Although both hexokinase and phosphofructokinase catalyze irreversible steps in glycolysis and the hexokinase-catalyzed step isfirst, phosphofructokinase is nonetheless the pacemaker of glycolysis.What does this information tell you about the fate of the glucose 6-phosphate formed by hexokinase?Glucose 6-phosphate must be unstable and release its phosphoryl group over time.Glucose 6-phosphate must be utilized by other metabolic pathways.Glucose 6-phosphate must allosterically inhibit phosphofructokinase, but not hexokinase.Glucose 6-phosphate must be wasted when it is produced in excess.

The metabolic process known as glycolysis, which takes place in the cytosol, the liquid portion of…

Answered: Although both hexokinase and…

Biochemistry

9th Edition

ISBN:9781319114671

Author:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Chapter1: Biochemistry: An Evolving Science

Section: Chapter Questions

Problem 1P

See similar textbooks

Similar questions

Although both hexokinase and phosphofructokinase catalyze irreversible steps in glycolysis and the hexokinase-catalyzed step is first, phosphofructokinase is nonetheless the pacemaker of glycolysis. What does this information tell you about the fate of the glucose 6- phosphate formed by hexokinase?
The glucose/glucose-6-phosphate substrate cycle involves distinct reactions of glycolysis and gluconcogenesis that interconvert these two metabolites. Assume that under physiological conditions, [ATP] = [ADP] and [Pi] =1 mM. Consider the following glycolytic reaction catalyzed by hexokinase: ATP + glucose = AG' = -16.7 kJ/mol ADP + glucose-6-phosphate (a) Calculate the equilibrium constant (K) for this reaction at 298 K, and from that, calculate the maximum [glucose-6-phosphate]/[glucose] ratio that would exist under conditions where the reaction is still thermody- namically favorable. (b) The reverse of this interconversion in gluconeogenesis is catalyzed by glucose-6-phosphatase: glucose-6-phosphate + H,0 = glucose + P, AGr = -13.8 kJ/mol K= 262 for this reaction. Calculate the maximum ratio of [glucose]/ [glucose-6-phosphate] that would exist under conditions where the reaction is still thermodynamically favorable. (c) Under what cellular conditions would both directions in the…
During periods of intense physical exercise, the demand for ATP in muscle tissue increases dramatically. L-lactic acid fermentation accounts for almost all of the ATP production in rabbit leg muscle and turkey flight muscle, respectively. A pair of processes, phosphoglycerate kinase and pyruvate kinase, are involved in the formation of ATP during the payout phase of glycolysis. Assume that the enzyme lactate dehydrogenase is absent from skeletal muscle. Could it withstand rigorous physical activity, that is, could it create large amounts of ATP at a rapid pace via the process of glycolysis? Explain.
The glucose/glucose-6-phosphate substrate cycle involves distinct reactions of glycolysis and gluconeogenesis that interconvert these two metabolites. Assume that under physiological conditions, [ATP] = [ADP]; [P;] = 1 mM. Consider the glycolytic reaction catalyzed by hexokinase: ATP + glucose ADP + glucose-6-phosphate AG = - 16.7 kJ/mol (a) Calculate the equilibrium constant (K) for this reaction at 298°K, and from that, calculate the maximum [glucose-6-phosphate]/ Iglucose] ratio that would exist under conditions where the reaction is still thermodynamically favorable. (b) Reversal of this interconversion in gluconeogenesis is catalyzed by glucose-6-phosphatase: glucose-6-phosphate + H20 = glucose + P AG" = -13.8 kJ/mol
In glycolysis, the conversion of phosphoenolpyruvate (PEP) to pyruvate is considered irreversible. Yet, in gluconeogenesis, this "irreverisble" reaction is bypassed and pyruvate is eventually converted to PEP. Explain how gluconeogenesis bypasses this irreverisble reaction. Include the enzymes required to convert pyruvate to PEP + the intermediate that is created. Imagine a scenario where the PDH complex has picked up an "activating" mutation causing it to convert pyruvate into acetyl CoA in an unregulated manner.There is way too much acetyl CoA than is actually necessary. Explain in a sentence or two how the body would compensate for this
