- [Voiceover] The fourth of the major macromolecules
is gonna be nucleic acid.
Now there are two primary types of nucleic acids.
You have DNA, or deoxyribonucleic acid,
and you have RNA, ribonucleic acid.
Now you notice both of them have the term ribonucleic acid,
just DNA has deoxy.
Reason being, deoxy, without oxygen.
There's one less oxygen molecule in DNA.
But both these are meant to store genetic information.
The DNA is primarily located within the nucleus of a cell.
It's kind of the brain of a cell,
the main structural point of the cell.
It contains all this genetic information,
controls what's going on.
While the RNA can be found it the nucleus,
but it can also be found throughout the rest of the cell.
It's these two nucleic acids that are used
to provide information to make a protein.
Well if you're wondering what's protein do in our bodies?
All your muscles are tons of protein,
bones, most of your organs,
your skin, the vast majority of tissue in your body,
that's structural tissue, is going to be protein.
Now these nucleic acids, doesn't matter if it's DNA or RNA,
they are long chains that just keep going one after another.
What they're doing, is they're repeating these sub-units,
basic building blocks referred to as nucleotides.
Now DNA has four primary nucleotides.
The same thing with RNA.
The only difference is they don't quite have the same four.
These nucleotides are the building blocks.
It's long chains of these nucleotides
that make up the nucleic acids.
Now the nucleotide is made up of three primary components.
You have a five carbon sugar.
Now this five carbon sugar will be dependent
on DNA or RNA.
If you're looking at DNA, this sugar is deoxyribose.
If you're looking at RNA, it's ribose.
Both deoxyribose and ribose are your simple sugars.
Those are monosaccharides from your carbohydrates.
Then you have a nitrogenous base
and a phosphate group.
Now the sugar and phosphate group
are always the same in DNA or in RNA.
The way you get different types of nucleotides
is by changing the nitrogenous base.
There's a total five different types of nitrogenous bases
found between DNA and RNA.
In DNA, we have these four nucleotides.
We have the difference being nitrogenous base.
On the left, you can see is Adenine.
Kinda has a little green shading there.
Now the colors mean nothing.
They're just given you there for illustration purposes.
But Adenine, making that one type of nucleotide.
Then Thymine, Cytosine, Guanine.
Those are the four different types of nucleotides for DNA.
So the structure of DNA,
using those four different nucleotides,
build up all of the nucleic acids of DNA.
The deoxyribonucleic acid is double-stranded.
That means there are two strands of DNA
that are always being held together.
And we already said Adenine, Guanine, Cytosine, Thymine,
those are the four different nitrogenous bases.
With a deoxyribose sugar.
And when they start pairing,
it's always Adenine, Thymine,
Guanine, Cytosine.
So it's always A and T, C and G.
If for some reason you end up with an A bound to a C,
or a G bound to a T, that's an error.
That could potentially cause some pretty serious problems,
even with one little mix up.
So your body, thankfully, is pretty good
at making sure it doesn't produce errors.
If it does produce an error,
there's special mechanisms to catch or correct errors.
So here's a artist's rendition of DNA.
Towards the top of the picture,
you can see how it's spiraling, creating this helix.
Or this double helix.
Towards the bottom, they flattened it out,
just to show how things are going together.
You can see the base pairs.
C, G, T, A,
A, T, C, G.
They're always in the middle of a double strand.
While the outside edges, see all the purple area,
phosphate, sugar, phosphate, sugar.
Alternating.
So you can kinda think of it like a ladder.
The rungs of the ladder are the base pairs.
Those nitrogenous bases.
While the outside edge of the layer
that hold the rungs together
is alternating sugars and phosphate groups.
And this is the basic idea for all DNA.
Now to have DNA be different,
you'd change up the base pairs.
Those nitrogenous pairs.
Because as you read DNA, it's like reading a sentence.
You read them in order.
Depending on the order,
depends on what protein will be produced.
So how about some RNA?
RNA is ribonucleic acid.
Same basic principle as DNA,
but now we're only single-stranded.
So instead of that double strand we had in DNA,
we have a single strand in RNA.
The sugar is ribose instead of that deoxyribose.
So RNA has ribose.
And it still has Adenine, Guanine, Cytosine as the bases,
but now it added Uracil.
