ATP is another thing that we should probably review
because it is the energy currency of cells.
We've already seen ATP and another energy molecule
in the form of GTP
so instead of adenine we would use guanine
attached to the ribose-3-phosphate.
But ATP is the primary energy molecule.
All of these nucleotide triphosphate could work in the same way.
We have the core of it, which is adenosine monophosphate. And then
as we add phosphate onto those, we can have adenosine diphosphate
and adenosine triphosphate. So ADP, ATP and AMP. Previously
we've seen cyclic AMP, that's just this molecule with one phosphate.
Right. And that was as the second messenger.
So when we consider ATP,
we can either add phosphates or remove phosphates.
And as we remove phosphates, we release energy,
as we add phosphates, we are consuming energy.
So an exergonic and endergonic reaction respectively.
In this system, we can take energy from exergonic cellular reactions
and store them in the form of ATP
which is what we do in the process of cellular respiration,
a little bit of water is generated, we'll track that down later.
And then we can use the energy stored in ATP to fuel
all of our reactions are energy requiring or endergonic reactions.
When we do that, we cleave a phosphate off, the general practice
is that we take one phosphate off although sometimes we take off two
and get a little bit more energy, but mostly we just take off one
and create ADP which can then go around and pick up more phosphates
so on and so forth. So this is a cyclic pattern of ATP
being created from fuels that we consumed
and then being released to run all over other cellular processes,
a lot of which we've already looked at.
We require ATP for everything that goes on inside the cell,
for example in cell division or in cell communications.
ATPs are phosphorylating things, right.
So ATP is the energy currency.