You identified a mutant yeast whose glycolytic pathway is shorter due to the presence of a new enzyme catalysing the following reaction: Glyceraldehyde-3-Phosphate + H2O + NAD+ → 3-phosphoglycerate + NADH + H+ What would the effect of this mutation have on this mutant yeast’s ability to grow under i) anaerobic conditions?

You identified a mutant yeast whose glycolytic pathway is shorter due to the presence of a new enzyme catalysing the following reaction: Glyceraldehyde-3-Phosphate + H2O + NAD+ → 3-phosphoglycerate + NADH + H+ What would the effect of this mutation have on this mutant yeast’s ability to grow under i) anaerobic conditions?

Biochemistry

6th Edition

ISBN:9781305577206

Author:Reginald H. Garrett, Charles M. Grisham

Publisher:Reginald H. Garrett, Charles M. Grisham

Chapter27: Metabolic Integration And Organ Specialization

Section: Chapter Questions

Problem 20P: Figure 27.3 illustrates the response of R (ATP-regenerating) and U (ATP-utilizing) enzymes to energy...

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the reaction catalyzed by glyceradehyde 3-phosphate dehydrigenase is based on NAD+ and a active site cysteine. Also another phosphate group is added. what is the reason for that? a) because one ATP is consumed b) an inorganic phosphate is activated for ATP synthesis C) NADH can be recycld and than converted back to NAD+ for glycolysis d) because one ATP is generated
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
Why are there reversible steps in the glycolytic pathway? Explain why they all be could not be irreversible?
A “pulse-chase” experiment using 14C-labeled carbon sources is carried out on a yeast extract maintained under strictly anaerobic conditions to produce ethanol. The experiment consists of incubating a small amount of14C-labeled substrate (the pulse) with the yeast extract just long enough for each intermediate in the fermentation pathway to become labeled. The label is then “chased” through the pathway by the addition of excess unlabeled glucose. The chase effectively prevents any further entry of labeled glucose into the pathway.(a) If [1-14C]glucose (glucose labeled at C-1 with 14C) is used as a substrate, what is the location of 14C in the product ethanol? Explain.(b) Where would 14C have to be located in the starting glucose to ensure that all the 14C activity is liberated as 14CO2 during fermentation to ethanol? Explain.
What is the fate of the radioactive label when each of the following pairs of compounds is added to a cell extract containing the enzymes and cofactors of the glycolytic pathway, the citric acid cycle, and the pyruvate dehydrogenase complex? The 14C label is noted with an *. || + unlabelled oxaloacetate a) H3C- * pyruvate b) unlabelled pyruvate + H2 охaloacetate Guidelines Show enough structures along the way so your logic can be followed. You do not need to show every structure along the way. • Go around the citric acid cycle until all of the label has come off as CO2 (or until you can see a pattern develop - you can then just state the pattern in words). If you need to go around the citric acid cycle more than once (it won't for this problem!), assume that the acetyl CoA that enters on all subsequent turns is not labeled.
You have genetically engineered a yeast protein to convert Glyceraldehyde-3-phosphate directly to 3-phosphoglycerate. Give a detailed explanation of how this protein would affect the growth of yeast cells and energy production as well as under what conditions (aerobic/anaerobic) these would be affected.
Fructose-6-phosphate is an important intermediate in glycolysis but it does not necessarily have to enter the pathway as a product of the phosphoglucoisomerase reaction. What are 2 ways used by organisms to make fructose-6-phosphate WITHOUT the phosphoglucoisomerase enzyme? Select one: O a. Phosphorolysis of glycogen to release fructose-6-phosphate. Dephosphorylation of uridine diphosphate by UDP-glucose pyrophosphorylase. O b. Isomerization of glucose-6-phosphate by phosphoglucomutase. Dephosphorylation of fructose bisphosphate by phosphoglycerate kinase. O c. Reversing the phosphofructose kinase reaction. Isomerizing phosphoenol pyruvate with fructose bisphosphate aldolase. O d. Direct phosphorylation of fructose by hexokinase. Phosphorylation of mannose by hexokinase followed by isomerization of mannose-6-phosphate by phosphomannose isomerase
Some anaerobic bacteria use alternative pathways for glucose catabolism that convert glucose to acetate rather than to pyruvate. Shown below is one possible metabolic pathway. The first part of this pathway (glucose to fructose-1,6-bisphosphate) is identical to the glycolytic pathway. In the second part of the alternative pathway, Enzymes 1–6 all have mechanisms/ activities analogous t enzymes in glycolysis. Note that there are two C¬C bond cleavage reactions in this new pathway: A → B + C (Enzyme 1) and C → B + D. All the steps where ATP is consumed or generated have been shown; however, the addition or loss of NAD+/NADH, Pi , H2O, or H+ has not been shown explicitly. Draw the structures for the intermediates B, F, G, H, and I, and include other reaction participants as needed.
Consider the malate dehydrogenase reaction, part of tricarboxylic acid cycle,shown below.malate + NAD+ <==> oxaloacetate + NADH + H+ ΔGo’ = 29.7 kJ/molIt has been reported (Wheeler and Mathews (2012) J. Biol. Chem. 887, 31218-31222) that theconcentrations of NAD+ and NADH in yeast mitochondria were 20 mM and 0.3 mM,respectively. If we performed similar measurements and also determined that the concentrationof malate in yeast mitochondria was 0.5 mM and that of oxaloacetate was 0.1 µM at pH 7.0 at37˚C, use this information to address the following.Calculate the equilibrium constant for the given reaction. Calculate the free energy of the reaction in yeast mitochondria. Assign each reaction (the one under standard conditions and the one in yeastmitochondria) as being exergonic or endergonic. Explain your reasoning. When comparing the free energy values for standard conditions and the conditionsin yeast mitochondria describe the relationship between the equilibrium constant (K)…
In several species of bacteria, GAPDH activity is controlled by the NADH/NAD+ ratio. Does the activity of GAPDH increase or decrease when the NADH/NAD+ ratio increases? Explain. Assume that only the forward direction of the reaction is relevant. a) The activity of GAPDH increases when the NADH/NAD+ ratio increases. b) The activity of GAPDH decreases when the NADH/NAD+ ratio increases.
Consider 3 molecules of galactose: (write only the whole number; no decimal places) How many turns of Krebs Cycle will these molecules undergo for complete oxidation? b. How many moles of ATP are produced upon complete oxidation via malate-aspartate shuttle? c. If all the galactose molecules oxidize via pentose phosphate pathway (oxidative stage only), how many moles of NADPH will be produced?
Match each of the enzymes involved in de novo pyrimidine synthesis with the correct description: _______ Dihydroorotate dehydrogenase _______ UMP synthase_______ Carbamoyl phosphate synthetase II _______ TMP synthase _______ CTP synthetase_______ Aspartate transcarbamoylase _______ PRPP synthetase (A) attaches an aspartate to an activated carbamoyl molecule(B) bifunctional enzyme that combines a nitrogenase pyrimidine ring to an activated ribose(C) catalyzes the formation of the activated ribose sugar(D) uses glutamine to add an amine to a preformed nucleotide(E) produces the first cyclic nitrogenase ring during de novo pyrimidine synthesis(F) combines bicarbonate and nitrogen from glutamine in the first step of pyrimidine ring synthesis (G) uses a folate derivative to add a methyl group to a preformed nucleotide