What's the point of gluconeogenesis? Isn't it taking 2 steps forward, 4 steps back

Glycolysis: 2 ATP arise from this process. Hooray you have energy.


but uh oh, my blood glucose is low. No matter, GNG will make some more glucose for me. So I use 6 ATP to produce glucose... that glucose is used to... produce 2 ATP? Perhaps I'm missing the point of producing glucose when blood glucose is low

You're right - there's a net energy loss from it. The problem is that a lot of our cells (most importantly, brain cells) can only use glucose. It doesn't matter how much fat or protein there is to burn - if we run out of glucose, then our brains shut down. That's why we use gluconeogenesis. It's not very efficient, but it keeps us alive.

It might seem easier for evolution to simply give our neurons the ability to metabolize lipids or proteins. Unfortunately, the brain is very fragile, and can't deal with the metabolic by-products of other energy sources. In a sense, it's like a high-powered engine that can only run on high-grade fuel, which in this case, is glucose.

he pathway leading from pyruvate to glucose-6-phosphate requires 4 molecules of ATP and 2 molecules of GTP. Gluconeogenesis is often associated with ketosis. Gluconeogenesis is also a target of therapy for type II diabetes, such as metformin, which inhibits glucose formation and stimulates glucose uptake by cells

I dont get what you are saying. Gluconeogenesis isnt the only way for us to get Glucose. The body only uses it when we are low on glucose. Someone who hasnt ate for example will make glucose through gluconeogenesis otherwise we get it from food.

They both dont happen simultaneously. Only when Glucose levels are really low does it happen. So in effect we can create many atp through glycolysis before we need gluconeogenesis to occur.