Glycolysis: 1,3 BPG –> 3-PG – Glycolysis and Pyruvate Metabolism

00:00 The next reaction of the pathway is where we start to create ATPs.

00:06 In this reaction 1,3-bisphosphoglycerate is converted into a molecule called 3-phosphoglycerate, and this is a pretty straight forward reaction.

00:15 You see the phosphate on position 1 on the left being removed and transferred to ADP to make ATP by the enzyme phosphoglycerate kinase.

00:25 Now this reaction is interesting in the sense as what we call a substrate level phosphorylation.

00:33 A substrate level phosphorylation occurs when a high energy molecule transfers a phosphate onto ADP to make ATP which is exactly what you have seen here.

00:44 Now many people think mistakenly that this is the way most ATPs is made in the cell, by simply having a high energy molecule to transfer.

00:54 It doesn't occur that way. And in fact most of the ATP in cells is made by a process called oxidative phosphorylation.

01:01 This is an unusual reaction in a sense that ATP is made directly.

01:07 We will see another one of those later in glycolysis.

01:09 The delta G zero prime for this reaction is very energetically favorable, meaning -18.9 kJ/mol. It moves very strongly to the right and since we are making an ATP what that tells us is that there is a lot energy in 1,3-bisphophoglycerate in order to make this happen so efficiently.