Question

how many net ATPs and NADHS are generated by the conversion of the following compounds into Lactate?

A. Glyceraldehyde in the liver

B. Dihydroxyacetone in the liver

Answer 1

A. Glyceraldehyde 3 phosphate is converted to 1,3 bisphosphoglycerate with the formation of 2 molecules of NADH. 1,3 BISPHOSPHOGLYCERATE is converted to 3 phosphoglycerates with the formation of 2ATP. Finally, the conversion of 3 phosphoglycerate to pyruvate through two more steps helps in the formation of two molecules of ATP. Thus net molecules of ATP formed from glyceraldehyde 3 phosphate to pyruvate are 4 and 2 NADH. Formation of 2 lactate from 2 pyruvate results in the consumption of 2 NADH. Thus overall -

Net ATP yield- 4

Net NADH yield- 0 as 2 NADH used and 2 NADH formed.

B. Similar is the case with dihydroxyacetone phosphate as in the glycolysis step it is converted into glyceraldehyde 3 phosphate which joins the glycolysis.