Carbohydrate Metabolism.pdf

Carbohydrate Metabolism: MCQ on Glycolysis & Gluconeogenesis 1) Which of the following enzyme is not involved in galactose metabolism? a) Glucokinase b) Galactokinase c) Galactose-1-Phosphate Uridyl transferase d) UDP-Galactose 4- epimerase 2) Which of the following enzyme is defective i...

Carbohydrate Metabolism: MCQ on Glycolysis & Gluconeogenesis 1) Which of the following enzyme is not involved in galactose metabolism? a) Glucokinase b) Galactokinase c) Galactose-1-Phosphate Uridyl transferase d) UDP-Galactose 4- epimerase 2) Which of the following enzyme is defective in galactosemia- a fatal genetic disorder in infants? a) Glucokinase b) Galactokinase c) Galactose-1-Phosphate Uridyl transferase d) UDP-Galactose 4- epimerase 3) In the liver, the accumulation of which of the following metabolite attenuates the inhibitory of ATP on phosphofructokinase? a) Glucose-6-Phosphate b) Citrate c) Fructose-1,6-Bisphosphate d) Fructose-2,6-Bisphosphate 4) Mutation in which of the following enzymes leads to a glycogen storage disease known as Tarui’s disease? a) Glucokinase b)Phosphofructokinase c) Phosphoglucomutase d) Pyruvate Kinase 5) Erythrocytes undergo glycolysis for the production of ATP. The deficiency of ……………........ enzyme leads to hemolytic anemia? a) Glucokinase b)Phosphofructokinase c) Phosphoglucomutase d) Pyruvate Kinase 6) Cancer cells have high energy demands for replication and division. Increased flux of glucose into glycolysis replenishes the energy demand. Which of the following enzyme plays an important role in tumor metabolism? a) Glucokinase b)Phosphofructokinase c) Phosphoglucomutase d) Pyruvate Kinase M2 7) Which of the following glucose transporter (GLUT) is important in insulin- dependent glucose uptake? a) GLUT1 b) GLUT2 c) GLUT3 d) GLUT4 8) Which of the following glucose transporter (GLUT) is present in the beta cells of the pancreas? a) GLUT1 b) GLUT2 c) GLUT3 d) GLUT4 9) Which of the following glucose transporter (GLUT) is important in fructose transport in the intestine? a) GLUT1 b) GLUT3 c) GLUT5 d) GLUT7 10) Which of the following metabolite negatively regulates pyruvate kinase? a) Fructose-1,6-Bisphosphate b) Citrate c) Acetyl CoA d) Alanine 11) In absence of oxygen, pyruvate is converted into lactate in muscle because a) Lactate is the substrate from the downstream pathway b) Lactate acts as a substrate for the formation of amino acid c) during the product of lactate two ATP are produced d) during lactate formation, NADH is reconverted into NAD. 12) Which of the following glycolytic enzyme is inhibited by the accumulation of long-chain fatty acid in the liver? a) Hexokinase b) Glucokinase c)Phosphofructokinase d) Pyruvate kinase 13) Which of the following statement related to phosphofructokinase-I is false: a) PFK-2 is the isoenzyme of PFK-1 that is present in the liver b) PFK-1 is activated by AMP whereas inhibited by ATP and citrate c) The binding of ATP to PFK-1 induces the conformation change from R to T state d) PFK-1 is regulated by posttranslational modification such as phosphorylation 14) Which of the following statement about Phosphofructokinase-2 (PFK-2) is false? a) PFK-2 is a bifunctional enzyme having a kinase domain, phosphatase domain, and a regulatory domain b) Activated protein kinase A phosphorylates PFK-2 and activates the phosphatase domain c) PFK-2 catalyzes the conversion of fructose-6-phosphate to fructose 2-6 bisphosphate d) PFK-2 phosphatase activity is activated by the insulin signaling pathway. 15) Which of the following hormone decreases blood glucose and increases the uptake of glucose in various tissues like skeletal muscle, and adipose tissues? a) Glucagon b) Epinephrine c) Cortisol d) Insulin 16) Which of the following statement is true? a) Glycolysis occurs only in mammalian cells b) Glycolysis occurs in mitochondria c) Glycolysis occurs in the presence and absence of oxygen d) Glycolysis occurs when ATP concentration is high. 17) What is the rate-limiting step in glycolysis? a) Hexokinase b) Phosphohexose isomerase c) Glyceraldehyde-3-phosphate dehydrogenase d) Enolase 18) The net gain of ATP during the conversion of glucose to pyruvate is: a) 1 ATP b) 2 ATP c) 1 ATP +1 GTP d) 4 ATP 19) During the conversion of glucose to pyruvate, two NADH molecules are generated. Which of the following steps generates NADH? a) Conversion of fructose-6-phosphate to fructose-1-6-bisphosphate b) Conversion of glyceraldehydes-3-phosphate to 1-3-bisphosphoglycerate c)Conversion of 3-phosphoglycerate to 2-phosphoglycerate d) Conversion of phosphoenolpyruvate to pyruvate 20) What