Homework Answers
Answer to 14.53
- Step 1: glucose → glucose 6-phosphate (G6P), in a reaction catalyzed by hexokinase. In this step, an ATP is invested; more specifically, a phosphate group from ATP is transferred to glucose to form G6P.
- Step 3: fructose 6-phosphate (F6P) → fructose 1,6-bisphosphate (F1,6BP), which is catalyzed by phosphofructokinase-1. Mechanistically, this is similar to step 1; an ATP is invested, and the phosphate group is transferred to F6P to form F1,6BP. However, this is the committed step of glycolysis and is subject to especially strict regulation.
- Step 10: phosphoenolpyruvate (PEP) → pyruvate, which is catalyzed by pyruvate kinase. This step forms ATP, is subject to regulation, and is the end of glycolysis. It generates pyruvate, which the cell can further feed into the citric acid cycle.
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14.53 Which three steps in glycolysis cannot be directly reversed during gluconeogenesis?
Question #7 (10 points) - Which steps of glycolysis are not reversible for gluconeogenesis? How are...
Question #7 (10 points) - Which steps of glycolysis are not reversible for gluconeogenesis? How are these steps reversed during gluconeogenesis?
1. Bypassing the pyruvate kinase reaction. Gluconeogenesis and glycolysis are opposing pathways that share seven enzymes....
1. Bypassing the pyruvate kinase reaction. Gluconeogenesis and glycolysis are opposing pathways that share seven enzymes. The exergonic steps in glycolysis cannot be simply reversed because that would be too energetically costly. Thus, these steps are "bypassed" in gluconeogenesis with a separate set of enzymes. a. Explain why the reaction catalyzed by pyruvate kinase is energetically favorable and essentially irreversible in the cells. b.Explain how the cells that run gluconeogenesis are able to bypass this step with specific reactions that...
What is not true about gluconeogenesis? Select one: a. Gluconeogenesis shares seven steps of glycolysis b....
What is not true about gluconeogenesis?
Select one:
a. Gluconeogenesis shares seven steps of glycolysis
b. Three irreversible steps that differ between gluconeogenesis
and glycolysis are far from equilibrium.
c. Forming one glucose from pyruvate produces 4 ATP, 2 GTP and
2NADH
d. Acetyl-CoA can be converted into glucose in plants and
microbes, but not mammals.
e. Gluconeogenesis and glycolysis are reciprocally regulated to
prevent wasteful operation of both pathways at the same time.
D and B are wrong answers...
QUESTION 25 Why does gluconeogenesis utilize several unique steps compared to glycolysis? a. it doesn't; gluconeogenesis...
QUESTION 25 Why does gluconeogenesis utilize several unique steps compared to glycolysis? a. it doesn't; gluconeogenesis is a direct reversal of glycolysis b. to overcome large energy barriers at those steps gluconeogenesis does not involve NAD/NADH, unlike glycolysis d. the unique steps in gluconeogenesis do not require any enzymes
Which of the steps in glycolysis form substrate cycles in conjunction with gluconeogenesis? (substrate cycles are...
Which of the steps in glycolysis form substrate cycles in conjunction with gluconeogenesis? (substrate cycles are the same thing as futile cycles) O 2 0
Need some help with this question Gluconeogenesis is not quite the exact reverse process of glycolysis,...
Need some help with this question Gluconeogenesis is not quite the exact reverse process of glycolysis, as three key biosynthetic steps used in glycolysis must be bypassed when performing gluconeogenesis. Why are the bypasses of the first and third steps of glycolysis,used in gluconeogenesis, easier to achieve than bypass of the last step?
A) List, in order, the three enzymes that catalyze the highly regulated steps in glycolysis. (Don't...
A) List, in order, the three enzymes that catalyze the highly regulated steps in glycolysis. (Don't just enter 1, 2, 3 for reaction numbers - give the reaction number based on the 10 steps of glycolysis.) Reaction # Enzyme Reaction # Enzyme Reaction # Enzyme B) For each of these reactions, name ONE allosteric regulator of the enzyme and whether that regulator inhibits or activates the enzyme. Reaction # allosteric regulator Inhibitor or activator? Reaction # allosteric regulator Inhibitor or...
Glycolysis and gluconeogenesis are concurrent and complementary metabolic pathways. Which of the following IS NOT TRUE...
