Which are the regulatory enzymes in glycolysis?
Hexokinase
Glucose-6-phosphate Isomerase
Phosphofructokinase
Phosphoglycerate Mutase
Pyruvate Kinase
Which enzymes participate in pentose phosphate pathway?
Glucose-6-phosphate Dehydrogenase
Transaldolase
Transketolase
Gluconeogenesis occurs in:
Cytosol
Endoplasmic Reticulum
Mitochondria
Both Cytosol and Endoplasmic Reticulum
Cytosol, Mitochondria and Endoplasmic Reticulum
Which of the molecule is "linkage" between the citric acid cycle and gluconeogenesis?
Citrate
Isocitrate
Malate
Oxaloacetate
Succinyl-CoA
Which of the vitamins is involved in gluconeogenesis as coenzyme?
Vitamin C
Vitamin H (biotin)
Vitamin B1 (thiamine pyrophosphate)
Vitamin PP (NAD, NADH)
Vitamin B2 (FAD, FMN)
Show the energy source responsible for gluconeogenesis energy supply:
GTP and UTP
ATP and GTP
ATP and UTP
Acetyl-CoA
Glucose-6-Phosphate
Which of the following citric acid cycle intermediates, derived from α-amino acids, give carbon atoms for gluconeogenesis?
citrate
pyruvate
succinyl-CoA
α-ketoglutarate
oxaloacetate
Which of the following is true?
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
Which of the following enzymes are regulatory in gluconeogenesis:
Pyruvate carboxylase
Glucose-6-phosphatase
Pyruvate kinase
ΡΕΡ carboxykinase
Which of the following hormones stimulate gluconeogenesis:
insulin
glucagon
cortisol
adrenaline
Gluconeogenesis:
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
Which are the true statements about regulation of glycolysis?
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
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?
2
3
4
6
8
Which of the following statements about insulin and glucagon are true?
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
Glycogen:
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
Which of the following is TRUE?
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
By which of the following fatty acids derive carbon atoms for the gluconeogenesis?
propionate
lactate
acetyl-COA
Which are the common metabolites for glycolysis and pentose phosphate pathway?
Erythrose-4-phosphate
Fructose-1,6-bisphosphate
Glucose-6-phosphate
Glyceraldehyde-3-phosphate
Dihydroxyacetone phosphate
Fructose-6-phosphate
Pyruvate
Which of the following statements about glycogen degradation in liver are true?
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
Which of the following statements about fructose are true?
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
In which of the following pathways does UDP participate?
Glycolysis
Gluconeogenesis
Synthesis of glycogen
Degradation of glycogen
Galactose metabolism
Pentose phosphate pathway
Glucagon secretion increases:
at high insulin levels
at low insulin levels
at high blood glucose content
at low blood glucose content
in fasting
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
Which of the following is TRUE
glycogen phosphorylase is active phosphorylated
hormones like glucagon and adrenaline increase glycogenolysis
a rise in cAMP concentration activates glycogen synthase
insulin increases glycogenolysis
Which are the major precursors for glucose production via gluconeogenesis?
glucogenic amino acids
glycerol
fructose
acetyl-CoA
Which of the following about pentose phosphate pathway (PPP) is TRUE?
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
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
Which of the following enzymes participate in glycolysis?
PEP carboxykinase
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)?
32
38
24
12
Insulin stimulates:
glycolysis
lipolysis
gluconeogenesis
glycogen degradation
glycogen synthesis
Which of the following statements about pentose phosphate pathway are true?
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
Which are the regulatory enzymes in gluconeogenesis?
Glucokinase
Phosphoglucomutase
Phosphoenolpvruvate carboxykinase
Fructose-1,6-bisphosphatase
Galactose:
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
Which of the following statements about carbohydrate metabolism in red blood cells are true?
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
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
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
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
Which of the following statements about regulation of carbohydrate metabolism are true?
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
Which of the following statements are true?
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
Which of the following statements about regulation of glycolysis are TRUE?
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
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?
5