What effect do low-energy phosphagens have on glycolytic rate? (1 point) Which phosphagens (name them all: not just the low-energy ones) are known to affect glycolytic enzymes? How do they regulate glycolysis (I don’t mean increase or decrease)? (What type of regulation is employed?)
Von Gierke’s disease is also known as glycogen storage disease type I. Patients with von Gierke’s disease lackglucose 6-phosphatase activity. Two prominent symptoms of this disorder are fasting hypoglycemia and lactic acidosis (elevated lactate levels in the blood), especially during strenuous exercise. Explain why these symptoms occur. What chemical reaction does this enzyme catalyze? Which pathways involve this enzyme? Lacking thisthe enzyme will cause impairment of which pathways?• Pls consider what pathways are affected by Von Gierke’s disease. Include in your explanation involving Cori’s cycle. can you please do not write by your hand? I mean computer if you can. thank you
Von Gierke’s disease is also known as glycogen storage disease type I. Patients with von Gierke’s disease lackglucose 6-phosphatase activity. Two prominent symptoms of this disorder are fasting hypoglycemia and lactic acidosis (elevated lactate levels in the blood), especially during strenuous exercise. Explain why these symptoms occur. What chemical reaction does this enzyme catalyze? Which pathways involve this enzyme? Lacking thisenzyme will cause impairment of which pathways?• Pls consider what pathways are affected by Von Gierke’s disease. Include in your explanation involving the Cori’s cycle.
Consider an alternative glycolysis pathway that starts with the phosphorylation of glucose to give glucose-6-phosphate. This (hypothetical) pathway exists in a (hypothetical) organism that does not express glucose-6-phosphate isomerase. Instead, the next step of this hypothetical pathway is a Glucose-6-Phosphate Aldolase. Draw the product or products that would be obtain by the reaction of Glucose – 6 – Phosphate with Glucose – 6 Phosphate Aldolase. Assume the reaction is completely irreversible. Explain in 1-3 sentences how you obtained your answer
Draw OUT THE arrow pushing reaction mechanism for the following steps of glycolysis: SHOW/IDENTIFY the arrow pushing mechanism in at least 2 steps. CH,OPO CH,OH hexokinase 2+ H H H H H H ОН + ATP OH H ADP + H+ H ОН + НО HO OH H ОН H ОН Glucose-6-phosphate (G6P) Glucose
Citrate (the product of the first step of the TCA cycle) is considered to be a sign of high energy. 1. Which step of glycolysis does citrate regulate (does it activate or inhibit that step?) 2. WHY exactly is citrate considered a sign of high energy?
Phosphoglycerate mutase (PGM) catalyzes the interconversion of 3-phosphoglycerate (3PG) and 2-phosphoglycerate (2PG) in the glycolytic and gluconeogenic pathways. a) To what enzyme class does PGM belong? b) There are two distinct classes of PGM, one which is dependent on 2,3-bisphosphoglycerate (2,3-BPG), dPGM, and one which is not, iPGM. dPGM uses acid base chemistry and a phosphorylated histidine residue to interconvert 3PG and 2PG. The dPGM reaction proceeds with formation of 2,3-BPG as an intermediate. Propose a mechanism for the dPGM-catalyzed conversion of 3PG to 2PG that is consistent with this information. c) What is the purpose of 2,3-BPG (i.e., why does dPGM require it)?

SEE MORE QUESTIONS

Recommended textbooks for you

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781319114671

Author:

Lubert Stryer, Jeremy M. Berg, John L. Tymoczko, Gregory J. Gatto Jr.

Publisher:

W. H. Freeman

Lehninger Principles of Biochemistry

Biochemistry

ISBN:

9781464126116

Author:

David L. Nelson, Michael M. Cox

Publisher:

W. H. Freeman

Fundamentals of Biochemistry: Life at the Molecul…

Biochemistry

ISBN:

9781118918401

Author:

Donald Voet, Judith G. Voet, Charlotte W. Pratt

Publisher:

WILEY

Biochemistry

ISBN:

9781305961135

Author:

Mary K. Campbell, Shawn O. Farrell, Owen M. McDougal

Publisher:

Cengage Learning

Biochemistry

ISBN:

9781305577206

Author:

Reginald H. Garrett, Charles M. Grisham

Publisher:

Cengage Learning

Fundamentals of General, Organic, and Biological …

Biochemistry

ISBN:

9780134015187

Author:

John E. McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson

Publisher:

PEARSON

SEE MORE TEXTBOOKS