Glycolysis and gluconeogenesis are concurrent and complementary metabolic pathways. Which of the following IS NOT TRUE a) glycolysis and gluconeogenesis regulate the availability of glucose in the cell b) all enzymes and intermediates used in glycolysis and gluconeogenesis are the same, glucose, respectively anabolizes acetyl-CoA and pyruvate to glucose. fructose 16P into fructose 6P (final step) in gluconeogenesis uses pathway specific ) glycolysis catabolizes glucose to pyruvate and acetyl-CoA and gluconeogenesis d) the conversion of pyruvate into phosphoenolpyruvate (first step)...
In which of the following metabolic conversions is ATP "consumed" during glycolysis? During glycolysis, the steps...
In which of the following metabolic conversions is ATP "consumed" during glycolysis? During glycolysis, the steps between glucose and formation of the triose phosphates In skeletal muscle cells, the NADH that is produced by glycolysis under anaerobic conditions (vigorous exercise) is regenerated to NAD^+ by the conversion of:
1-Select the steps of glycolysis that are downregulated by ATP. Group of answer choices Fru 6-PO4...
1-Select the steps of glycolysis that are downregulated by ATP. Group of answer choices Fru 6-PO4 --> Fru-1,6-PO4 GA-3-P --> 1,3-bisphosphoglycerate Phosphoenol pyruvate --> Pyruvaate Glc --> Glc-6-PO4 2- Which best describes the effect of AMP? Downregulates Glycolysis Upregulates Gluconeogenesis Upregulates Glycolysis Upregulates Gluconeogenesis & Downregulates Glycolysis Downregulates Gluconeogenesis Downregulates Gluconeogenesis & Upregulates Glycolysis
Question #7 (10 points) - Which steps of glycolysis are not reversible for gluconeogenesis? How are these steps reversed during gluconeogenesis?
What is not true about gluconeogenesis?
Select one:
a. Gluconeogenesis shares seven steps of glycolysis
b. Three irreversible steps that differ between gluconeogenesis
and glycolysis are far from equilibrium.
c. Forming one glucose from pyruvate produces 4 ATP, 2 GTP and
2NADH
d. Acetyl-CoA can be converted into glucose in plants and
microbes, but not mammals.
e. Gluconeogenesis and glycolysis are reciprocally regulated to
prevent wasteful operation of both pathways at the same time.
D and B are wrong answers...
QUESTION 25 Why does gluconeogenesis utilize several unique steps compared to glycolysis? a. it doesn't; gluconeogenesis is a direct reversal of glycolysis b. to overcome large energy barriers at those steps gluconeogenesis does not involve NAD/NADH, unlike glycolysis d. the unique steps in gluconeogenesis do not require any enzymes
Which of the steps in glycolysis form substrate cycles in conjunction with gluconeogenesis? (substrate cycles are the same thing as futile cycles) O 2 0
A) List, in order, the three enzymes that catalyze the highly regulated steps in glycolysis. (Don't just enter 1, 2, 3 for reaction numbers - give the reaction number based on the 10 steps of glycolysis.) Reaction # Enzyme Reaction # Enzyme Reaction # Enzyme B) For each of these reactions, name ONE allosteric regulator of the enzyme and whether that regulator inhibits or activates the enzyme. Reaction # allosteric regulator Inhibitor or activator? Reaction # allosteric regulator Inhibitor or...
Glycolysis and gluconeogenesis are concurrent and complementary metabolic pathways. Which of the following IS NOT TRUE a) glycolysis and gluconeogenesis regulate the availability of glucose in the cell b) all enzymes and intermediates used in glycolysis and gluconeogenesis are the same, glucose, respectively anabolizes acetyl-CoA and pyruvate to glucose. fructose 16P into fructose 6P (final step) in gluconeogenesis uses pathway specific ) glycolysis catabolizes glucose to pyruvate and acetyl-CoA and gluconeogenesis d) the conversion of pyruvate into phosphoenolpyruvate (first step)...
In which of the following metabolic conversions is ATP "consumed" during glycolysis? During glycolysis, the steps between glucose and formation of the triose phosphates In skeletal muscle cells, the NADH that is produced by glycolysis under anaerobic conditions (vigorous exercise) is regenerated to NAD^+ by the conversion of:
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