Pregunta 1
Pregunta
Which are the regulatory enzymes in glycolysis?
Pregunta 2
Pregunta
Which enzymes participate in pentose phosphate pathway?
Pregunta 3
Pregunta
Gluconeogenesis occurs in:
Pregunta 4
Pregunta
Which of the molecule is "linkage" between the citric acid cycle and gluconeogenesis?
Respuesta
-
Citrate
-
Isocitrate
-
Malate
-
Oxaloacetate
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Succinyl-CoA
Pregunta 5
Pregunta
Which of the vitamins is involved in gluconeogenesis as coenzyme?
Pregunta 6
Pregunta
Show the energy source responsible for gluconeogenesis energy supply:
Respuesta
-
GTP and UTP
-
ATP and GTP
-
ATP and UTP
-
Acetyl-CoA
-
Glucose-6-Phosphate
Pregunta 7
Pregunta
Which of the following citric acid cycle intermediates, derived from α-amino acids, give carbon atoms for gluconeogenesis?
Respuesta
-
citrate
-
pyruvate
-
succinyl-CoA
-
α-ketoglutarate
-
oxaloacetate
Pregunta 8
Pregunta
Which of the following is true?
Respuesta
-
the enzyme activity of fructose 1,6-bisphosphatase is increased by ΑΤΡ
-
the enzyme activity of fructose 1,6-bisphosphatase is increased by ADP
-
the enzyme activity of fructose l,6-bisphosphatase is decreased by ATP
-
the enzyme activity of fructose 1,6-bisphosphatase is decreased by ADP
-
fructose 2,6-bisphosphate is the most potent activator for gluconeogenesis and Inhibitor for glycolysis
Pregunta 9
Pregunta
Which of the following enzymes are regulatory in gluconeogenesis:
Respuesta
-
Pyruvate carboxylase
-
Glucose-6-phosphatase
-
Phosphofructokinase
-
Pyruvate kinase
-
ΡΕΡ carboxykinase
Pregunta 10
Pregunta
Which of the following hormones stimulate gluconeogenesis:
Respuesta
-
insulin
-
glucagon
-
cortisol
-
adrenaline
Pregunta 11
Pregunta
Gluconeogenesis:
Respuesta
-
Is stimulated by insulin
-
Is stimulated by glucagon
-
Is major pathway in liver and kidneys
-
Can also be performed in muscles
-
Causes a decrease in blood glucose level
Pregunta 12
Pregunta
Which are the true statements about regulation of glycolysis?
Respuesta
-
Hexokinase is not a regulatory enzyme
-
Glucokinase is not inhibited allosterically by glucose-6-phosphate
-
Phosphofructokinase 1 is the most important regulatory enzyme
-
Fructose-2,6-bisphosphate activates glycolysis
-
Insulin causes a decrease in the concentration of fructose-2,6-bisphosphate
Pregunta 13
Pregunta
How 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?
Pregunta 14
Pregunta
Which of the following statements about insulin and glucagon are true?
Respuesta
-
Insulin is secreted in periods of starvation
-
Insulin is secreted by α-cells of the pancreas to decrease blood glucose level after meal
-
Glucagon is secreted in case of low blood glucose levels
-
Insulin stimulates pentose phosphate pathway
-
Glucagon is the main hormone that stimulates gluconeogenesis
Pregunta 15
Respuesta
-
Is a linear polymer composed only of glucose residues
-
Is synthesized in response to insulin stimulation over the main regulatory enzyme- the branching enzyme
-
Is present at any cell but most prominently in liver and muscle cells
-
Is synthesized in periods of starvation
-
Its regulatory enzymes both in synthesis and degradation can be controlled allosterically as well as through reversible covalent modification
Pregunta 16
Pregunta
Which of the following is TRUE?
