correct statement. Membrane-bound guanylate cyclase is activated by: - Aldosterone - Vasopressin - Insulin + Atrial natriuretic peptide Choose the hormone whose receptor is associated with heat shock proteins: - Adrenaline + Cortisol - Glucagon - Calcitonin It binds with 1-TMC-receptor: - Testosterone - Adrenaline + Prolactin - Thyrotropin Calcitriol receptor relates to the family of: - 7-TMS receptors - 1-TMS receptors - Cytosolic receptors + Nuclear receptors Which hormone binds to nuclear receptors? + Thyroxine - Progesterone - Cortisol - Aldosterone Choose the correct statement regarding the mechanism of cGMP action: - Activates adenylate cyclase - Activates guanylate cyclase - Is a second messenger in the action of steroid hormones on the cell + Contributes to the smooth muscle relaxation All these substances serve as second messengers in the action of hormones, except: - Inositol triphosphate - cAMP - Diacylglycerol + GTP Gs-proteins in the course of time lose their ability to activate adenylate cyclase. This is caused by: - ATPase activity of α-subunit - ATPase activity of γ-subunit + GTPase activity of α-subunit - Phospholipase activity of Gs-protein Aldosterone receptor have all of the domains, except: - Hormone binding + G-protein-binding - Regulating transcription - DNA-binding Glucocorticoid receptor is characterized by: + The presence of zinc fingers - The absence of heat shock proteins - The activation of phospholipase C - The localization in the plasma membrane Which of the following may cause the resistance to the hormone? a) disorder of hormone synthesis in the endocrine gland b) receptor anomaly c) the appearance of antibodies to receptor d) deficiency of the pituitary tropic hormones a, b, c + b, c b, d b, c, d Choose correct statements about the 1-TMS receptors: a) contain a single transmembrane segment b) interact with Gαi - proteins c) are localized in the nucleus of the cell d) have enzymatic activity or associated with cytosolic tyrosine kinases a, b b, c only c + a, d 1-TMS receptor can display activity of: a) guanylate cyclase b) adenylate cyclase c) tyrosine kinase d) tyrosine phosphatase + a, c, d a, b a, b, d c, d Choose correct statements about the cAMP-dependent protein kinase A: a) tetramer consisting of two regulatory and two catalytic subunits b) dimer consisting of one regulatory and one catalytic subunit c) phosphorylates target proteins d) its inhibitor is cAMP a, b, c + a, c b, d only d Choose hormones that bind with nuclear receptors: a) testosterone b) triiodothyronine c) estrogens d) aldosterone a, b + b, c c, d a, c, d Choose the correct answers. Amino acids are precursors to: a) iodothyronines b) estrogens c) serotonin d) adrenaline (epinephrine) b, c a, b + a, c, d b, c, d Choose the hormones that are synthesized from cholesterol: a) estrogens b) iodothyronines c) aldosterone d) androgens a, b, c a, b a, c + a, c, d The synthesis of cortisol is controlled by: a) corticotropin-releasing hormone b) adrenocorticotropic hormone c) vasopressin d) adrenaline a, d + a, b a, c c, d Choose the enzymes involved in the synthesis of thyroid hormones: a) thyroid peroxidase b) 5`-deiodinase c) catalase d) aromatase a, b a, c + a, b, c b, c, d Choose the correct statements. The synthesis of thyroid hormones includes: a) delivery of iodine to the thyroid gland b) binding of iodine to the tyrosine residues in thyroglobulin c) conversion of T3 to T4 in peripheral tissues d) conversion of T4 to T3 in peripheral tissues b, d a, b, c + a, b only a Choose the correct sequence of events in the cascade mechanism of hormonal signal transduction: a) the phosphorylation of proteins (enzymes) b) the interaction of the hormone with a specific receptor c) activation of protein kinase d) the formation of second messenger +b→d→c→a a→b→c→d d→a→b→c c→d→b→a Choose the correct sequence of participants used in signal transduction through the 7-TMS receptors: a) 7-TMS receptor b) protein kinase C c) G-protein d) phospholipase C c→a→d→b d→a→b→c +a→c→d→b b→c→a→d Choose the correct sequence of participants used in signal transduction through the phospholipase C: a) G-protein b) diacylglycerol and inositol triphosphate c) phospholipase C +c→a→b a→c→b b→a→c b→c→a Choose the correct sequence of events in the interaction of hormones with intracellular receptors: a) the release of the receptor from the chaperones (hsp proteins) b) the interaction of a hormone with receptor c) activation