FINAL EXAM CHAPTER 16 Glycolysis Flashcards
Why is glucose such a prominent fuel molecule?
- Glucose may have been available for primitive biochemical systems because it can form under prebiotic conditions.
- Glucose is the most stable hexose
- Glucose has a low tendency to nonenzymatically glycosylate proteins
What are the start and end products of Glycolysis and how much ATP is extracted?
Converts one molecule of glucose to two molecules of pyruvate and generates two molecules of ATP
What happens in stage 1 of Glycolysis?
Stage 1 traps glucose in the cell and modifies it so that it can be cleaved into a pair of phosphorylated 3-carbon compounds
What happens in stage 2 of Glycolysis ?
Stage 2 oxidizes the 3-carbon compounds to pyruvate while generating two molecules of ATP
In stage 1, what does the enzyme Hexokinase catalyze? and is this favorable or unfavorable?
Glucose is phosphorylated at the expense of ATP to form glucose 6-phosphate
FAVORABLE
In stage 1,what does the enzyme phosphoglucose isomerase catalyze? And is this favorable or unfavorable?
Conversion of glucose 6-phosphate to fructose 6-phosphate.
NOT FAVORABLE
In stage 1, what does the enzyme Phosphofructokinase catalyze? And is this favorable or unfavorable?
Carbohydrate is trapped in the fructose form by the addition of a second phosphate to form fructose 1,6-Biphosphate
FAVORABLE
In stage 1, what does the enzyme Aldolase catalyze? And is this favorable or unfavorable?
It catalyzes the conversion of fructose 1-6-diphosphate to glyceraldehyde 3-phosphate(GAP) and Dihydroxyacetone phosphate(DHAP)
NOT FAVORABLE
In stage 1, what does the enzyme Triose Phosphate Isomerase catalyze? And is this favorable or unfavorable?
The conversion of Dihydroxyacetone phosphate (DHAP) to glyceraldehyde 3-phosphate(GAP).
NOT FAVORABLE
In the beginning of Stage 2, the oxidation of an Aldehyde powers the formation of which compound with High phosphoryl transfer potential?
1,3-Biphosphoglycerate
In stage 2, what does the enzyme glyceraldehyde 3-phosphate dehydrogenase catalyze? And is this favorable or unfavorable?
The oxidation of GAP which produces 1,3-Biphosphoglycerate
NOTE here NAD+ is consumed and it has to be regenerated if glycolysis is to continue
NOT FAVORABLE
IN the formation of 1,3-BIphosphoglycerate, what are the two steps that occur and why is an energy rich thioester required?
- Highly exergonic oxidation of carbon 1 in GAP
- Highly Endergonic formation of 1,3-Biphosphoglycerate from the acid
Energy rich thioester is required because the transition state free energy change is too large, and this will help reduce it
In the second step of stage 2, which molecule has a higher phosphate transfer potential; than ATP and what does the enzyme phosphoglycerate kinase catalyze? And is this favorable or unfavorable?
-1,3-Biphosphoglycerate has higher potential so it transfers the phosphate to ADP to generate ATP and the enzyme catalyzes this reaction
FAVORABLE
In stage 2, what does the enzyme Phosphoglycerate mutase catalyze? And is this favorable or unfavorable?
Conversion of 3-Phosphoglycerate into 2-phosphoglycerate
NOT FAVORABLE
In stage 2, what does the enzyme Enolase catalyze? And is this favorable or unfavorable?
a dehydration reaction that results in the production of Phosphoenolpyruvate from 2-Phosphoglycerate
NOT FAVORABLE