BioChem Class #20

NADPH is required for glycolysis Select one: True False

False

AMP and fructose 2,6-bisphosphate will: Select one: a. Allosterically inhibit fructose1,6-bisphosphatase and activate PFK-1 b. Allosterically activate pyruvate carboxylase and inhibit pyruvate dehydrogenase c. Inhibit pyruvate kinase and activate hexokinase d. Allosterically inhibit PEP carboxykinase (PEPCK) and activate pyruvate kinase

a

Glycolysis is Select one: a. An anabolic pathway converting glucose to pyruvate that results in net ATP production b. A catabolic pathway converting glucose to pyruvate that results in net ATP production c. An anabolic pathway converting glucose to pyruvate that results in net ATP consumption d.A catabolic pathway converting glucose to pyruvate that results in net ATP consumption Clear my choice

a

Glycolysis produces Select one: a. A net of two ATP molecules per glucose as well as some NADH b.A net of zero ATP molecules and 2 NADPH molecules per glucose c. A net consumption of 2 ATP molecules per glucose and 2 molecules of NADPH d. A net of two ATP molecules per glucose and some CO2 Clear my choice

a

Phosphofructokinase (PFK) catalyzes the conversion of Fructose-6-phosphate to Fructose-1,6-bisphosphate. Identify the concentrations of ATP and ADP that will result in maximal activity of PFK. Select one: a.Low ATP, High ADP b.High ATP, Low ADP c.Low ATP, Low ADP d.High ATP, High, ADP

a

Which of the following is correct regarding the regulation of glycolysis? Select one: a. hexokinase undergoes feedback inhibition by glucose-6-phosphate; pyruvate kinase undergoes feed-forward activation by fructose-1,6-bisphosphate b. ATP inhibits all glycolytic enzymes; AMP activates all glycolytic enzymes c. PFK undergoes feedforward activation by fructose-2,6-bisphosphate; PFK undergoes feed-back inhibition by citrate d. hexokinase undergoes feedback inhibition by AMP; pyruvate kinase undergoes feed-forward activation by fructose-2,6-bisphosphate Clear my choice

a

Which option below accurately reflects net yields for glycolysis in humans, starting with 1 molecule of glucose? Select one: a.2 ATP, 2 NADH, 2 pyruvate b.4 ATP, 4 NADH, 2 pyruvate c.2 ATP, 4 NADH, 2 CO2 d.4 ATP, 2 NADH, 2 pyruvate

a

Which option below best describes the inputs (substrates and reactants) for glycolysis? (the stoichiometric amounts are not given) Select one: a. glucose, NAD+, Pi b. glucose, NADH, O2 c. glucose, NAD+, Pi, CO2 d. glucose, NAD+, O2, Pi

a

Which statement below best describes what glycolysis accomplishes? Select one: a. Oxidation of glucose to pyruvate with generation of some ATP and NADH; it does not require O2 and does not produce CO2 b. Breakdown of glucose to pyruvate with net generation of 2 ATP; it requires O2 and occurs in the cytosol c. Oxidation of glucose to lactate with the generation of ATP in the mitchondria d.Oxidation of glucose to CO2 with generation of ATP and NADH in the presence oxygen in the mitochondria

a

Which of the follow correctly describes the reaction catalyzed by glyceraldehyde-3-phosphate dehydrogenase? (select all that apply) Select one or more: a. inorganic phosphate (Pi) is incorporated into the substrate b. the dehydrogenase produces a 'high-energy' compound c. the dehydrogenase performs substrate-level phosphorylation d. NADH is produced e. The dehydrogenase is an oxidoreductase

a, b, d, e

PFK is the major regulatory step in glycolysis. Which of the following compounds serve to ACTIVATE PFK? (select all that apply) Select one or more: a.Fructose-2,6-bisphosphate b. Citrate c. Glucose-6-phosphate d. ADP e. Fructose-6-phosphate f. AMP g. Pi h. Pyruvate i. NAD+ j. ATP k. Glucose l. NADH m. PEP

a, d, f

In glycolysis Select one: a. there is just one reaction that is far from equilibrium and it is reversible b. there are several reactions that are far from equilibrium and irreversible c. no reactions are near equilibrium, all steps are far from equilibrium and irreversible d. there are no reactions that are far from equilibrium, with all steps being easily reversible.

