Previous year question on glycolysis based on neet pg, usmle, plab and fmge or mci screening exams

The phenomenon of cancer cells switching to glycolysis even in the presence of adequate oxygen for oxidative phosphorylation is known as:

A: Tyndall effectB: Warburg effectC: Hawthorne effectD: None of the aboveCorrect Ans:BExplanationEven in the presence of ample oxygen, cancer cells shift their glucose metabolism away from the oxygen hungry, but efficient, mitochondria to glycolysis. This phenomenon, called the Warburg effect and also known as aerobic glycolysis, has been recognized for many years (indeed, Otto Warburg received the Nobel Prize for discovery of the effect that bears his name in 1931), but was largely neglected until recently. This metabolic alteration is so common to tumors that some would call it the eighth hallmark of cancer. Ref: Robbins 8th edition Chapter 2.

Sample Previous Year Question on Glycolysis based on previous Year Questions of NEET PG, USMLE,PLAB,FMGE (MCI Screening). Please visit www.medicoapps.org for more such Quizzes

What is the net amount of ATP's formed in aerobic glycolysis?

A: 5B: 8

C: 10D: 15Correct Ans:BExplanationDuring aerobic glycolysis the number of net ATPs formed are 8.Steps involved in the formation of ATP during glycolysis are:

Conversion of 2 molecules of glyceraldehyde 3 phosphate to 1,3 bisphoglycerate release 2 molecules of NADH which yield 6 ATP.

Conversion of 2 molecules of 1,3 BPG to 3 phosphoglycerate yield 2 ATP. Conversion of 2 molecules of phosphoenol pyruvate to pyruvate yield 2

ATP.

Steps involved in the consumption of ATP during glycolysis are:

Conversion of glucose to glucose 6 phosphate Conversion of fructose 6 phosphate to fructose 6 bis phosphate

Total ATP formed during glycolysis : 10 ATP utilised during glycolysis : 2 Net ATP formed during glycolysis : 8

Net ATP produced during anaerobic glycolysis is only 2.

Ref: Medical Biochemistry By N. Mallikarjuna Rao page 160.


Net ATP's formed in glycolysis are:

A: 5B: 8

C: 10D: 15Correct Ans:BExplanationAerobic glycolysis is a process of splitting of glucose into two molecules of pyruvate with the synthesis of ATP. Net ATP formed in aerobic glycolysis is 8.

Glycolysis: is the process by which glucose or other hexoses are converted into the three-carbon compound pyruvate. All the reactions takes place in cytoplasm.

Aerobic glycolysis: is a process of splitting of glucose into two molecules of pyruvate with the synthesis of ATP.

Anaerobic Glycolysis: glycolysis is the only process in which ATP is generated anaerobically. This is of importance because RBC which does not have a mitochondria is wholly dependant on the anaerobic energy production. The byproduct of anaerobic glycolysis is lactate.

Glycolytic pathway: occurs in cytoplasm consists of 10 steps. The first five steps result in one molecule of glucose is converted to 2 glyceraldehyde-3-phosphate molecules at the expense of two molecules of ATPs. The second five steps results in the production of 2 ATP molecules per one molecule of glucose.

Rate limiting step: Phosphofructokinase the commited step of glycolysis. Irreversibles steps:

Hexokinase or glucokinase Phosphofructokinase Pyruvate kinase

No of ATP generated is:Aerobic glycolysis 8Anaerobic glycolysis 2

Enzyme Reducing Equivalents

Glucokinase

Phosphofructokinase

Glyceraldehyde 3 phosphate dehydrogenase 2 NADH

Phosphoglycerate kinase

Pyruvate kinase

NET ATP

Ref: Essentials of Medical Biochemistry: With Clinical Cases, By Chung-Eun Ha, N. V. Bhagavan, Page 115


Which of the following reaction produces CO2?

A: Amino acid synthesisB: HMP shunt pathway

C: GlycolysisD: None of the aboveCorrect Ans:BExplanationInpentose phosphate pathway (hexose monophosphate shunt) three molecules of glucose 6-phosphate give rise to three molecules of CO2 and three 5-carbon sugars. These are rearranged to regenerate two molecules of glucose 6-phosphate and one molecule of the glycolytic intermediate, glyceraldehyde 3-phosphate.

Ref: Bender D.A., Mayes P.A. (2011). Chapter 21. The Pentose Phosphate Pathway & Other Pathways of Hexose Metabolism. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.


What is the net ATP's formed in glycolysis?

