Quiz
Biochemistry MCQs 3rd Coloquim PMU 2nd Year
Perguntas do quiz (42)
1Which are the regulatory enzymes in glycolysis?
- AHexokinase
- BGlucose-6-phosphate Isomerase
- CPhosphofructokinase
- DPhosphoglycerate Mutase
- EPyruvate Kinase
2Which enzymes participate in pentose phosphate pathway?
- AGlucose-6-phosphate Dehydrogenase
- BTransaldolase
- CTransketolase
- DPhosphofructokinase
- EPyruvate Kinase
3Gluconeogenesis occurs in:
- ACytosol
- BEndoplasmic Reticulum
- CMitochondria
- DBoth Cytosol and Endoplasmic Reticulum
- ECytosol, Mitochondria and Endoplasmic Reticulum
4Which of the molecule is "linkage" between the citric acid cycle and gluconeogenesis?
- ACitrate
- BIsocitrate
- CMalate
- DOxaloacetate
- ESuccinyl-CoA
5Which of the vitamins is involved in gluconeogenesis as coenzyme?
- AVitamin C
- BVitamin H (biotin)
- CVitamin B1 (thiamine pyrophosphate)
- DVitamin PP (NAD, NADH)
- EVitamin B2 (FAD, FMN)
6Show the energy source responsible for gluconeogenesis energy supply:
- AGTP and UTP
- BATP and GTP
- CATP and UTP
- DAcetyl-CoA
- EGlucose-6-Phosphate
7Which of the following citric acid cycle intermediates, derived from α-amino acids, give carbon atoms for gluconeogenesis?
- Acitrate
- Bpyruvate
- Csuccinyl-CoA
- Dα-ketoglutarate
- Eoxaloacetate
8Which of the following is true?
- Athe enzyme activity of fructose 1,6-bisphosphatase is increased by ΑΤΡ
- Bthe enzyme activity of fructose 1,6-bisphosphatase is increased by ADP
- Cthe enzyme activity of fructose l,6-bisphosphatase is decreased by ATP
- Dthe enzyme activity of fructose 1,6-bisphosphatase is decreased by ADP
- Efructose 2,6-bisphosphate is the most potent activator for gluconeogenesis and Inhibitor for glycolysis
9Which of the following enzymes are regulatory in gluconeogenesis:
- APyruvate carboxylase
- BGlucose-6-phosphatase
- CPhosphofructokinase
- DPyruvate kinase
- EΡΕΡ carboxykinase
10Which of the following hormones stimulate gluconeogenesis:
- Ainsulin
- Bglucagon
- Ccortisol
- Dadrenaline
11Gluconeogenesis:
- AIs stimulated by insulin
- BIs stimulated by glucagon
- CIs major pathway in liver and kidneys
- DCan also be performed in muscles
- ECauses a decrease in blood glucose level
12Which are the true statements about regulation of glycolysis?
- AHexokinase is not a regulatory enzyme
- BGlucokinase is not inhibited allosterically by glucose-6-phosphate
- CPhosphofructokinase 1 is the most important regulatory enzyme
- DFructose-2,6-bisphosphate activates glycolysis
- EInsulin causes a decrease in the concentration of fructose-2,6-bisphosphate
13How many molecules of ATP are created from NADH+H+ generated from 1 molecule glucose in glycolysis, if transported into the mitochondria by malate shuttle? Explain why?
- A2
- B3
- C4
- D6
- E8
14Which of the following statements about insulin and glucagon are true?
- AInsulin is secreted in periods of starvation
- BInsulin is secreted by α-cells of the pancreas to decrease blood glucose level after meal
- CGlucagon is secreted in case of low blood glucose levels
- DInsulin stimulates pentose phosphate pathway
- EGlucagon is the main hormone that stimulates gluconeogenesis
15Glycogen:
- AIs a linear polymer composed only of glucose residues
- BIs synthesized in response to insulin stimulation over the main regulatory enzyme- the branching enzyme
- CIs present at any cell but most prominently in liver and muscle cells
- DIs synthesized in periods of starvation
- EIts regulatory enzymes both in synthesis and degradation can be controlled allosterically as well as through reversible covalent modification
16Which of the following is TRUE?