b

In glycolysis, phosphofructokinase-1: Select one: a.will produce fructose 1,6-bisphosphate; while it is activated by AMP to produce fructose 1-phosphate in gluconeogenesis because it is bifunctional b.is the rate limiting step as well as the most regulated; it is allosterically inhibited by ATP and citrate c.it is allosterically activated by NADH and represents the critical control point of glycolysis d.catalyzes a near-equilibrium reaction using a high phosphoryl transfer potential substrate to make ATP

b

Study the reactions of glycolysis. Which statement is correct concerning reactions that are near-equilibrium vs. far-from-equilibrium as found in glycolysis? Select one: a. All glycolytic reactions are far from equilibrium because the pathway of glycolysis has a large and negative change in Gibbs Free Energy. b. PGM and PGI catalyze near equilibrium reactions while hexokinase is a far from equilibrium reaction c. All glycolytic reactions are near equilibrium reactions because gluconeogenesis is the reverse of glycolysis d. PK and PFK are catalyze near equilibrium reactions while hexokinase is a far from equilibrium reaction e. Hexokinase is a near-equilibrium reaction while TIM is a far from equilibrium reaction Clear my choice

b

What is significant regarding the step converting fructose 6-phosphate to fructose 1,6-bisphophate in glycolysis: Select one: a.It utilizes inorganic phosphate and releases CO2 b.It is the rate-limiting step that is far from equilibrium and highly regulated c.It generates the first high-energy intermediate and produces ATP by substrate level phosphorylation d.It is an oxidation-reduction reaction that regenerates needed NAD+

b

Which of the following are properly described allosteric regulators of PFK in glycolysis? Select one: a. ATP is an activator and NAD+ is an activator b. citrate is an inhibitor and fructose-2,6-bP is an activator c. AMP is an inhibitor and ATP is an inhibitor d. Fructose-2,6-bP is an inhibitor and Fructose-1,6-bP is an activator

b

Which of the following correctly describes the reaction catalyzed by GAP dehydrogenase in glycolysis, which is a very critical reaction? Select one: a. it consumes ATP, produces a high energy product, and oxidizes NADH b. it generates a high energy product, produces NADH, and requires Pi as a substrate c. it is a near equilibrium isomerase that generates the NADH needed for fermentation d. it reduces NAD+, generates ATP by substrate-level phosphorylation, and is near equilibrium

b

Which of the following statements is correct regarding enzymes in glycolysis? Select one: a. Every enzyme in the pathway produces a high energy compound as a product b. Some enzymes operate far-from equilibrium and these enzymes are regulated c. All enzymes are near-equilibrium and readily reversible

b

Which of the following statements is correct regarding the regulation of glycolysis? Select one: a. Hexokinase is the first step (in muscle) and, as such, is the major regulatory step. It is inhibited by glucose-6-phosphate and fructose-2,6-bisphosphate b. PFK is the major regulatory step and it is activated by AMP and Fructose-2,6-bisphosphate, while ATP inhibits it c. PFK is the major regulatory step and it is activated by ADP and Fructose-1,6-bisphosphate, while citrate and ATP inhibit it d. Pyruvate kinase is the major regulatory step and it is inhibited by AMP and citrate

b

Which statement below best summarizes glycolysis with respect to reactions near and far from equilibrium and regulation? Select one: a. 3 reactions are near equilibrium and highly regulated; the remaining 7 reactions are far from equilibrium and not regulated b. 3 reactions are far from equilibrium and highly regulated; the remaining 7 reactions are near-equilibrium and not regulated c. all reactions in glycolysis are near-equilibrium and 3 reactions are highly regulated d. all reactions in glycolysis are from from equilibrium and 3 reactions are highly regulated

b

Which step in glycolysis is the major regulatory step? Select one: a. GAP dehydrogenase b. PFK c. pyruvate kinase d. hexokinase Clear my choice

b

Which steps in glycolysis are far-from equilibrium? (select all that apply) Select one or more: a. phosphoglycerate mutase (step #8) b. Hexokinase (step #1) c. pyruvate kinase (step #10) d. PFK (step #3) e. phosphoglycerate kinase (step #7) f. Phosphoglucoisomerase (step #1) g. TIM (triose phosphate isomerase) (step #5) h. Aldolase (step #4) i. Glyceraldehyde-3-phosphate dehydrogenase (step #6) j. enolase (step #9)

b, c, d

Which of the following are NET products of glycolysis from 1 molecule of glucose? (glycolysis is defined as glucose --> --> --> pyruvate) check all that apply Select one or more: a. Pi b. ATP c. Acetyl-CoA d. NADH e. ADP f. pyruvate g. O2 h. CO2

b, d, f

Which enzymatic steps in glycolysis are irreversible and/or the main targets of glycolytic regulation? (select all that apply; incorrect selections are penalized) Select one or more: a. glyceraldehyde-3-phosphate dehydrogenase b. pyruvate kinase c. enolase d. aldolase e. hexokinase f. PFK