Uracil is only found in RNA.
You cannot find Uracil in DNA.
So which nitrogenous base is only found in DNA
and not in RNA?
Remember in DNA, it was C binds to G,
Cytosine, Guanine,
A binds to
T, Thymine.
So Thymine is only in DNA.
Well Uracil is only in RNA.
And here's a strand of RNA.
You can see it's the same thing,
just looks like half of a DNA strand.
You have nitrogenous bases on one side.
Then you have this back bone
alternating sugar, phosphate, sugar, phosphate.
It's going phosphate, ribose, phosphate, ribose,
phosphate, ribose.
So same basic layout, just a few different components.
We have ribose, for sure,
and we have Uracil as a base.
So we already mentioned that they store genetic information.
But why do you need two different types of nucleic acids?
Why DNA and RNA?
Well the reason being DNA stores instruction in the nucleus.
It's kind of like the memory center.
It keeps the information in every cell.
But DNA cannot leave the nucleus.
It can't do anything.
It's stuck in there.
So DNA will help make instructions for RNA.
RNA then will carry those instruction from the nucleus
out to the rest of the cell.
When it carries it out to the rest of the cell,
it can initiate the making of proteins.
Cause remember, ultimate goal here was to make proteins
for structural components of the body.
Protein, that's what makes our life go on.
It's things that give us structure.
Proteins can help with different chemical reactions.
Proteins can take part in a majority of what our bodies do.
So this DNA to RNA to protein
is always found in that sequence.
DNA cannot directly make protein.
That's why RNA is so important.
It bridges the gap between the DNA and the protein.
So DNA to RNA, RNA to protein.
And that little passage right there is very, very important
as far as how our bodies work.
Because without the DNA, you can't make the RNA.
Without RNA, you can't make protein.
So DNA to RNA to protein.
But then we have some of this not really a nucleic acid,
but it looks very similar.
We have ATP.
Adenosine triphosphate.
Now, think Adenosine.
That was one of those bases.
That's right.
Adenosine was a nitrogenous base.
What we've done now is taken that Adenosine nitrogenous base
and attached it to three phosphates.
Hence the term triphosphate.
ATP is the energy source for your cells.
Now do you eat ATP directly?
No, not really.
You eat carbohydrates, lipids, proteins, nucleic acids.
But your body takes that fuel that you eat
and converts it into ATP.
Because ATP is what the cells of your body
can utilize for energy.
It's the bonds that are made.
So you have three phosphate groups.
The bonds between each of the phosphates
contain potential energy.
Oh think, okay, potential energy, potential energy.
Potential energy is stored energy.
Kinetic energy is the energy of movement.
So these bonds are storing potential energy.
When you break a bond, you release energy.
So ATP, adenosine triphosphate,
can go to ADP plus P.
So it's the extra phosphate.
You've broken one phosphate off.
By breaking that phosphate, you released energy.
That released energy can perform work inside the cell.
Here's a schematic of that process of releasing energy.
Now we take ATP, adenosine and three phosphates,
then add water.
Why do we add water?
Remember, if you add water to break a bond,
it's called hydrolysis.
Hydro, water, lysis, break.
So by simply adding a water molecule,
we can break the bond.
By breaking that bond, it releases energy.
And we end up with adenosine diphosphate, ADP,
and extra phosphate floating around.
But that's not quite as useful in your body.
So somehow you have to now obtain more energy.
You obtain more energy to put that phosphate
back on to the ADP molecule.
So come from energy that's stored in your body.
Glycogen, storage of carbohydrates.
Or fat, storage of lipids.
If you take any one of those energy storages,
break them down a little bit to release energy.
That energy will go into putting the phosphate
back into ATP.
But that, well, now what you're doing,
by actually adding energy, you remove water.
When you remove water to form a bond,
that's dehydration synthesis.
So the foods you've eaten will provide the energy
to make the bonds of ATP.
So that can store the energy to be used
when the cell is ready.
And it's all a continuous cycle.
Your cells use energy.
You ingest food to gain energy.
You make more ATP.
The body uses more ATP.
So a constant overall circle.
You add energy, subtract it, add, subtract it.
As long as your body's functional,
you have to go through this on a daily,
hourly, minute by minute basis actually.