Biologists say that breaking a chemical bond (e.g. ATP -> ADP + P) "frees energy" and there's "much energy stored in bonds". However, in chemistry, it is known that formation of a bond frees energy and breaking a bond consumes energy.
What's the reason for this?
It depends on where you’re looking for the energy
As I understand it, phosphate bonds "release" energy because ADP + Pi has less enthalpy, phosphates which are very electronegative require a bunch of energy to be clumped together inside of the ATP molecule, and when they're separated the thermodynamic system releases that energy (see: definition of enthalpy)
...and this is the enthalpy of the reaction
My wording is almost as shit as my vague understanding, I meant "electron-dense" and not electronegative
The reason that biologists claim that breaking bonds free energy is because they think that's an easier concept for students to understand. From a very literal view, the chemists are right and the biologists are, at best, being deceptive
the potential energy released freeing one phosphate from its position next to the other two phosphates is greater than the energy consumed breaking the bond between the phosphate groups
>in chemistry, it is known that formation of a bond frees energy
Not true for endothermic reactions
It depends on the reaction.
Bonds always contain energy.
Breaking a bond always releases that energy
It is literally not possible for the breaking of a single bond to be net endothermic.
More realistically, a bond is not a physical object that can be broken or created. It represents an electron orbital shared between two atomic nuclei. For such a state to occur, it /must/ be lower in energy than the corresponding two unshared orbitals which are present in the absence of a bond. If it were higher in energy it would not be thermodynamically stable; it would disocciate fairly instantaneously.
This is all covered in molecular orbital theory in chem 1 which im pretty sure all stem undergrads have to take.
Here, in reference to your biology example, ATP + H2O -> ADP + P is not just the breaking of a single bond. The reactants transition from a high energy state to a relatively low energy state. The overall energy stored in bonds on the right side of the equation is lower than that of those on the left.
If you are really interested you can look up the reaction mechanism which shows how the electrons move in the formation of products
Breaking bonds requires raw kinds of energy like heat (which is movement) or electricity. It also often results in the excess energy going places where we can actually see and use. Essentially, chemicals store energy by making it less useful, or just less in general.
Breaking bonds only releases energy when what you use to break the bonds is a better oxidizer or reducer than whatever it was bonded to. Tell me how you're supposed to get any energy out of breaking the ionic bond in cesium fluoride.
The body does not actually metabolize the energy directly from broken bonds. Rather, the new components, particularly the phosphorus, is taken up by various proteins in mitochondria altering their shape and allowing them to function. Most of our energy is actually derived from an ionic imbalance of Hydrogen within the mitochondria. This imbalance is maintained by proteins which use Phosphates to function. I am however almost fairly certain that ATP contains more energy than ADP and Phosphorus.
For the first time I came to understand (on my own without being told it) that Veeky Forums is just freshmen and high schoolers. Thank you thread
>CsF
>Enthalpy of formation ~ -500 kJ
The system is in a lower energy state when theres a bond. In order to break the bond, you need to add 500 kJ of energy to the system in order to effect a positive increase in enthalpy from -500 kJ to 0 kJ.
Therefore at the end of the reaction
CsF->Cs+ + F- the reactants are in a higher energy state.
Like I said there are literally no counterexamples to this
Whether or not you can "get" energy from a reaction is a question of the Gibbs free energy
> If it were higher in energy it would not be thermodynamically stable; it would disocciate fairly instantaneously.
Lol, what are chemical kinetics? I genuinely hope you're not actually studying at university. If you are, drop out immediately, you're not going to make it.
This post reads like an ugly amalgamation of youtube and khan academy videos digested through the brain of a brainlet.
It's been this way for a couple of years.
>This post reads like an ugly amalgamation of youtube and khan academy videos digested through the brain of a brainlet.
but isnt that a good thing?
Neutrons are a hoax.
Pretty sure Quantum physics is a hoax as well.
Its fucked up.
Gravity is a hoax force too.
The Earth is a fixed plate, and protons and electrons are all there is.
No
Are you kidding me? I thought Veeky Forums has only academically accomplished people with high IQ and well-received publications.
I fucked up my original post, meant exothermic instead of endothermic
anyway find me one example where the bound state is higher in energy than the unbound state for an otherwise equivalent set of atoms/ molecules
It's frees synergistically enslaved energy to be metabolized, you may be semantically correct at the scale of a chemical bond. But not at the scale of analysis of which biology is concerned, a chemical bond as a component of a living system.
I have virtually no understanding of chemistry or wee little biology, and this is obvious.
Why are the qualities of life itself so elusive to you people? Why is it so hard for reductitards to conceptualize complex systems?
>Bonds always contain energy.
>Breaking a bond always releases that energy
>even refers to endothermic reactions
It seems to me that you're just uneducated or extremely confused.
>If it were higher in energy it would not be thermodynamically stable
Second law of thermodynamics, you stupid prick.
>find me one example where the bound state is higher in energy than the unbound state for an otherwise equivalent set of atoms/ molecules
Google endothermic spontaneous reactions.
Saged, reported, hidden.
>Most of our energy is actually derived from an ionic imbalance of Hydrogen within the mitochondria
which is used to make ATP
>This imbalance is maintained by proteins which use Phosphates to function
it's maintained by proteins involved in glucose metabolism
Sure, there are spontaneous endothermic reactions. But none of them are addition reactions. There is literally no way for the formation of a stable bond to consume energy.
>if it were higher in energy it would not be thermodynamically stable
Again, literally find one example where the bound state is higher in energy
bond formation enthalpy =/= reaction enthalpy
Could you please tell me that mitochondria are the powerhouse of the cell, too?
But they teach it in cell biology. And what they teach is wrong.
If this was true all diamonds would spontaneously convert to graphite.
ur wrong
This is just an easy way to explain it to high students.
The best explanation is that the last phosphate has a high tendency to leave the ATP. This can be seen as "potential energy" for other enzymes to do work. and tons of enzymes use ATP in cells. In that frame of reference, it can be seen as the ATP being "energy storage."
No they do not. They teach you that the hydrolysis of ATP is thermodynamically favorable but kinetically stable.
If your biology program does not teach this, it must be shit.
In my programme they literally said "breaking a bond frees energy".