Glycolysis Flashcards
(14 cards)
- What cell surface protein regulates uptake of glucose from the circulation?
Glucose transport protein 4
- What is the first chemical reaction involving glucose when it first enters the cell?
Phosphorylation at carbon-6 by a phosphate ester involving ATP and the C-6 hydroxyl group
- Which enzyme of glycolysis catalyzes this first reaction?
Hexokinase
- What is this first reaction classified as regarding the rate of the glycolysis reaction pathway?
Hexokinase catalyzes that rate limiting step of glycolysis - step 1
- In what part of the cell do the reactions of glycolysis occur?
Cytosol
- The enzyme type, kinase, is involved in several important reactions in the cell. Generally, what is the reaction that is catalyzed by all “kinase” enzymes?
Phosphate transfer involving ATP
- After the first reaction involving glucose occurs, what is the significance regarding maintaining glucose in the cell?
The phosphorylated glucose cannot leak back out of the cell through glucose transport protein
- As a matter of glucose structure, the first reaction involves carbon number 6. The alcohol at carbon 6 is not within the ring structure of glucose. Based on this structural characteristic, why
would converting glucose phosphate to fructose phosphate be significant to phosphorylation of fructose phosphate?
With the Fructose structure, carbon-1 hydroxyl is NOT within the ring structure so it is a better substrate for phosophofructokinase
- How many ATP are used in the first half of glycolysis?
2
- When Fructose 1,6-bis phosphate is “split” which of the two 3-carbon products is the structure that proceeds through to the end of glycolysis?
G-3 Phosphate -
The other 3-carbon structure, dihydroxyacetone phosphate is converted to G-3 phosphate
- Which step in the glycolysis pathway represents the “committed” step?
Phosphorylation of Fructose 6-phosphate, so phosophofructokinase catalyzes the committed step- step 1
- When Glyceraldehyde 3-phosphate is phosphorylated to 1,3-bisphosphoglycerate there is an oxidation reaction coupled to it where NAD is reduced to NADH. If the cell type is anaerobic how does this reaction provide significance to the conversion of pyruvate to lactate? In other words, if glycolysis in anaerobic cells, what is produced from pyruvate and why?
In the anaerobic cell NAD is limited- by concerting pyruvate to lactate, NADH is oxidized, thereby regenerating NAD so that glycolysis can continue
- For each glucose molecule that is metabolized by glycolysis, what is the net production of ATP?
2
- If the cell type is aerobic, what happens to the pyruvate?
It will be transported into the mitochondria where it will be completely oxidized