- Athe main regulative enzyme in glycolysis is phosphofructokinase 1
- Bthe main regulative enzyme in glycolysis is glyceraldehyde-1-phosphate dehydrogenase
- Chexokinase involved in glycolysis is regulated by product of the reaction- glucose-6-phosphate
- Dpyruvate kinase involved in glycolysis is regulated by covalent modification (reversible phosphorylation/ dephosphorylation) only in the liver
- Epyruvate kinase involved in glycolysis is regulated by covalent modification (reversible phosphorylation/ dephosphorylation) only in the tissues
17By which of the following fatty acids derive carbon atoms for the gluconeogenesis?
- Acitrate
- Bpropionate
- Cpyruvate
- Dlactate
- Eacetyl-COA
18Which are the common metabolites for glycolysis and pentose phosphate pathway?
- AErythrose-4-phosphate
- BFructose-1,6-bisphosphate
- CGlucose-6-phosphate
- DGlyceraldehyde-3-phosphate
- EDihydroxyacetone phosphate
- FFructose-6-phosphate
- GPyruvate
19Which of the following statements about glycogen degradation in liver are true?
- AThe regulatory enzyme is glycogen phophorylase
- BThe regulatory enzyme is debranching enzyme
- CThe regulatory enzyme is activated by ATP and glucose-6-phosphate
- DIt is a source of energy for the liver itself
- EIt is most fast activated mechanism for maintenance of blood glucose level in periods of fasting
- FThe degradation stops till glucose-6-phosphate
20Which of the following statements about fructose are true?
- AIt is absorbed mainly through GLUT5
- BCan be metabolized in muscles by fructokinase and enter glycolysis in one step
- CCan be metabolized in liver, skeletal muscles, spermatozoa and other extrahepatic tissues but by different enzymes
- DA deficiency in aldolase B causes fructose intolerance
- EIn liver fructose enters glycolysis at the level of trioses-glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
21In which of the following pathways does UDP participate?
- AGlycolysis
- BGluconeogenesis
- CSynthesis of glycogen
- DDegradation of glycogen
- EGalactose metabolism
- FPentose phosphate pathway
22Glucagon secretion increases:
- Aat high insulin levels
- Bat low insulin levels
- Cat high blood glucose content
- Dat low blood glucose content
- Ein fasting
23Which of the following is TRUE?
- Aliver glycogen stores and exports glucose to maintain blood glucose
- Bliver and muscles lack glucose-6-phospatase
- Cthe synthesis of glycogen is initiated by the formation of glycogen primer
- Dthe cleavage of glycogen by glycogen phosphorylase yields UDPGlc
24Which of the following is TRUE
- Aglycogen phosphorylase is active phosphorylated
- Bhormones like glucagon and adrenaline increase glycogenolysis
- Ca rise in cAMP concentration activates glycogen synthase
- Dinsulin increases glycogenolysis
25Which are the major precursors for glucose production via gluconeogenesis?
- Alactate
- Bglucogenic amino acids
- Cglycerol
- Dfructose
- Eacetyl-CoA
26Which of the following about pentose phosphate pathway (PPP) is TRUE?
- Ait generates NADPH for reductive biosynthesis
- Bit generates ribose phosphate for nucleotide and nucleic acids formation
- Cthe enzymes of PPP are mitochondrial
- DPPP protects the erythrocytes against hemolysis
27Which of the following is TRUE?
- Acitrate and ATP are allosteric inhibitors of phosphofructokinase-1
- Bfructose-2,6-bisphosphate is an allosteric activator of phosphofructokinase-1
- Cphosphofructokinase-1 activity is increased by insulin
- Dphosphofructokinase-1 activity is increased by glucagon
28Which of the following enzymes participate in glycolysis?
- AHexokinase
- BGlucose-6-phosphatase
- CPhosphofructokinase
- DPyruvate kinase
- EPEP carboxykinase
29What is the ATP production in complete glucose oxidation to CO2 and water (mol ATP per mol of glucose; NADH is transported into mitochondria by the malate shuttle)?
