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Home , Galactokinase, Glucogenic amino acid, Gluconeogenesis, Glycogenesis, Glycogenolysis, Glycolysis

GPAT ONLINE CLASSES DAY 21

BY

V.JAGAN MOHAN RAO M.S.Pharm., MED.CHEM NIPER-KOLKATA Asst. Professor, MIPER-KURNOOL EMAIL- jaganvana6gmail.com

INTRODUCTION TO

BIOCHEMISTRY

 CHEMICAL ORGANIZATION OF

 SYNTHESIS & ROLE OF ATP

CARBOHYDRATE CLASSIFICATION  Vs RESPIRATION  OVERVIEW –  KREB’S CYCLE  ETC ()

CARBOHYDRATE METABOLISM 1. Name the pathway for synthesis by non-carbohydrate precursors? a) b) Glycolysis c) d)

Answer: c Explanation: Synthesis of glucose from non-carbohydrate sources is carried out by gluconeogenesis. It is the universal pathway, found in all , , and .

2. What is the site for gluconeogenesis? a) b) Blood c) Muscles d) Brain

Answer: a Explanation: Gluconeogenesis in animals takes place in the liver as well as some extent in the cortex. The kidney is capable of making glucose during the condition of and can make up to 50% of glucose.

3. Which of the following is not the precursor of gluconeogenesis? a) Glycolytic products b) cycle intermediates c) Glucogenic d) or

Answer: d Explanation: Only leucine or lysine is the which is not used for gluconeogenesis as these amino acids produce only acetyl-CoA upon degradation. Animals cannot carry out gluconeogenesis by two acetyl carbon of acetyl-CoA.

4. Name the which is responsible for the conversion of pyruvate to phosphoenolpyruvate (PEP)? a) b) Pyruvate carboxykinase c) Glucose 6- d)

Answer: b Explanation: The conversion of pyruvate to PEP takes place in two stages, the first reaction is catalyzed by pyruvate carboxylase which converts pyruvate to oxaloacetate and in second reaction oxaloacetate is converted by pyruvate carboxykinase to PEP.

5. Gluconeogenesis is also carried out in muscle and brain. a) True b) False

Answer: b Explanation: Gluconeogenesis cannot be carried out in muscle and brain as they do not have glucose 6- phosphatase enzyme which is required to convert glucose 6- to glucose. Glucose 6- phosphatase can only be established in the of kidney and liver cells.

6. Which of the following are major sites for storage? a) b) Bones c) Muscle and liver d) Kidney and liver

Answer: c Explanation: Glycogen is stored in muscle and liver only. The amount of glycogen is high in the liver but a larger amount of glycogen stored in the greater bunch of skeletal muscles. The liver uses its glycogen for the synthesis of glucose for all of the body while muscles use its glycogen for its own energy.

7. Which of the following is the precursor of glycogen? a) 3-phosphate b) Malate c) UDP-glucose d) Leucine and lysine

Answer: c Explanation: Glucose 1-phosphate and triphosphate work together to activate UDP-glucose which acts as a precursor of glycogen.

8. The priming function in glycogen synthesis is carried out by______a) Lysine b) c) d) Glutamate

Answer: c Explanation: Glycogen synthesis is carried out with the help of a primer by its priming action. Glycogenin is a primer which adds glucosyl residue in the polypeptide chain that already has more than four residues. 9. Name the enzyme which is used for branching of glycogen? a) Branching enzyme b) c) d)

Answer: a Explanation: Branching enzyme is also known as amylo-1, 4 —–> 1, 6 transglycosylase which adds a branch at four residues away from the existing branch. in Hexokinase, Phosphoglucomutase, and glycogen synthase are used in glycogen synthesis but not in branching.

10. Which of the following maintain blood glucose level by activation of gluconeogenesis? a) Nor- b) c) d) Epinephrine

Answer: b Explanation: Glucagon acts opposite to insulin, and is secreted by the α-cells of the . It maintains blood glucose level by the activation of glycogenolysis and gluconeogenesis.

11. Name the hormone which is secreted in an emergency or in condition? a) Epinephrine b) Glucagon c) Insulin d)

Answer: a Explanation: Epinephrine is also known as emergency hormone and it is secreted in the condition of stress and emergencies like injury, pain, fear, accident, and grief. It increases the level of sugar in the blood by stimulating glycogenolysis.

PRACTICE QUESTIONS

1) Which of the following enzyme is not involved in metabolism? a) b) c) Galactose-1-Phosphate Uridyl d) UDP-Galactose 4- epimerase 2) Which of the following enzyme is defective in - a fatal genetic disorder in infants? a) Glucokinase b) Galactokinase c) Galactose-1-Phosphate Uridyl transferase d) UDP-Galactose 4- epimerase 3) In liver, the accumulation of which of the following metabolite attenuates the inhibitory of ATP on Phosphofructokinase? a) Glucose-6-Phosphate b) Citrate c) -1,6-Bisphosphate d) Fructose-2,6-Bisphosphate 4) in which of the following enzymes leads to a known as Tarui’s disease? a) Glucokinase b)Phosphofructokinase c) Phosphoglucomutase d) Pyruvate 5) Erythrocytes undergo glycolysis for production of ATP. The deficiency of ……………. enzyme leads to hemolytic ? a) Glucokinase b)Phosphofructokinase c) Phosphoglucomutase d) 6) cells have high energy demands for replication and division. Increased 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 (GLUT) are 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 beta cells of the ? 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)

Answers 1- a, 2-c, 3-d, 4-b, 5-d, 6-d, 7-d, 8-b, 9-c, 10-d