of transcription a→b→c +b→a→c b→c→a a→c→b Identify the correct sequence of events in the interaction of the insulin with receptor: a) stimulation of the receptor tyrosine kinase activity b) 1-TMS receptor c) the phosphorylation of insulin receptor substrates (IRS1 and IRS2) c→b→a c→a→b +b→a→c a→b→c Choose the correct sequence of participants in the growth hormone signaling pathway: a) STAT-proteins b) Janus-kinase c) 1-TMS receptor +c→b→a b→a→c b→c→a a→b→c Identify the correct sequence of events in binding of glucagon to the 7-TMS receptor of the hepatocyte: a) activation of protein kinase A b) activation of the G-protein c) activation of glycogen phosphorylase d) formation of cAMP b→c→a→d a→b→c→d +b→d→a→c d→b→c→a Identify the correct sequence of events in binding of glucagon to the 7-TMS receptor of the hepatocyte: a) activation of protein kinase A b) activation of the G-protein c) activation of glycogen phosphorylase d) formation of cAMP b→c→a→d a→b→c→d +b→d→a→c d→b→c→a Identify the correct sequence of events in binding of vasopressin to 7-TMS receptor type V1: a) activation of the G-protein b) activation of phospholipase C c) formation of diacylglycerol and inositol triphosphate d) opening of calcium channels in the ER d→a→b→c +a→b→c→d a→d→b→c c→d→a→b Determine the correct sequence of events in the binding of atrial natriuretic peptide to 1-TMS receptor: a) formation of cGMP b) dimerization of the receptor c) activation of protein kinase G d) activation of guanylate cyclase receptor domain +b→d→a→c a→b→d→c d→a→c→b c→b→a→d Identify the correct sequence of events in the binding of prolactin to the 1-TMS receptor: a) activation of Janus kinase (Jak-protein) b) dimerization of the receptor c) activation of transcription d) phosphorylation of STAT-proteins d→b→a→c c→a→b→d +b→a→d→c a→b→d→c Identify the correct sequence of events in the binding of the hormone to 7-TMS receptor: a) the activation of adenylate cyclase b) GTP hydrolysis under the action of α-subunit of the G-protein c) replacement of GDP by GTP in the G-protein d) the dissociation of G-protein to α- and βγ-subunit a→b→d→c b→a→c→d d→b→a→c +c→d→a→b Melatonin receptors are localized in: + the cell membrane - cytosol - lysosomes - ribosomes 5'-deiodinase is involved in the synthesis of triiodothyronine. Choose the trace element needed for this enzyme: -I -F - Fe + Se The secretion of growth hormone is inhibited by: + Glucose - Thyroxine - Androgens - Triiodothyronine Choose the effect caused by thyroid hormones (T3 and T4): + Activation of synthesis of enzymes of the respiratory chain - Repression of Na+/K+ -ATPase synthesis - Inhibition of Ca2+-ATPase synthesis - Suppression of basal metabolic rate Which enzyme is required for the synthesis of follicular thyroid hormones? - Aromatase + Thyroid peroxidase - 5-Deiodinase - Glutathione peroxidase The doctor suspected that the patient has Itsenko - Cushing syndrome. The diagnosis confirmation was provided by the finding of high blood level of: + Cortisol - Aldosterone - Glucagon - Adrenaline All these effects are characteristic of insulin, except: - Insulin increases glucose uptake in adipocytes - It activates glycogen synthesis - It activates the synthesis of fatty acids + It interacts with nuclear receptors All statements regarding insulin are true, except: - Insulin promotes glucose transport in skeletal muscle - It stimulates the synthesis of glycogen in the liver + Increases lipolysis in adipose tissue - Inhibits gluconeogenesis in the liver Insulin is necessary for transport of glucose to the following pair of tissues: - The brain and skeletal muscles - Skeletal muscle and liver - Erythrocytes and liver + Adipose tissue and skeletal muscle Binding of insulin to its receptor results in stimulation of enzyme activity, except for: + Glycogen phosphorylase - Glycogen synthase - Acetyl-CoA carboxylase - Fatty acid synthase Diabetes is characterized by all of the following metabolic changes, except: - Simulation of gluconeogenesis + Stimulation of lipogenesis - Increased lipolysis - Suppressed glycogenesis Glucocorticoids have a catabolic effect on: - Liver + Skeletal muscle - Brain - The adrenal glands All the following compounds are produced in the liver, except: -Fatty acids +Chylomicrons -Triacylglycerols -Ketone bodies All the following substances take part in heme synthesis, except: -Protoporphyrin IX -Glycine -Succinyl-CoA +Protoporphyrin X One of the main functions