Studied by 0 people
Looks like no one added any tags here yet for you.
Which metabolic pathway is only found in plants?
carbon fixation
Which of the following is least likely to affect the metabolic flux of a metabolic pathway?
Steady-state substrate concentrations
Which of the following is NOT an outcome of glycolysis?
Generation of 1 pyruvate
Based on the free energy change, which of the following steps in glycolysis would be considered irreversible under cellular conditions?
Step 3
Glucokinase is important for the regulation of glycolysis because it
traps extra glucose in liver cells for glycogen production
Which of the following fates of pyruvate is correct?
Pyruvate enters the citrate cycle under aerobic conditions
Pyruvate is fermented to ethanol under aerobic conditions
Pyruvate enters the citrate cycle under anaerobic conditions
Pyruvate is converted to lactate under aerobic conditions
Pyruvate enters the citrate cycle under aerobic conditions
Under anaerobic conditions, pyruvate is metabolized to either ethanol or lactate to provide which important coenzyme?
NAD+
Reactions that occur in glycolysis can all be described in terms of the chemical changes that occur within each. Place the descriptions of these chemical reactions in the order that they occur in stage I of glycolysis (from beginning to end).
Beginning
Phosphoryl transfer from ATP to aldose
Isomerization of aldose to ketose
Phosphoryl transfer from ATP to ketose
Reverse of aldol condensation
Isomerization of ketose to aldose
End
Which enzymes in glycolysis catalyze the isomerization of an aldose to a ketose or vice versa?
phosphoglucoisomerase
triose phosphate isomerase
What is the net reaction for stage I of glycolysis if the pathway begins with 2 moles of glucose?
2 Glucose + 4 ATP → 4 Glyceraldehyde-3-phosphate + 4 ADP
If 2 moles of glucose were converted into 4 moles of pyruvate through the glycolytic pathway, there would be a net yield of
4 ATP
A net yield of ______ ATP would be produced from the conversion of three molecules of glucose into pyruvate
6
The flux of which of the following reactions would depend only on substrate availability?
dihydroxyacetonephosphate → glyceraldehyde-3-phosphate
glucose-6-phosphate → fructose-6-phosphate
Glycolytic reactions can either be described as reversible or irreversible. Looking at all 10 reactions in glycolysis, what conclusions can you make about irreversible reactions in general?
The activity of the enzymes that catalyze irreversible reactions can be increased or decreased
They operate far from equilibrium
The enzymes that catalyze these reactions are not shared in opposing
pathways (i.e., glycolysis and gluconeogenesis)
Kinases most commonly use which substrate as a source of phosphate for phosphoryl transfer reactions?
ATP-Mg2+
Which statement explains why glucose phosphorylation could not occur without ATP investment?
Without ATP investment, one or both of the substrates would need to exceed the solvent capacity of the cell for glucose phosphorylation to occur.
(A) Phosphorylation of glucose to produce glucose-6-phosphate has ΔG˚' = ______ kJ/mol without the use of ATP.
(B) Coupling phosphorylation with ATP hydrolysis gives ΔG˚' = _______ kJ/mol
13.8 kJ/mol
-16.7 kJ/mol
Using concentrations of intermediates found in a cell, the phosphorylation of glucose using inorganic phosphate has ΔG' = 19.7 kJ/mol, while phosphoryl transfer from ATP (ATP investment) results in ΔG' = -34.5 kJ/mol. What does this tell you about the values of Q and Keq for the phosphorylation of glucose with and without energy investment from ATP?
Without ATP investment, Q > Keq, and with ATP investment Q < Keq
How many enzymes catalyze irreversible reactions in stage I of glycolysis under cellular conditions?
2
The last reaction in glycolysis involves transfer of a phosphate group from phosphoenolpyruvate to ADP, yielding pyruvate and ATP. The coupled ΔG°' of this reaction is -31.4 kJ/mol. If ΔG°' of ATP hydrolysis is -30.5 kJ/mol, what is the ΔG°' of hydrolysis of phosphoenolpyruvate?
-61.9 kJ/mol