A: 5B: 7

C: 10D: 15Correct Ans:BExplanation

ATP formation in glycolysis:

Reaction Catalyzed by Method of ATP Formation

Glyceraldehyde 3-phosphate dehydrogenase Respiratory chain oxidation of 2 NADH

Phosphoglycerate kinase Substrate-level phosphorylation

Pyruvate kinase Substrate-level phosphorylation

Consumption of ATP for reactions of hexokinase and phosphofructokinase

Ref: Bender D.A., Mayes P.A. (2011). Chapter 18. Glycolysis & the Oxidation of Pyruvate. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.


Which of the following statements about anaerobic glycolysis is INCORRECT?

A: Anaerobic glycolysis yields two molecules of lactate and two molecules of ATP

B:There are two oxidation-reduction steps in the anaerobic glycolysis.

C:The lactated formed in the muscles in the condition of an oxygen deficit can be recycled through the Cori cycle.

D:The extraction of energy from the molecule of glucose in the anaerobic glycolysis happens due to the net change in the oxidation state of carbon

Correct Ans:DExplanation

Although there are two oxidation-reduction steps is the anaerobic glycolysis, and the energy for the synthesis of two ATP molecules is released, there is no net change in the oxidation state of carbon. The first oxidative reaction is catalyzed by glyceraldehyde-3-phosphate dehydrogenase to yield NADH. Later, NADH is spent for the reduction of pyruvate to the lactate which is catalyzed by lactate dehydrogenase. The ratio between C, H, and O atoms is the same for both glucose, C6H12O6 and lactic acid C3H6O3.



Which of the following occurs during glycolysis?

A: Glucose is reduced to pyruvate in the cytosol of all cells.B: The rate-limiting step is the formation of fructose-6-phosphate.C: Glucose is phosphorylated by aldolase.D: Pyruvate, NADH, and ATP are produced.Correct Ans:DExplanation

In virtually all cells of the body, glycolysis is the primary pathway for carbohydrate catabolism. During glycolysis, glucose undergoes oxidation to form pyruvate, NADH, and ATP. The initial reaction of glycolysis involves phosphorylation of glucose to glucose-6-phosphate via the enzyme hexokinase (glucokinase in liver). The first committed step involves the phosphorylation of fructose-6-phosphate to fructose-1,6-diphosphate by phosphofructokinase (PFK). The reactions catalyzed by hexokinase and PFK are two of three irreversible reactions occurring in glycolysis. The other irreversible reaction involves pyruvate kinase. In terms of the energetics of the reactants and products, it is important to remember that every intermediate in this pathway between glucose and pyruvate contains phosphate.



Which of the following metabolic pathways does not generate ATP:

A: GlycolysisB: TCA CycleC: Fatty Acid OxidationD: HMP Pathway


No ATP is directly consumed or produced in the hexose monophosphate shunt (HMP).

Ref: Harper’s Textbook of Biochemistry, 27th Edition, Pages 177, 189; Lippincott’s Biochemistry, 5th Edition, Pages 104, 113, 145, 192


Within the RBC, hypoxia stimulates glycolysis by which of the following regulating pathways?

A: Hypoxia stimulates pyruvate dehydrogenase by increased 2,3 DPGB: Hypoxia inhibits hexokinaseC: Hypoxia stimulates release of all glycolytic enzymes from band 3 on RBC membraneD: Activation of the regulatory enzymes by high PH

Correct Ans:CExplanationDuring Hypoxia, the glycolytic enzymes that bind in the same region of band 3 of Hb are released from the membrane resulting in an increased rate of glycolysis. Increased glycolysis increases ATP production and the hypoxic release of ATP.

Ref: Oxygen Transport to Tissue, Xxxiii, edited by Martin Wolf, David K Harrison, 2012, Page 188.


Which is the following is associated with the malate shuttle?

A: GlycolysisB: GluconeogenesisC: GlycogenolysisD: Ketone body synthesisCorrect Ans:AExplanation

Malate shuttleis a biochemical system for translocating electrons produced during glycolysis across the semi permeable inner membrane of the mitochondrion for oxidative phosphorylation. These electrons enter the electron transport chain of the mitochondria via

reduction equivalents to generate ATP.

The NADPH produced in glycolysis is transported into the mitochondria with the help of Malate shuttle to liberate 3 ATP molecules.


During uncontrolled diabetes, one of the factors producing hyperglycemia is gluconeogenesis. Which statement about gluconeogenesis is correct?

