How does breaking ATP actually power reactions?


Every explanation I’ve seen for this doesn’t really explain how it works, just that hydrolyzing ATP releases the energy it has.

But how does that actually power the reactions in our cells? What type of energy is released and how does it work to move and make other molecules?

In: 12

The bonds in the phosphate group have a lot of energy because they are not very stable due to the close positions of the lone pairs on the oxygens. These lone pairs repel each other, so it’s basically a struggle for these phosphates to be in near proximity to each other and they can’t wait to be away. When the bond is broken, it is very energetically favorable (has a negative value of Gibbs free energy) and this energy that is released from bond breakage is used to push forward other reactions.

If you’ve ever played with magnets you should know that you can put them together the right way and they will stick (opposite polarities facing), or the wrong way and you will need to force them together otherwise they will snap away (same polarities facing).

ATP is like a pair of magnets forced to stay together with same polarities facing. When hydrolysis happens it’s like the force is released and the ATP molecule snaps! The snapping motion bumps nearby proteins, causing them to change shape, which dominoes into other molecules changing shape.

As far as I understand it, ATP can be built into other molecules where it acts like a one-shot fuel cell. The energy released would be of electrochemical nature and influence the surrounding molecule, causing atoms to attach or eject from another. This would either enable the synthesis of whatever the molecule is producing, or transportation, or fuel nerves.

There are several ways this happens, perhaps the most common is the ATP is being broken apart, and some portion of the two resulting molecules binds to the protein that broke it apart. This causes a change in the structure of the protein, something called a confirmational change. This change in shape of the protein then is able to induce the reaction of interest, like for example with the sodium-potassium pump [shown here]( See in the second step, it is the phosphorus being bound to the protein that causes the “Jaws” to swing shut.

Another way this happens is through the phosphorous binding to the molecule being acted on (called the substrate), as in the case with glycolysis (the metabolism of simple sugar molecules). In this case, the phosphorus is added on to the glucose, which then makes it easier to break apart the glucose molecule for energy.

A third way ATP is used to power things in your cells is similar to the first way, except the phosphorylation of the enzyme acts as a sort of on-off switch. The enzyme has no phosphorus attached to it, and is in its dormant state. Along Comes atp, which breaks apart and adds a phosphorus to the enzyme. This causes a change in the shape of the enzyme, confirmational change, which activates the enzyme and causes it to race around the cell and catalyze a bunch of reactions. Eventually, the phosphorus falls off of the enzyme, and it becomes inactive. This type of usage is commonly seen in signal transduction, or when a cell receives a signal on the outside and it starts doing stuff in response (like hormones or or insulin).