Respuesta
-
the main regulative enzyme in glycolysis is phosphofructokinase 1
-
the main regulative enzyme in glycolysis is glyceraldehyde-1-phosphate dehydrogenase
-
hexokinase involved in glycolysis is regulated by product of the reaction- glucose-6-phosphate
-
pyruvate kinase involved in glycolysis is regulated by covalent modification (reversible phosphorylation/ dephosphorylation) only in the liver
-
pyruvate kinase involved in glycolysis is regulated by covalent modification (reversible phosphorylation/ dephosphorylation) only in the tissues
Pregunta 17
Pregunta
By which of the following fatty acids derive carbon atoms for the gluconeogenesis?
Respuesta
-
citrate
-
propionate
-
pyruvate
-
lactate
-
acetyl-COA
Pregunta 18
Pregunta
Which are the common metabolites for glycolysis and pentose phosphate pathway?
Respuesta
-
Erythrose-4-phosphate
-
Fructose-1,6-bisphosphate
-
Glucose-6-phosphate
-
Glyceraldehyde-3-phosphate
-
Dihydroxyacetone phosphate
-
Fructose-6-phosphate
-
Pyruvate
Pregunta 19
Pregunta
Which of the following statements about glycogen degradation in liver are true?
Respuesta
-
The regulatory enzyme is glycogen phophorylase
-
The regulatory enzyme is debranching enzyme
-
The regulatory enzyme is activated by ATP and glucose-6-phosphate
-
It is a source of energy for the liver itself
-
It is most fast activated mechanism for maintenance of blood glucose level in periods of fasting
-
The degradation stops till glucose-6-phosphate
Pregunta 20
Pregunta
Which of the following statements about fructose are true?
Respuesta
-
It is absorbed mainly through GLUT5
-
Can be metabolized in muscles by fructokinase and enter glycolysis in one step
-
Can be metabolized in liver, skeletal muscles, spermatozoa and other extrahepatic tissues but by different enzymes
-
A deficiency in aldolase B causes fructose intolerance
-
In liver fructose enters glycolysis at the level of trioses-glyceraldehyde-3-phosphate and dihydroxyacetone phosphate
Pregunta 21
Pregunta
In which of the following pathways does UDP participate?
Pregunta 22
Pregunta
Glucagon secretion increases:
Pregunta 23
Pregunta
Which of the following is TRUE?
Respuesta
-
liver glycogen stores and exports glucose to maintain blood glucose
-
liver and muscles lack glucose-6-phospatase
-
the synthesis of glycogen is initiated by the formation of glycogen primer
-
the cleavage of glycogen by glycogen phosphorylase yields UDPGlc
Pregunta 24
Pregunta
Which of the following is TRUE
Respuesta
-
glycogen phosphorylase is active phosphorylated
-
hormones like glucagon and adrenaline increase glycogenolysis
-
a rise in cAMP concentration activates glycogen synthase
-
insulin increases glycogenolysis
Pregunta 25
Pregunta
Which are the major precursors for glucose production via gluconeogenesis?
Respuesta
-
lactate
-
glucogenic amino acids
-
glycerol
-
fructose
-
acetyl-CoA
Pregunta 26
Pregunta
Which of the following about pentose phosphate pathway (PPP) is TRUE?
Respuesta
-
it generates NADPH for reductive biosynthesis
-
it generates ribose phosphate for nucleotide and nucleic acids formation
-
the enzymes of PPP are mitochondrial
-
PPP protects the erythrocytes against hemolysis
Pregunta 27
Pregunta
Which of the following is TRUE?
Respuesta
-
citrate and ATP are allosteric inhibitors of phosphofructokinase-1
-
fructose-2,6-bisphosphate is an allosteric activator of phosphofructokinase-1
-
phosphofructokinase-1 activity is increased by insulin
-
phosphofructokinase-1 activity is increased by glucagon
Pregunta 28
Pregunta
Which of the following enzymes participate in glycolysis?
Respuesta
-
Hexokinase
-
Glucose-6-phosphatase
-
Phosphofructokinase
-
Pyruvate kinase
-
PEP carboxykinase
Pregunta 29
Pregunta
What 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)?
