(a)
Interpretation:
The effects of increasing the concentration of tissue fructose-1,6-bisphosphate on the rates of gluconeogenesis and glycogen
Concept Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two-enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(b)
Interpretation:
The effects of increasing the concentration of blood glucose on the rates of gluconeogenesis and glycogen metabolism should be explained.
Concept Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(c)
To Explain:
The effects of increasing the concentration of blood insulin on the rates of gluconeogenesis and glycogen metabolism should be explained.
Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(d)
To Explain:
The effects of increasing the amount of blood glucagon on the rates of gluconeogenesis and glycogen metabolism should be explained.
Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(e)
Interpretation:
The effects of decreasing levels of tissue ATP on the rates of gluconeogenesis and glycogen metabolism should be explained.
Concept Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(f)
Interpretation:
The effects of increasing the concentration of tissue AMP on the rates of gluconeogenesis and glycogen metabolism should be explained.
Concept Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
(g)
Interpretation:
The effects of decreasing the concentration of fructose-6-phosphate on the rates of gluconeogenesis and glycogen metabolism should be explained.
Concept Introduction:
Most of the reactions in Glycolysis and Gluconeogenesis reactions are taken place in the cytosol. Therefore, unless there is a metabolic regulation, glycolytic degradation of glucose and gluconeogenic synthesis of glucose will occur simultaneously without a benefit to the cell with huge consumption of ATP. This scenario is controlled by a reciprocal control system which inhibits glycolysis when gluconeogenesis is active and vice versa.
Glucose produced by glycogen metabolism is also an energy source for muscle contraction. Regulation of glycogen metabolism is also a reciprocal control of the two enzyme glycogen phosphorylase and glycogen synthase. Regulation is achieved via both allosteric regulation and covalent modification.
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Chapter 22 Solutions
Biochemistry
- Glucagon is released from the pancreas in response to low blood glucose levels. It regulates the opposing pathways of glycolysis and gluconeogenesis by altering levels of fructose 2,6-bisphosphate. If glucagon causes a decrease in fructose 2,6-bisphosphate, how does this increase blood glucose levels? Explain..arrow_forwardGlycogen synthesis and breakdown are regulated primarily at the hormonal level. However, important nonhormonal mechanisms also control the rates of synthesis and mobilization. Describe these nonhormonal regulatory processes.arrow_forwardOne of the earliest responses to cellular injury is a rapid increase in the levels of enzymes in the pentose phosphate pathway. About ten days after an injury, levels of glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in heart tissue are 20 to 30 times higher than normal. However the levels of glycolytic enzymes are only 10% to 20% of normal. Explain this phenomenon.arrow_forward
- 1. Draw a detailed labelled diagram and discuss the hormonal (epinephrine orglucagon) regulation of glycogen phosphorylase. 2. Provide your own diagrammatic representation for the entry of any TWOcarbohydrates: mannose or lactose or sucrose or glycerol into the glycolyticpathwayarrow_forwardExplain, the roles of Insulin and glucagon hormones in maintaining blood glucose level. Glycolysis is a pathway which breaks down glucose into two three-carbon compounds. However, Gluconeogenesis is defined as the de novo synthesis of glucose. Can it be said that these two pathways include same reactions but only having inverse direction? Explain by the reasons.arrow_forwardConsider regulation of glycolysis vs gluconeogenesis in the liver. Which of the following are more likely to promote the activity of gluconeogenesis rather than glycolysis? (select all that apply) Group of answer choices An increase in the ATP/AMP ratio A decrease/lack of F-2,6-BP The cell is in a low energy state Insulin signaling Glucagon signaling An abundance of citric acid cycle intermediates (i.e. citrate) Intense exercise Inhibition of pyruvate carboxylase Fastingarrow_forward
- 1.a. Given what you know about glycolysis and gluconeogenesis, does it make sense that insulin activates PDH phosphatase? Why? b.How do vitamins increase to the breadth of chemical reactions available within a biological system?arrow_forwardRegulation of the utilization of important nutritional and energy sources is effected by the following strategies in metabolism EXCEPT During the absorptive stage, when nutrients are plentiful, storage pathways such as lipogenesis and glycogenesis are very active B. During the post absorptive stage, the liver does not use dietary glucose Increased acetyl CoA due to the breakdown of fats will activate the gluconeogenic and ketogenic pathways. Ketone bodies and glucose provides the only sources of energy for the brain Activation and deactivation of enzymes are mediated in most cases by increasing or decreasing the concentration of allosteric effectors.arrow_forwardDeficiencies of carnitine, carnitine acyltransferases, or carnitine/acylcarnitine translocase affect the metabolism of long-chain fatty acids. Many of the symptoms are similar, and include hypoketotic hypoglycemia, low ketone levels and low blood sugar with fasting, and damage to the liver, heart, or muscles due to fatty acid buildup in those tissues. Symptom severity varies with the form of the deficiency. The following abbreviations are used: carnitine acyltransferase (carnitine palmitoyltransferase), CPT and carnitine/acylcarnitine translocase, CACT. Identify each symptom or effect as a deficiency of CPT I, CPT II, or CACT. CPT I deficiency CPT II deficiency CACT deficiency Answer Bank acyl carnitine not transported into mitochondrial matrix long-chain fatty acids not transferred to carnitine long-chain fatty acids remain attached to carnitine in matrixarrow_forward
- c) Cooperation between glycolysis and gluconeogenesis is important to ensure the glucose-subjected energy demands of specific cells are met. Explain this statement.arrow_forwardWith explain fastarrow_forwardIn the fasted state, FADH2 and NADH for oxidative phosphorylation are mainly provided by fatty acid oxidation. Explain how fatty acids are mobilised from adipose tissue by the action of glucagon.arrow_forward
- BiochemistryBiochemistryISBN:9781305577206Author:Reginald H. Garrett, Charles M. GrishamPublisher:Cengage Learning