of the liver is to maintain blood glucose level. Even with the complete exclusion of carbohydrates from the diet, glucose blood level is maintained mainly due to: -Glycolysis +Gluconeogenesis -Glycogenesis -Glycogenolysis The relative content of conjugated bilirubin from total bilirubin in blood plasma is: -5% -10% +25% -40% Unconjugated bilirubin in blood is transferred bound to albumin because: +It is poorly soluble in water -It can pass through the renal filter -It is excreted with urine -It is poorly soluble in lipids Indirect bilirubin is produced in: - Myocytes - Platelets +Macrophages - Hepatocytes Physiological jaundice develops in first week in newborns. Choose one of the causes of the jaundice: - High activity of the enzyme UDP-glucuronyl transferase +Excess of estrogens - Lack of estrogens - Excess of direct bilirubin Key enzyme of heme synthesis requires the following vitamin: +Pyridoxin -Thiamine -Biotin -Retinol Choose the metal, which inhibits heme synthase: +Lead -Manganese -Sodium -Calcium Choose the coenzyme of biliverdin reductase: +NADPH.H+ -NAD+ -FAD -FMN Feces normally contain: -Direct bilirubin +Stercobilin -Urobilin -Mesobilirubin The main protein involved in the binding of heavy metals in the liver is: +Metallothionein -Ceruloplasmin -Transferrin -Haptoglobin Detoxication of xenobiotics: a) is provided by enzymes of the endoplasmic reticulum b) increases the polarity of the substance c) occurs under anaerobic conditions d) takes place with participation of cytochrome Р 450 + a, b, d a, b, c b, c, d only a Choose the substances, which are detoxified in the liver by the mechanism of oxidation: a) alcohol b) catecholamines c) ammonia d) biogenic amines + a, b, d a, d b, c only b Choose the substances, which are detoxified in the liver: a) bilirubin b) NH3 c) xenobiotics d) sucrose b, d only a only b + a, b, c Ethanol oxidation has the following characteristics: a) occurs mostly in the liver b) catalyzed by alcohol dehydrogenase c) can be catalyzed by microsomal ethanol oxidizing system (MEOS) d) results in the formation of fructose + a, b, c b, c, d a, c b, d Decreased antitoxic function of the liver is accompanied by the following changes in the urine: a) increased indican concentration after loading with diet protein b) decreased indicant concentration after loading with diet protein c) increased hippuric acid concentration after administration of sodium benzoate d) decreased hippuric acid concentration after administration of sodium benzoate; + b, d a, c c, d a, b, d Obstructive jaundice is accompanied by increasing blood level of: a) direct bilirubin b) stercobilin c) alkaline phosphatase activity d) acid phosphatase activity a, b, c c, d + a, b b, d Hemolytic jaundice is accompanied by: a) direct bilirubin increase in the blood b) stercobilin increase in urine c) indirect bilirubin increase in the blood d) urobilin appearance in urine b, d a, b + b, c a, c, d Hepatic jaundice is accompanied by: a) increased direct bilirubin in the blood b) appearing of urobilin in urine c) increased alanine aminotransferase activity in serum d) appearing of indirect bilirubin in urine + a, b, c b, d c, b a, c, d Decreased antitoxic function of the liver is accompanied by the following changes in the blood: a) increasing ammonia b) increasing indirect bilirubin c) increasing total protein content d) increasing non-protein blood nitrogen (urea fraction) a, b, c b, c, d + a, b c, d Choose the enzymes whose serum activity is determined to diagnose the liver injury: a) choline esterase b) fructose-1-phosphate aldolase (aldolase B) c) glycogen synthase d) amylase + a, b b, c, d a, c a, b, d Choose the enzymes whose serum activity is determined to diagnose the liver injury: a) aspartate aminotransferase b) alkaline phosphatase c) citrate synthase d) elastase b, c, d + a, b a, d b, c Choose the enzymes whose serum activity is determined to diagnose the liver injury: a) sorbitol dehydrogenase b) fructose-1-phosphate aldolase c) malate dehydrogenase d) citrate dehydrogenase + a, b b, c, d a, b, c c, d All statements about the structure of hemoglobin are true, with the exception of: - The molecule of the major adult hemoglobin is composed of two identical α- subunits and two identical β-subunits - Hemoglobin subunit (protomer) consists of a single polypeptide chain and a heme - Heme is a complex of protoporphyrin with the iron atom bound at the center + The iron in hemoglobin