A: Acetyl-CoA is used for the net synthesis of glucoseB: It occurs primarily in skeletal muscleC: It occur through reversal of the reactions of glycolysisD: Lactate and alanine can both serve as substrates


Lactate and alanine are both converted to pyruvate to enter the gluconeogenic pathway.


Which of the following is FALSE about insulin action?

A: Glycogen synthesisB: Glycolysis

C: LipognesisD: KetogenesisCorrect Ans:DExplanation

Insulin inhibits lipolysis by inhibiting hormone sensitive lipase. Thus insulin prevents ketogenesis.

Insulin stimulates glycolysis by activating PFK-1 Insulin activates glycogenesis by activating glycogen synthase. Also it stimulates fatty acid synthesis by activating acetyl Co A

carboxylase.

Insulin also—by its ability to depress the level of intracellular cAMP—inhibits lipolysis in adipose tissue reducing the concentration of plasma-free fatty acids and, therefore, long-chain acyl-CoA, which are inhibitors of lipogenesis.

Ref: Botham K.M., Mayes P.A. (2011). Chapter 23. Biosynthesis of Fatty Acids & Eicosanoids. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e


Phosphofructokinase-1 occupies a key position in regulating glycolysis and is also subjected to feedback control. Which among the following is the allosteric activators of phosphofructokinase-1?

A: Fructose 2, 3 bisphosphateB: Fructose 2, 6 bisphosphateC: GlucokinaseD: PEP

Correct Ans:BExplanation

The most potent positive allosteric activator of phosphofructokinase-1 and inhibitor of fructose 1,6-bisphosphatase in the liver is fructose 2,6-bisphosphate.

It relieves inhibition of phosphofructokinase-1 by ATP and increases the affinity for fructose 6-phosphate.

It inhibits fructose 1,6-bisphosphatase by increasing the Km for fructose 1,6-bisphosphate.

Its concentration is under both substrate (allosteric) and hormonal control (covalent modification).

Phosphofructokinase-1 is inhibited by citrate and by normal intracellular concentrations of ATP and is activated by 5' AMP.

Ref: Bender D.A., Mayes P.A. (2011). Chapter 20. Gluconeogenesis & the Control of Blood Glucose. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.


Glycolysis is the metabolic pathway that involves 10 enzyme mediated steps. It occur in which of the following cell organelle?

A: CytosolB: MitochondriaC: NucleusD: LysosomeCorrect Ans:AExplanation

Glycolysis, the major pathway for glucose metabolism, occurs in the cytosol of all cells. Glycolysis is both the principal route for glucose metabolism and also the main pathway for the metabolism of fructose, galactose, and other dietary carbohydrates.



Enzymes of glycolysis are found in:

A: CytosolB: Cell membraneC: MitochondriaD: Ribososmes

Correct Ans:AExplanationAll of the enzymes of glycolysis are found in the cytosol. Ref: Harper 28th edition, chapter 18.


Common to both glycolysis and pentose phosphate pathway is:

A: Glucose 6 phosphateB: NAD

C: ATPD: All of the aboveCorrect Ans:AExplanationAlthough glucose 6-phosphate is common to both pathways, the pentose phosphate pathway is markedly different from glycolysis. Oxidation utilizes NADP rather than NAD, and CO2, which is not produced in glycolysis, is a characteristic product. No ATP is generated in the pentose phosphate pathway, whereas it is a major product of glycolysis

Ref: Harper 28th edition, chapter 21.


A 19-year-old athlete has been vigorously working on the tracks and begins to feel slightly light-headed from hypoglycemia. He drinks a can of soft drinks and is aware of the

competition for the glucose to be stored in his liver as glycogen versus used as energy in his muscles. What is the best explanation regarding the fate of the glucose in the soft drink?

A:The lower Km of hexokinase versus the Km of glucokinase will tilt the glucose toward glycolysis.

B:The bolus of glucose via the soda will lead to a higher glucose level, inducing storage of the glucose into glycogen in the liver.

C:The muscle is using high levels of glucose, leading to an increased level of glucose 6-phosphate thus inhibiting glucokinase.

D: The glucose will be equally used by muscle for metabolism and liver for glycogen storage.

Correct Ans:AExplanationThe Michaelis constant (Km) is a means of characterising an enzyme's affinity for a substrate. The Km in an enzymatic reaction is the substrate concentration at which the reaction rate is half its maximum speed. Thus, a low Km value means that the enzyme has a high affinity for the substrate (as a "little" substrate is enough to run the reaction at half its max speed).