is the committed step in glycolysis? a) Conversion of glucose to glucose-6-phosphate b) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate c) Conversion of glyceraldehydes-3-phosphate to 1-3-bisphosphoglycerate d) Conversion of 3-phosphoglycerate to 2-phosphoglycerate 21) Glycolysis consists of three irreversible steps. Which of the following enzyme-catalyzed reaction are not irreversible steps in glycolysis? a) Hexokinase b) Phosphofructokinase c) Glyceraldehyde-3-phosphate kinase d) Pyruvate kinase 22) The following are the negative regulators of phosphofructokinase except a) ATP b) AMP c) Citrate d) pH 23) Which of the following step is inhibited by sodium fluoride? a) Glyceraldehyde-3-phosphate dehydrogenase b) 3-phosphoglycerate mutase c) Enolase b) AMP 24) Which of the following step is inhibited during arsenate poisoning? a) Glyceraldehyde-3-phosphate dehydrogenase b) 3-phosphoglycerate mutase c) Enolase d) Pyruvate kinase 25)Which of the following enzyme catalyzes the conversion of pyruvate to lactate? a) Pyruvate reductase b) Lactate reductase c) Lactate dehydrogenase d) Pyruvate dehydrogenase 26) Glucokinase is an isoenzyme of hexokinase that has high Km and Vmax. Which of the following organ expresses glucokinase? a) Kidney b) Muscle c) Liver d) Brain 27) Gluconeogenesis is the production of glucose from non-carbohydrate molecules. Which of the following is not a substrate for gluconeogenesis? a) Lactate b) Alanine c) Glycerol d) Acetyl CoA 28) Gluconeogenesis occurs in the liver and kidneys. Which is of the following enzyme are important for gluconeogenesis and are expressed exclusively in these tissues? a) Glucose-6-phosphatase b) Fructose-1,6-Bisphosphatase c) Phosphoenolpyruvate carboxykinase d) Pyruvate carboxylase 29) During gluconeogenesis, the three irreversible steps of glycolysis have to be bypassed. The first step is the conversion of pyruvate to phosphoenolpyruvate. Which of the following statement is false regarding the reaction step? a) This reaction involves a two-step process catalyzed by pyruvate carboxylase and phosphoenolpyruvate carboxykinase b) Conversion of oxaloacetate from pyruvate occurs in mitochondria and shuttled into the cytosol. c) Formation of phosphoenolpyruvate requires both ATP and GTP as an energy source. d) Acetyl CoA is an activator of the enzyme pyruvate carboxylase. 30) During gluconeogenesis, the three irreversible steps of glycolysis have to be bypassed. The final step is the conversion of glucose-6-P to glucose which is catalyzed by glucose-6-phosphatase. Which of the following statement is true about the reaction step? a) Conversion of glucose-6-phosphate to glucose releases one ATP molecule b) It is a highly active enzyme in skeletal muscle c) Defect in glucose-6-phosphatase leads to abnormal accumulation of glycogen in the liver d) The reaction occurs in mitochondria 31) Which of the following statement is true about Cori Cycle? a) The Cori cycle involves three tissues muscle, liver, and brain b) It involves the transport of lactate from the liver to skeletal tissue for gluconeogenesis c) It involves the transport of lactate from skeletal muscle to the liver for gluconeogenesis d) It is active during resting stages and in well-fed condition 32) During prolong starvation, which of the following hormone is responsible for increasing gluconeogenesis in the liver a) Insulin b) Glucagon c) TSH d) Thyroxine Answers: 1-a) Glucokinase 2-c) Galactose-1-Phosphate Uridyl transferase 3-d) Fructose-2,6-Bisphosphate 4-b)Phosphofructokinase. 5- d) Pyruvate Kinase 6- d) Pyruvate Kinase M2 7- d) GLUT4 8- b) GLUT2 9- c) GLUT5 10- d) Alanine 11- d) during lactate formation, NADH is reconverted into NAD 12- b) Glucokinase 13- d) PFK-1 is regulated by posttranslational modification such as phosphorylation 14- b) Activated protein kinase A phosphorylates PFK-2 and activates the phosphatase domain 15-d) Insulin 16-c) Glycolysis occurs in the presence and absence of oxygen 17- a) Hexokinase 18- b) 2 ATP 19- b) Conversion of glyceraldehydes-3-phosphate to 1-3- bisphosphoglycerate 20- b) Conversion of fructose-6-phosphate to fructose-1,6-bisphosphate 21- c) Glyceraldehyde-3-phosphate kinase 22-b) AMP 23- c) Enolase 24-a) Glyceraldehyde-3-phosphate dehydrogenase 25- c) Lactate dehydrogenase 26-c) Liver 27-d) Acetyl CoA 28- a) Glucose-6-phosphatase 29-d) Acetyl CoA is an activator of enzyme pyruvate carboxylase 30- c) Defect in glucose-6-phosphatase leads to abnormal accumulation of glycogen in the liver 31-c) It involves the transport of lactate from skeletal muscle to the liver for gluconeogenesis 32-b) Glucagon