changes the oxidation state in the course of oxygen binding or release Which of the following statements about 2,3-diphosphoglycerate is right? - Pentose phosphate pathway intermediate - Competes with oxygen upon binding to the heme in hemoglobin - Prevents oxygen transfer to the tissues + Facilitates oxygen transfer to the tissues The development of methemoglobinemia may be due to: + Oxidizing agent (nitrites, nitrates) poisoning - High partial pressure of oxygen - Hereditary defect of ceruloplasmin - Low partial pressure of carbon dioxide Which state can develop during prolonged diarrhea? - Relative hypoproteinemia + Relative hyperproteinemia - Absolute hyperproteinemia - Absolute hypoproteinemia Which state can develop in patient suffering from bronchial asthma? - Metabolic acidosis - Metabolic alkalosis + Respiratory acidosis - Respiratory alkalosis Primary hemic hypoxia occurs in: - Overdose of barbiturates + Anemia associated with a significant decrease in erythrocytes - Decrease in the partial pressure of oxygen in the inspired air - Hepatitis Choose the index used in clinical practice to assess acid-base status of the patient: - Hemoglobin concentration + The partial pressure of carbon dioxide - The partial pressure of carbon monoxide - Concentration of phosphate ions Plasma proteins have all these functions, except: - Maintain the constancy of the colloid osmotic pressure - Participate in the immune response - Transportation + Contraction Albumins perform all of the following functions, except: - Create a colloid osmotic pressure of blood - Transport many substances - Serve as the reserve of amino acids + Have a protective function Haptoglobin - is: + The globulin which binds free hemoglobin in plasma - The globulin bound with bilirubin - The globulin bound with myoglobin - The globulin that binds calcium Paraproteinemia - is: - Increase in total protein - Decrease in total protein - Altered ratio of protein fractions + Appearance of a protein in blood that is absent in healthy individuals The reduced content of haptoglobin in blood results in: + Hemoglobinuria - Hyperuricuria - Hypopotassiumemia - Hyperbilirubinemia Hageman factor: a) is a serine protease b) is activated after contact with a surface different from normal endothelium c) is activated after contact with the membrane of activated platelets d) is activated by tissue factor (factor III) a, c + a, b, c b, d only a Initiation complex of extrinsic pathway of coagulation contains: a) tissue factor (factor III) b) Сa2+ c) factor XII d) factor VII c, d + a, b, d only b a, c Tenase complex contains: a) factor VIIIa b) factor IXa c) Ca2+ d) fibrinogen b, d + a, b, c a, c a, d Choose the correct statements about role of calcium ions (factor IV) in blood coagulation: a) provide binding of factors II, VII, IX, X on the plasma membrane of the activated platelets b) can act as second messengers in transducing hormonal signal c) stimulate lipid peroxidation d) activate some plasma clotting factors b, c a, b, d + a, d b, c, d Antithrombin III: a) is a natural primary anticoagulant b) is a natural secondary anticoagulant c) irreversibly inhibits most of serine proteases of coagulation system d) destroys clotting factors V and VIII + a, c b, d only a only b The anticoagulant activity of heparin is based on: a) its ability to bind calcium ions b) its ability to activate antithrombin III c) its ability to form unstable complexes with some clotting factors, thus limiting their participation in coagulation process d) its ability to perform non-enzymatic fibrinolysis b, d a, c + b, c, d only c Choose the plasminogen activators: a) α2-macroglobulin b) tissue plasminogen activator c) urokinase d) protein С (S) a, d b, c + b, c, d a, b, d Protein С: a) is a serine protease b) destroys tissue factor c) hydrolyses factor Va d) is activated by protein S + a, c, d only b b, c a, d Vitamin K takes part in the synthesis of γ-carboxyglutamate in: a) factor VII b) factor V c) factor Х d) factor II b, c, d only c + a, c, d only d Protein S: a) is a cofactor of proteinС b) is an inhibitor of protein С c) is a vitamin K-dependent protein d) takes part in hydrolysis of factor VIII + a, c, d only b a, b c, d Factor Хa: a) is a constituent of prothrombinase complex b) its activity depends on the amount of factor VIII c) is a constituent of tenase complex d) is a vitamin K-dependent protein + a, b, d c, d b, c a, c, d Factor ХIII: a) is a transpeptid