Why is ATP the energy molecule in the cell instead of glucose?

Question

Why is ATP the energy molecule in the cell instead of glucose?

Answer 1

There are a few key reasons why ATP is used in cells.

ATP is a small unstable molecule that readily released stored energy by hydrolysis of one phosphate.  It can be easily regenerated from ADP by the addition of one phosphate.  One ATP-->ADP reaction only releases a small amount of potential energy which limits energy waste.

In truth you could use any small readily hydrolyzable molecule to store energy in this way.  Like ATP, the cell would just have to keep the concentration of the unstable molecule (ATP) high in comparison to its more stable form (ADP) thus creating potential energy in the cell that can be used to do work.

ATP does not store that much energy, and there are definitely molecules which store more energy than ATP, but it  requires more energy expended by the cell to get at it.

Glucose is a good example of this.  The amount of energy stored in glucose is used to make 36 ATP through glycolysis and electron transport.  Since the bonds in glucose are not unstable and thus not easily hydrolyzable glucose is not a suitable molecule for the purpose of powering reactions in the cell.

Answer 2

ATP is a simpler unit

Answer 3

The reason is because ATP has three (although only one is typically used) phosphodiester bonds.  A lot of energy is given off when this bond is broken.  The bonds in glucose don't have this much energy.

Answer 4

because your body breaks down glucose and uses it to make ATP...the reason why they say ATP is and glucose isn't is becuase you can make ATP with fat and protein as well..glucose isn't a requirement