Hexokinase has a low Km for glucose, and in the liver is saturated and acting at a constant rate under all normal conditions. Glucokinase has a considerably higher Km (lower affinity) for glucose, so that its activity increases with increases in the concentration of glucose in the hepatic portal vein. It promotes hepatic uptake of large amounts of glucose after a carbohydrate meal. It is absent from the liver of ruminants, which have little glucose entering the portal circulation from the intestines.

Hexokinase is inhibited by glucose 6-phosphate and is most active with low levels of glucose 6-phosphate. Glucokinase found in the liver has a high Km for glucose and is very active after a meal. The glucose in the soft drink would likely be used for ATP production. At normal systemic-blood glucose concentrations (4.5–5.5 mmol/L), the liver is a net producer of glucose. However, as the glucose level rises, the output of glucose ceases, and there is a net uptake.



A patient is found to have a rare disease in which the secretory function of the alpha-cells of the pancreas is impaired. Direct stimulation of which of the following pathways in liver will be impaired?

A: Citric acid cycleB: GlycogenesisC: Gluconeogenesis

D: Glycolysis

Correct Ans:CExplanation

Gluconeogenesis is the process of synthesizing glucose or glycogen from noncarbohydrate precursors. The major substrates are the glucogenic amino acids, lactate, glycerol, and propionate. Liver and kidney are the major gluconeogenic tissues; the kidney may contribute up to 40% of total glucose synthesis in the fasting state and more in starvation.

Glucagon is a hormone produced and secreted by the alpha-cells of the pancreas in response to decreases in blood glucose.Glucagon and epinephrine, hormones that are responsive to a decrease in blood glucose, inhibit glycolysis and stimulate gluconeogenesis in the liver by increasing the concentration of cAMP. Pentose pathway and citric acid cycle are not directly affected by glucagon.



Which of the following is an energy-requiring step of glycolysis?

A: Pyruvate carboxylaseB: Phosphoenolpyruvate carboxykinaseC: Phosphoglycerate kinaseD: Hexokinase


Hexokinase catalyzes the conversion of glucose to glucose-6-phosphate in the energy-requiring first step of glycolysis. ATP is also required in the conversion of fructose-6-phosphate to fructose 1,6-bisphosphate by PFK. ATP is generated in the conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate by phosphoglycerate kinase and in the conversion of phosphoenolpyruvate to pyruvate by PK. Both phosphoenolpyruvate carboxykinase and pyruvate carboxylase are energy-requiring reactions except that these occur in the gluconeogenesis pathway.



In all of these pathways ATP is produced, EXCEPT:

A: Urea cycleB: Electron transport chainC: TCA cycleD: Anaerobic glycolysisCorrect Ans:AExplanationThe urea cycle utilises 4 ATPs. 2 ATPs are needed to make carbamoyl phosphate, one is needed to make argininosuccinate and one is needed to restore AMP to ATP. Thus urea cycle does not produce ATP it only utilises ATP.

The net yield of ATP from anaerobic glycolysis is 2. TCA cycle generate 3 NADH2, 2 FADH2 and 1 GTP. Hence, each TCA cycle yields 12 ATP molecules. As two acetyl CoA molecules are generated from each glucose this cycle occur twice yielding 24 ATP molecules.

Complete oxidation of glucose via glycolysis, pyruvate dehydrogenase, Krebs cycle, and the oxidative phosphorylation pathway yields 38 ATP. Since two ATPs were used during stage I reactions of glycolysis the net yield is 36 ATP.

Ref: Textbook of Medical Biochemistry,3e By Dinesh Puri PAGE 175. Essentials of Biochemistry By Pankaja Naik Page 233.


Although glycolysis and the pentose phosphate pathway have several common metabolites, they are markedly different otherwise. All of the following statements are true, EXCEPT:

A: CO2 is produced in the pentose phosphate pathway, but not in glycolysis.B: ATP is generated in glycolysis, but not in the pentose phosphate pathway.C: Mg2+ ions are required for both glycolysis and the pentose phosphate pathway.D: Thiamine is used as a coenzyme in both glycolysis and the pentose phosphate pathway

Correct Ans:D

Explanation

The two major pathways of catabolism of glucose, glycolysis and the pentose phosphate pathway, having several common metabolites (as for example, glucose 6-phosphate and glyceraldehyde 3-phosphate) markedly differ in many other features.CO2 is produced in the pentose phosphate pathway but not in glycolysis; Mg2+ ions are required for both glycolysis (for the phosphorylation of glucose by glucokinase) and the pentose phosphate pathway (for the functioning of transketolase and several other enzymes). Thiamine is used only in the pentose phosphate pathway (in the form of thiamine pyrophosphate as the coenzyme of transketolase). Thiamine-dependent enzymes are not involved in glycolysis taking part on later stages when pyruvate is either converted to acetyl CoA by pyruvate dehydrogenase or (in microorganisms) is reduced to ethanol by pyruvate decarboxylase.