- A32
- B38
- C24
- D12
- E2
30Insulin stimulates:
- Aglycolysis
- Blipolysis
- Cgluconeogenesis
- Dglycogen degradation
- Eglycogen synthesis
31Which of the following statements about pentose phosphate pathway are true?
- AIt is the major donor of NADH+H+
- BIt is the major donor of NADPH+H+
- CIt is located in the mitochondria
- DIts major goal is generation of energy
- Eit produces reducing agents for various synthesis but also ribose for nucleic acids formation
32Which are the regulatory enzymes in gluconeogenesis?
- AGlucokinase
- BPhosphoglucomutase
- CPhosphoenolpvruvate carboxykinase
- DPyruvate kinase
- EPyruvate carboxylase
- FGlucose-6-phosphatase
- GFructose-1,6-bisphosphatase
33Galactose:
- Als metabolized both in liver and extrahepatic tissues
- BIs metabolized only in liver
- CIts metabolism requires UDP
- DCan be used for maintenance of blood glucose level
- EGalactosemia type I (classical) is caused by deficiency in galactokinase
34Which of the following statements about carbohydrate metabolism in red blood cells are true?
- AGlycolysis can be performed either in aerobic or anaerobic conditions
- BThe terminal product of glycolysis is always lactate
- CRBC contain smaller amounts of 2,3 bisphosphoglycerate compared the rest of the cells
- DPentose phosphate pathway is of vital importance for the RBC
- ERBC participate in Cori Cycle
35Which of the following is TRUE?
- Aall of the enzymes of glycolysis are in the cytosol
- Bglucokinase is an isoenzyme of hexokinase in liver and pancreatic β-cells
- Cphosphofructokinase-1 is a major regulatory enzyme of glycolysis
- Dglycolyis is a pathway that can function only aerobically
36Glycogen:
- Als a branched polymer composed only of glucose residues
- BThe main regulatory enzyme of its synthesis - glycogen synthase, is activated by epinephrine
- Cls present most prominently in liver and muscle cells but has different function in them
- DThe regulatory enzymes both in synthesis and degradation can be controlled allosterically as well as through reversible covalent modification
- Eα-(1->6) glycosidic bond cleavage is executed by glycogen phosphorylase
37Which of the following statements about insulin and glucagon are true?
- AInsulin is secreted in response to hyperglycemia
- BInsulin is secreted in response to hypoglycemia
- CGlucagon is activator of gluconeogenesis and glycogen degradation
- DInsulin inhibits pentose phosphate pathway
- EInsulin activates phosphofructokinase 1 and thus glycolysis
38Which of the following statements about regulation of carbohydrate metabolism are true?
- AFructose-2,6-bisphosphate is aIIosteric activator of glycoiysis and inhibitor of giuconeogenesis
- BFructose-2,6-bisphosphate is allosteric inhibitor of glycoiysis and activator of giuconeogenesis
- CATP and citrate are inhibitors of glycolysis
- DAMP is an activator of glycoiysis
39Which of the following statements are true?
- ADeficiency in glucose-6-phosphate dehydrogenase may cause haemolytic anaemia
- BFructose is metabolized only in liver
- CFructosuria is caused by deficiency in fructokinase
- DGlucose is transported in liver and pancreas through GLUT 3
40Which of the following statements about regulation of glycolysis are TRUE?
- AHexokinase is not a regulatory enzyme
- BGlucokinase is not inhibited allosterically by glucose-6-phosphate
- CPhosphofructokinase 1 is the most important regulatory enzyme
- DFructose-2,6-bisphosphate activates glycolysis
- EInsulin causes a decrease in the concentration of fructose-2,6-bisphosphate
41Which of the following is TRUE?
- Aglycogen phosphorylase is active dephosphorylated
- Bhormones like glucagon and adrenaline increase glycogen synthesis
- Ca rise in cAMP concentration activates glycogen phosphorylase
- Dinsulin increases glycogen synthesis
42How many molecules of ATP are created from NADH+H+ generated from 1 molecule glucose in glycolysis, if transported into the mitochondria by glycerol-3-phosphate shuttle? Explain why?
- A2
- B3
- C4
- D5
- E6
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