Exam 2_Structures and Processes Flashcards
What are the 3 possible fates of pyruvate after it goes through glycolysis? draw the structures of each product
Become…
- Ethanol (via Fermentation)
- Acetyl CoA (via Complete Oxidation)
- Lactate
Draw the 1ST and 2ND STAGES OF GLYCOLYSIS. Include the intermediate compounds, enzymes, and products.
Draw the 3RD STAGE OF GLYCOLYSIS. Include the intermediate compounds, enzymes, and products.
Draw and describe what an ALDOL CONDENSATION RXN is. Include the products formed, all structures, and electron movements.
Forms C-C bonds
Products: β-hydroxy aldehydes or ketones
“insert aldol condensation mechanism from ch 16 notes pg 2)”
Draw and describe what an RETROALDOL CLEAVAGE RXN is. Include products formed, all structures, and electron movement/mechanism.
It is the reverse rxn of aldo condensation
Product: cleaved β-hydroxy aldehydes or ketones
“insert retroaldo cleavage mechanism from ch 16 notes pg 2”
Describe the isomerization step of glycolysis (step 2).
- what are the start and end products?
- what rxn is involved?
- what happens?
- draw the mechanism
Start Product: Fructose 1,6-biophosphate (F-1,6-BP)
End Product: Glyceraldehyde 3-Phosphate (G3P)
Rxn Involved: Retroaldol Cleavage
What Happens: C-C bond is broken and ring is opened
Mechanism: “insert mech. from ch 16 notes pg 3”
Draw the mechanism of the 2nd step of stage 1 (isomerization by phosphoglucose isomerase) in glycolysis. Include all structures and electron movement.
“insert mechanism of isomerization by phosphoglucose isomerase from pg 4 of ch 16 notes”
Draw the mechanism of the 3rd step of stage 1 in glycolysis (2nd phosphorylation by PFK). Include all structures and electron movement.
“insert mechanism of PFK catalyzed phosphorylation (ch 16 pg 4”
Draw the mechanism of the 4th step of stage 1 of glycolysis (aldolase catalyzed retroaldol cleavage of fructose 1,6-biphosphate). Include all structures and electron movements.
“insert aldolase catalyzed retroaldol cleavage mech pg 5 of ch 16 notes”
Draw the mechanism of the TIM catalyzed isomerization of DHAP that’s done in glycolysis. Include structures, residues, and electron movement.
Draw the mechanism of the GAPDH (glyceraldehade phosphate dehydrogenase) catalyzed coupled rxn of G3P/GAP to 1,3-BPG (1,3-Biphosphoglycerate). Include all structures, side products, and electron movements.
Why are the oxidation and phosphorylation steps coupled in the GAPDH catalyzed rxn of G3P to 1,3-BPG?
Because if they’re separate, the activation energy barrier is too high so rxn would occur too slowly. To make faster, phosphorylation is coupled to the oxidation of G3P by a thioester intermediate.
Draw the catalyzed rxn of 1,3-BPG to form ATP. Show all structures involved and the enzyme used.
What are the intermediates, enzymes, and mechanism of the conversion of 3PG (3-Phosphoglycerate) to Pyruvate?
Write out the net reaction of glucose into pyruvate. Include all starting materials and end products. No mechanisms, structures, electron flow or intermediates needed.
Write out the steps of ethanolic fermentation. Include all intermediates, enzymes involved, and start/end products.
The Zn(II) ion in alcohol dehydrogenase activates the acetaldehyde carbonyl to accept hydride (H-). *Zn(II) does this by pulling electron density away from the carbonyl carbon to make it better at receiving proton (H+) from NADH.
Write out the steps of homolactic fermentation. Include start-end products, enzymes, and intermediates if any.
