- Photosystem I coming at you.
First of all I mean
photosystem II coming at you.
First of all I have a little
visual here for you
of an actual chloroplast.
This is an actual thylakoid
and you can see
that it£s made of cell membrane
and these are my photosystems
that are embedded
in the membrane.
And so I just wanted you to have
a sense of what they
actually truly look like.
Instead of just the windified
version which that£s okay.
We£re going to do the windified
version too.
Here£s the scoop.
Are you ready for the madness?
Of course you are.
The scoop is that I£m going to
have my thylakoid membrane
down here at the bottom.
This is my outer thylakoid
membrane
and this is my thylakoid space.
Thylakoid--seriously.
That£s going to be important.
And this out here is my stroma
and I£m going to draw you
my photosystem I.
And it looks just like I showed
you because I£m a nerd
and that£s just how
my brain works.
And no picture of photosynthesis
is complete without a sunshine.
And there£s my little sunshine
shining down light
onto photosystem dang it.
It's not photosystem I.
It£s photosystem II dog pounds.
Look over here the menu says
photosystem II.
No matter what I say this is
photosystem II.
Here comes the energy.
Now I have to pick the right
color yellow all over again.
Down comes light energy like
a little fairy godmother.
But I forgot to tell you like
what is the point?
This is going to blow your mind.
Guess what is in the core of
photosystem II?
Like at the base there
are electrons
and there are two of them.
And they£re just chilling.
What? They are? Yes.
They£re just hanging out there
and everything about the
photosystem funnels energy down
to make them
what do you suppose?
High energy electrons seriously.
And this is where it becomes
even more like a trampoline
because the energy from the sun
comes down funnels down
and the photosytem, all the
proteins in the photosystem
are funneling the light to these
two electrons.
So all this energy
is like getting them
all kind of fired up and they£re
getting kind of crazy
and pretty soon, no joke, they
get flung up into the air.
They are like two
up in the air electrons.
Now tell me what kind of
electrons are they?
How about high energy electrons,
dog pounds? It£s true.
They are. They£re now high
energy electrons.
How did they get high energy?
They collected the energy from
the sun as opposed to
the high energy electrons in
cellular respiration,
where did they get their energy?
From glucose, from
the chemical bonds in glucose.
So now we've got
high energy electrons.
Thank you very much,
Mr. Sunshine.
And what do you think
we£re going to do with them?
How about--what is this?
Why not?
Let£s throw an electron
transport chain into the mix.
And so these little electrons
get passed down
to an electron transport chain
and they£re
high energy electrons.
So they£re going to do exactly
what they do
in cellular respiration which
is what?
Yes. They£re going to pump
protons
into the thylakoid space.
Can you see why this is old
school? We got this.
What are you talking about,
Willis?
We£ve been here.
Done this before.
Now what are we
going to do with them?
We know exactly what we£re going
to do with them.
We£re just reviewing now.
This is ridiculous.
Let£s pass them down.
Let£s grab some of the energy
from those high energy electrons
and let's use that energy to do
a little pump, pump,
pump, pump, pump action.
And pretty soon we£ve got an
amazing like collection
of protons.
We£re creating a concentration
gradient, true story.
Keep passing these puppies
along. Why not?
Keep pumping. Why not?
Why? Why pump?
There£s a lot of things that we
could go to with that one.
I'll try to avoid that
if at all possible.
I don't know why
you would want to pump.
But why do we want
to pump protons?
Here is why
we want to pump protons.
Who is this guy?
You know this guy too.
That£s ATP synthase and ADP + P
is turning into--
I£m going to put my ATP up here
just for the heck of it.
Do you feel like, dude,
I knew all that?
It£s easy, isn't it, once you
know cellular respiration.
There are a couple of
questions that you should
probably be asking here.
We need an electron acceptor
don£t we?
So be thinking about that.
Who is going to
accept these electrons?
I want you to know
that we actually gave up
electrons here.
These electrons got passed down.
We need to find someone
to accept them
but we also are going to need to
replace those electrons
in photosystem II and I want you
to think about that.
I£m going to come back and we£re
going to look at photosystem I.
