DNA replication exergonic/endergonic?

[HopefulMDclass2020]

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I was wondering if DNA replication exergonic/endergonic. Generally, I think anabolic processes are endergonic, however we know that the hydrolysis of the pyrophosphate from each dNTP is the driving force. Does this make it exergonic?

Thanks

 

[Axes]

Definitely endergonic..otherwise why bother with cell respiration? 😉

edit: more seriously though, think of the enzymes and whatnot involved. They all need energy to function. Basically your initial thought was correct, anabolism is typically endergonic

 

[RH8448]

The nucleotides have to be reactive in order to make that phosphodiester linkage. The 3' of the ribose molecule is a nucleophile and essentially attacks the first phosphate on the next nucleotide as a nucleophile. The leaving group is the pyrophosphate. So, these molecules have both nucleophiles (alcohol 3') and electrophiles (the first phosphate group). These are energetic molecules. However, we are organizing them into DNA which decreases entropy. We need an enzyme like DNA polymerase to catalyze this. The hydrogen bonds that form between the bases helps make this favorable.

These energy molecules (dnTPs) are not for free, however. They come from the pentose phosphate pathway starting with glucose!

 

[HopefulMDclass2020]

Thank you all! Great responses 🙂