b, e, f

ATP is a product of the last step of the glycolysis pathway. Phosphofructokinase (PFK) is an enzyme near the beginning of the glycolysis pathway. It is a kinase that converts fructose-6-phosphate and ATP to fructose-1,6 bisphosphate and ADP. The fact that the velocity of PFK decreases with increasing ATP concentration suggests which of the following: Select one: a. PFK is inhibited by glucose and activated by cAMP b. PFK is an allosteric enzyme that is inhibited by ATP; it is a monomer c. PFK is an allosteric enzyme that is inhibited by ATP; it has quaternary structure d. PFK is an allosteric enzyme that is activated by ADP; it has quaternary structure

c

Glycolysis requires Select one: a. Consumption of 2 NADH molecules and incorporation of 2 Pi molecules b. An investment of 2 ADP per glucose c. An investment of 2 ATP molecules, as well as incorporation of 2 Pi molecules, and usage of 2 NAD+ per glucose d. An investment of 1 ATP molecule and 1 ADP, and usage of 1 NADP+ per glucose

c

The glycolytic pathway oxidizes glucose to two molecules of pyruvate and also produces a net of two molecules of ATP. ATP allosterically inhibits the enzyme, PFK-1, that catalyzes the third step of glycolysis. This is an example of ________. Select one: a.negative cooperativity b.competitive inhibition c.feedback inhibition d.feed-forward activation Clear my choice

c

The pathway of glycolysis: Select one: a. Is overall an energy consuming reactions with all reactions being irreversible and far-from equilibrium b. Is at equilibrium with no steps being irreversible and all steps being regulated for flux c. Has an overall net negative Gibbs Free Energy with 3 irreversible reactions that are far-from equilibrium and the remaining reactions being near-equilibrium d. Has an overall net negative Gibbs Free Energy due to each reaction being both irreversible and near-equilibrium

c

Which glycolytic enzyme below typically catalyzes a near-equilibrium step in the cell under usual (steady-state) conditions? a. hexokinase b. pyruvate kinase c. GAP Dehydrogenase d. PFK

c

Which of the following correctly describes the Gibbs Free Energy change for the entire glycolytic pathway? a. The standard Gibbs Free Energy change is negative; if glycolysis is active, then the actual change in Gibbs Free Energy is positive b. The standard Gibbs Free Energy change is positive; if glycolysis is active, then the actual change in Gibbs Free Energy is negative, too. c. The standard Gibbs Free Energy change is negative; if glycolysis is active, then the actual change in Gibbs Free Energy is negative, too.

c

Which statement below best describes the term "substrate-level phosphorylation"? a. an unusual, difficult, and dangerous dance move that can only be attempted by the most spry and unassuming dance phenome physicists... like Dr. Rodriguez b. a kinase uses and ATP to transfer a phosphate from ATP onto a second substrate molecule c. making ATP in an enzymatic reaction from a high energy substrate molecule d. making ATP through the proton gradient generated at the electron transport chain

c

Which of the following are high energy molecules generated in glycolysis? Select all that apply Select one or more: a. pyruvate b. glucose-6-phosphate c. PEP d. NADH e. GAP f. 2BP g. 1,3-bPG

c and g

The first enzyme in the glycolysis pathway is hexokinase; while pyruvate kinase (PK) is the last. Based on the data handed out, which statement below best describes the actual change in Gibbs Free Energy for the glycolysis pathway in heart muscle cells? Select one: a. The pathway is exergonic with a change of about -25kJ/mol b.Glycolysis does not generate net energy, so the change in Gibbs Free Energy is 0.0kJ/mole c. The pathway is endergonic with a change of about +25kJ/mol d. The pathway is exergonic with a change of about -80kJ/mol e. The pathway is exergonic with a change of about -55kJ/mol f. The pathway is endergonic with a change of about +55 kJ/mol g. The pathway is endergonic with a change of about +80kJ/mol

d

Study the reactions of glycolysis. Which equation best summarizes the glycolysis pathway: Select one: a. Glucose + 2ADP + 2H2O à 2 pyruvate + 2ATP + CO2 + 2H+ b. Glucose + Pi + NAD+ à pyruvate + NADH + H2O + H+ c. Glucose + 2ATP + NAD+ à pyruvate + 2ADP + NADH + 2H2O + 2Pi + H+ d. Glucose + 2Pi + 2NADH + H+ à 2 pyruvate + 2NAD+ e. Glucose + 2ADP + 2Pi + 2NAD+ à 2 pyruvate + 2ATP + 2NADH + 2H2O + H+

e

Reactions in glycolysis are also part of the electron transport chain (ETC) Select one: True False

false

Glycolysis does not require oxygen Select one: True False

true