Ref: Bender D.A., Mayes P.A. (2011). Chapter 21. The Pentose Phosphate Pathway & Other Pathways of Hexose Metabolism. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.


In glycolysis, the following forms as the byproduct:

A: PyruvateB: H2O

C: H+D: All of the aboveCorrect Ans:DExplanationGlycolysis is the metabolic pathway that breaks down (catabolism) hexose (six-carbon) monosaccharides such as glucose, fructose, and galactose into two molecules of pyruvate, two molecules of ATP, two molecules of NADH, two water (H2O) molecules, and two hydrogen ions (H+). Ref: Janson L.W., Tischler M.E. (2012). Chapter 6. Carbohydrate Metabolism. In L.W. Janson, M.E. Tischler (Eds), The Big Picture: Medical Biochemistry.


Which of the following pathway serve as the MOST important source of reducing equivalents for fatty acid synthesis in the liver?

A: GlycolysisB: TCA cycleC: Uronic acid pathwayD: HMP pathway


The co enzyme used for the de novo fatty acid synthesis is NADPH. The hexose monophosphate pathway provides a major portion of cell's NADPH for fatty acid synthesis. Tissues having active lipogenesis such as liver, adipose tissue and lactating mammary gland have an active HMP shunt pathway also.

The net reaction of de novo fatty acid synthesis can be summarized as:1 Acetyl CoA + 7 Malonyl CoA + 14 NADPH + 14H+ → 1 Palmitate + 7 CO2 + 14 NADP+ +8CoA+ + 6H2O.

The pentose phosphate pathway is an alternative route for the metabolism of glucose. The two major functions of this pathway are:

The formation of NADPH for synthesis of fatty acids and steroids, and maintaining reduced glutathione for antioxidant activity.

The synthesis of ribose for nucleotide and nucleic acid formation.

Ref: Textbook Of Biochemistry For Dental Students By Vasudevan page 104. Harper's Illustrated Biochemistry, 29e chapter 21.


What is the major role of 2, 3 bisphosphoglycerate in RBCs?

A: Acid-base balanceB: Reversal of glycolysisC: Release of oxygenD: Binding of oxygenCorrect Ans:CExplanation

2,3 BPG is responsible for significantly lowering the oxygen affinity of hemoglobin and and allowing the hemoglobin to more efficiently release oxygen at the typical Po2 of

tissues. Only one molecule of 2,3 BPG interact with each hemoglobin tetramer.

Rise in 2,3 BPG in RBCs promotes the shift of hemoglobin to the T form and subsequently release oxygen. In rbcs 2, 3 BPG rise as they adapt to conditions of tissue hypoxia ( from anemia, high altitude, pulmonary dysfunction).


A 12-year-old boy is being investigated for haemolytic anaemia.

Assertion: Pyruvate kinase is the most common enzyme deficient in hemolytic anemia.

Reason: Most common enzyme to be deficient in glycolysis is Pyruvate kinase.

A: Both Assertion and Reason are true, and Reason is the correct explanation for Assertion

B:Both Assertion and Reason are true, and Reason is not the correct explanation for Assertion

C: Assertion is true, but Reason is falseD: Assertion is false, but Reason is trueCorrect Ans:DExplanation

Glucose 6 phosphate is the most common enzyme deficient in hemolytic anemia. Most common enzyme to be deficient in glycolysis is the pyruvate kinase.


Which of the following is the source of nutrition for the cancer cells?

A: GlycolysisB: Oxidative phosphorylationC: Increase in mitochondriaD: From a fast food joint

Correct Ans:AExplanationCancer cells exhibit a high rate of aerobic glycolysis. Cancer cells take up large amounts of glucose and metabolize it to lactic acid, even in the presence of oxygen (the so-called Warburg effect). It is due to a defect in the respiratory chain, so that tumor cells compensated for this by producing more ATP via glycolysis. Tumor cells have less mitochondria than normal cells and they contain a mitochondrial-bound isozyme of hexokinase (HK-2) that is not subject to feedback control, allowing increased uptake of glucose.