Pregunta 30
Pregunta
Insulin stimulates:
Respuesta
-
glycolysis
-
lipolysis
-
gluconeogenesis
-
glycogen degradation
-
glycogen synthesis
Pregunta 31
Pregunta
Which of the following statements about pentose phosphate pathway are true?
Respuesta
-
It is the major donor of NADH+H+
-
It is the major donor of NADPH+H+
-
It is located in the mitochondria
-
Its major goal is generation of energy
-
it produces reducing agents for various synthesis but also ribose for nucleic acids formation
Pregunta 32
Pregunta
Which are the regulatory enzymes in gluconeogenesis?
Pregunta 33
Respuesta
-
ls metabolized both in liver and extrahepatic tissues
-
Is metabolized only in liver
-
Its metabolism requires UDP
-
Can be used for maintenance of blood glucose level
-
Galactosemia type I (classical) is caused by deficiency in galactokinase
Pregunta 34
Pregunta
Which of the following statements about carbohydrate metabolism in red blood cells are true?
Respuesta
-
Glycolysis can be performed either in aerobic or anaerobic conditions
-
The terminal product of glycolysis is always lactate
-
RBC contain smaller amounts of 2,3 bisphosphoglycerate compared the rest of the cells
-
Pentose phosphate pathway is of vital importance for the RBC
-
RBC participate in Cori Cycle
Pregunta 35
Pregunta
Which of the following is TRUE?
Respuesta
-
all of the enzymes of glycolysis are in the cytosol
-
glucokinase is an isoenzyme of hexokinase in liver and pancreatic β-cells
-
phosphofructokinase-1 is a major regulatory enzyme of glycolysis
-
glycolyis is a pathway that can function only aerobically
Pregunta 36
Respuesta
-
ls a branched polymer composed only of glucose residues
-
The main regulatory enzyme of its synthesis - glycogen synthase, is activated by epinephrine
-
ls present most prominently in liver and muscle cells but has different function in them
-
The regulatory enzymes both in synthesis and degradation can be controlled allosterically as well as through reversible covalent modification
-
α-(1->6) glycosidic bond cleavage is executed by glycogen phosphorylase
Pregunta 37
Pregunta
Which of the following statements about insulin and glucagon are true?
Respuesta
-
Insulin is secreted in response to hyperglycemia
-
Insulin is secreted in response to hypoglycemia
-
Glucagon is activator of gluconeogenesis and glycogen degradation
-
Insulin inhibits pentose phosphate pathway
-
Insulin activates phosphofructokinase 1 and thus glycolysis
Pregunta 38
Pregunta
Which of the following statements about regulation of carbohydrate metabolism are true?
Respuesta
-
Fructose-2,6-bisphosphate is aIIosteric activator of glycoiysis and inhibitor of giuconeogenesis
-
Fructose-2,6-bisphosphate is allosteric inhibitor of glycoiysis and activator of giuconeogenesis
-
ATP and citrate are inhibitors of glycolysis
-
AMP is an activator of glycoiysis
Pregunta 39
Pregunta
Which of the following statements are true?
Respuesta
-
Deficiency in glucose-6-phosphate dehydrogenase may cause haemolytic anaemia
-
Fructose is metabolized only in liver
-
Fructosuria is caused by deficiency in fructokinase
-
Glucose is transported in liver and pancreas through GLUT 3
Pregunta 40
Pregunta
Which of the following statements about regulation of glycolysis are TRUE?
Respuesta
-
Hexokinase is not a regulatory enzyme
-
Glucokinase is not inhibited allosterically by glucose-6-phosphate
-
Phosphofructokinase 1 is the most important regulatory enzyme
-
Fructose-2,6-bisphosphate activates glycolysis
-
Insulin causes a decrease in the concentration of fructose-2,6-bisphosphate
Pregunta 41
Pregunta
Which of the following is TRUE?
Respuesta
-
glycogen phosphorylase is active dephosphorylated
-
hormones like glucagon and adrenaline increase glycogen synthesis
-
a rise in cAMP concentration activates glycogen phosphorylase
-
insulin increases glycogen synthesis
Pregunta 42
Pregunta
How 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?