- [Voiceover] When we study science it's natural to
just categorize a whole series of things as just
being really really unimaginably small.
So when people say, hey atomic scale,
or molecular scale,
or protein, or cell,
you often just group that together and say
oh, those are really really really
really small things.
But what I want to do in this video
is get an appreciation that even though
all the things I've just mentioned are really small,
there's actually a huge difference
in the sizes of those things.
And hopefully that'll give us an appreciation
for how complex something like a cell can be.
How it can have all of this machinery.
How it can actually be a living organism
or part of a living organism.
And so at this scale this is a
this is my little rendering,
my drawing of a water molecule.
You have the oxygen atom in the right over here
in this purplish color,
and then you have two hydrogen molecules
bonded to it.
And this is going to be roughly
0.275 nanometers.
And just to remind ourselves,
a nanometer is a billionth
of a meter.
And just to get an appreciation of that
so let me.
So this is
one billionth
one billionth of a
one billionth of a meter.
That's a nanometer.
And if you want to even attempt
to visualize that
that would be a millionth
of a millimeter.
So one, let me write this.
One one millionth
one millionth
of a millimeter.
And I actually like using this one
because a millimeter is
about as small as I can
on a reasonable basis visualize.
But instead of a millionth of that
it goes well beyond, at least my capabilities
of visualization.
So that would be the diameter
or the width of a water molecule.
But now let's go to the next scale up.
We've talked a lot about proteins
and this is our friend,
this is right over here is
our friend hemoglobin.
And this gives you a sense of scale,
the width of hemoglobin is going to be
about five nanometers.
Or five billionths of a meter.
Now that seems super small,
so in some ways it's okay to categorize
that into your super small part of the brain.
But it's good to appreciate,
this is much larger than a water molecule.
If a water molecule were on this scale
I predrew it, this little thing
over here, that's my attempt
at drawing a water molecule
at this same scale.
So even when you go from something
like a water molecule to a protein
you're already going dramatically up in size
and dramatically up in complexity.
And we've talked a lot about protein structure
and how they can take on all of these
interesting shapes, and do fairly
surprising and complex things
inside of biological systems.
But now let's go,
let's go the next scale up.
And the next scale up
I'm gonna go to a virus.
And what I've attempted to draw here
this is a fairly well known virus,
this is HIV.
And it's actually one of the larger viruses
and its diameter is roughly
120,
120 nanometers.
So if we were to
draw this hemoglobin
this hemoglobin protein at the same scale
as we've drawn this virus
this thing right over here
would be the hemoglobin protein.
And we wouldn't even be able to see
the water molecule at this scale
right over here.
But this is still really really small.
This is 120 billionths
of a meter.
So this is still
this is still unimaginably small.
But now let's go up to the,
let's go up to the next scale.
So this creepy picture
right over here,
this is a T-cell.
This is a depiction
this is a, if you want to see
the whole thing,
that is a T-cell right over here.
This is a T-cell.
And this creepy picture,
this all the blue,
that's the T-cell.
And what you see in yellow
that's the HIV virus emerging,
taking advantage of this T-cell.
So, that's why it's so creepy,
it's using that cell's machinery
to reproduce itself.
But you immediately see on this picture
how small the HIV virus is
compared to the actual T-cell.
Each of these small little things
each of these small things,
is an HIV virus, which we already saw
is a lot bigger than something like
a hemoglobin protein.
And so a hemoglobin protein
you wouldn't even be able to
on this scale, maybe
it would be a pixel,
if that.
And on a similar scale, is this T-cell,
you have a, you have things like red blood cells.
This is actually a comparison
this side by side.
This is using an electron,
this is using an electron microscope
you see a red blood cell right over here
and you see a T-cell
and they're roughly roughly
on the same size,
or at least the same order of magnitude size.
And a red blood cell is going to be
six to eight micrometers,
micrometers wide.
So this is six to eight millionths
of a meter.
So if we were to
if we were to just take seven
as the average.
Seven millionths,
seven
seven millionths
of a meter.
Over here, we're talking about
a millionth of a millimeter.
Now we're talking about seven millionths
of a meter.
And just to get an appreciation for size,
we already compared the virus,
the HIV virus, to this cell.
We're seeing it directly
as a emerge from the cell.
But each of these red blood cells
are gonna contain roughly
280 million hemoglobin molecules.
So there's gonna be 200
each of these there's gonna be
280 million of these.
So 280 million,
that's a million
million hemoglobins
in each one of these.
So hopefully this starts to give you
an appreciation for
even though we categorize cells
as these unimaginably small things,
they're actually far larger
they're ginormous compared to things
even like even like large even proteins.
And especially when you think of things
on the molecular, or the atomic scale.
And that's why cells are so interesting.
They actually have a lot of
complexity to them.
But just to have an appreciation also
for how small cells are
even though we've just described
these red blood cells and these T-cells
there's these kind of worlds unto themselves.
They are these incredibly complex things.
If I were to draw the width
of a human hair
on this screen right now
relative to the scale
of these red blood cells,
it would be about as wide as this video.
So from if I were to draw a human hair
it would go from there roughly to there
and there's actually a lot of variance
in the width of a human hair.
But the width of a human hair would be
just about like that.
If you looked at the scale of
if you looked at the scale of
this picture right over here.
If you looked at these scales
it would be much much much bigger.
And I encourage you
we can think, oh okay,
the width of a human hair.
Pluck a hair out.
Look at it.
Put it on a piece of paper.
It's hard to even discern the width.
But we're saying that that width
compared to these red blood cells
would actually be your entire
width of the screen.
We've already said these red blood cells
these T-cells, these are kind of
these are worlds unto themselves when you think of it
from a viral, or especially at a molecular scale.