Ref: Murray R.K., Jacob M., Varghese J. (2011). Chapter 55. Cancer: An Overview. In D.A. Bender, K.M. Botham, P.A. Weil, P.J. Kennelly, R.K. Murray, V.W. Rodwell (Eds), Harper's Illustrated Biochemistry, 29e.


Which of the following is NOT done by insulin?


C: LipogenesisD: Increases ketogenesisCorrect Ans:DExplanation

Insulin prevents or decreases ketogenesis. It doesnot increase ketogenesis so this is the right choice. Rest all process is done by Insulin.

Also Know:Effect of Insulin on various tissues:

Adipose tissue:

Increased glucose entry Increased fatty acid synthesis Increased glycerol phosphate synthesis Increased triglyceride deposition Activation of lipoprotein lipase Inhibition of hormone-sensitive lipase Increased K+ uptake

Muscle:

Increased glucose entry Increased glycogen synthesis Increased amino acid uptake Increased protein synthesis in ribosomes Decreased protein catabolism Decreased release of gluconeogenic amino acids Increased ketone uptake Increased K+ uptake

Liver: Decreased ketogenesis

Increased protein synthesis Increased lipid synthesis Decreased glucose output due to decreased gluconeogenesis, increased glycogen synthesis, and increased glycolysis

General: Increased cell growth

Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 24. Endocrine Functions of the Pancreas & Regulation of Carbohydrate Metabolism. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.


Estrogen action on carbohydrate metabolism:

A: Increases uptake of glucose through increase in insulin sensitivityB: Increases glycolysisC: Increase central adipose depositionD: Worsening of NIDDM

Correct Ans:AExplanation

Estrogen apparently increases the sensitivity of insulin dependent metabolic processes, (such as tissue glucose uptake and lipid synthesis) to insulin, whereas progesterone has the opposite effect.

Estrogen affects the expression of apoprotein genes and increases lipoprotein receptor expression, resulting in a decrease in serum concentrations of total cholesterol and low-density lipoprotein (LDL) cholesterol, increases in serum high-density lipoprotein cholesterol and triglyceride concentrations, and decreases in serum lipoprotein A concentrations.

Estrogen regulates the hepatic expression of genes involved in coagulation and fibrinolysis.

Estrogen decreases plasma concentrations of fibrinogen, antithrombin III and protein S, and plasminogen activator inhibitor type 1.

Estrogen stimulates the synthesis of transport proteins (thyroxine-binding globulin and transcortin).

Ref: Molina P.E. (2010). Chapter 9. Female Reproductive System. In P.E. Molina (Ed), Endocrine Physiology, 3e.


All of the following metabolic actions are done by insulin, EXCEPT:

A: Glycogen synthesisB: GlycolysisC: Decreases lipid synthesisD: Decreases ketogenesis

Correct Ans:CExplanation

Insulin does not decrease lipid synthesis. It increases lipid synthesis. Rest all process is done by Insulin.

Also Know:Effect of Insulin on various tissues:Adipose tissue:

Increased glucose entry Increased fatty acid synthesis Increased glycerol phosphate synthesis Increased triglyceride deposition Activation of lipoprotein lipase Inhibition of hormone-sensitive lipase Increased K+ uptake

Muscle:

Increased glucose entry Increased glycogen synthesis Increased amino acid uptake Increased protein synthesis in ribosomes Decreased protein catabolism Decreased release of gluconeogenic amino acids Increased ketone uptake Increased K+ uptake

Liver:

Decreased ketogenesis Increased protein synthesis Increased lipid synthesis Decreased glucose output due to decreased gluconeogenesis, increased

glycogen synthesis, and increased glycolysis

General:

Increased cell growth



Which of the following physiological action is NOT done by insulin?


C: LipogenesisD: KetogenesisCorrect Ans:DExplanationKetogenesis occurs in insulin deficiency.

Principal Actions of Insulin:

Rapid (seconds)

Increased transport of glucose, amino acids, and K+ into insulin-sensitive cells

Intermediate (minutes)

Stimulation of protein synthesis Inhibition of protein degradation Activation of glycolytic enzymes and glycogen synthase Inhibition of phosphorylase and gluconeogenic enzymes

Delayed (hours)

Increase in mRNAs for lipogenic and other enzymes



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Previous year question on glycolysis based on neet pg, usmle, plab and fmge or mci screening exams