Up Learn – A Level Biology (AQA) – Respiration
Glycolysis: Production of Glucose Phosphate
Glycolysis begins with ‘phosphorylation’, a process that results in glucose phosphate.
This is then converted into triose phosphate and, from there, pyruvate.
We’ve seen that during glycolysis, a molecule of glucose is converted into two molecules of pyruvate.
Now, getting from glucose to pyruvate isn’t actually one simple step…
…in fact, there are a set of complex reactions involved!
At A level, these many stages of glycolysis are condensed down into 3 steps
And in this video we’ll focus on the first step, which transforms the glucose molecule into something new.
So, when glucose enters the cell’s cytoplasm, an enzyme in the cell adds two phosphate groups to it.
This process of adding phosphate groups to glucose is called phosphorylation
And it results in a new molecule called glucose phosphate.
So, the first stage of glycolysis is phosphorylation, which turns the glucose molecule in the cytoplasm into glucose phosphate!
Next, these phosphate groups are available due to the breakdown of 2 ATP molecules:
Each ATP molecule donates one phosphate to the glucose, and the loss of phosphate turns the ATP molecules into ADP.
Now, this might seem a bit strange, since the whole point of respiration is to make ATP…
But don’t worry!
By breaking down two ATP molecules here, during glycolysis, we’re setting up what we need in order to produce a ton more ATP molecules after glycolysis!
To sum up, when glucose enters the cell’s cytoplasm…
When glucose enters a cell’s cytoplasm, an enzyme adds two phosphate groups to it…
Producing a new molecule called glucose phosphate.
These phosphate groups are available due to…
These phosphate groups are available due to the breakdown of 2 ATP molecules