Hello and welcome to our lecture on structure and function.
Here we'll be exploring cell organelles.
Now that we have a great understanding of
how macromolecules are built,
let's put them together a bit and
explore how organelles come together to make the cell.
By the end of this lecture, you should have
a great understanding of the nucleus and the nuclear pores
as well as the endomembrane system which is involved
in transport of materials from the cell.
In addition to that, you'll have an understanding of how eukaryotic
cells perhaps became so much more complex than prokaryotic cells.
So as we move forward, let's begin by looking at one question,
how big is a mitochondria?
Going back to the question of scale that we look at earlier
in the course, mitochondria are quite small.
In fact, they are small enough that we can barely see them
inside the cell looking in a light microscope.
If we look at our larger cell, the human egg cell,
we could see that fairly clearly under a microscope
and we may be able to see the mitochondria inside that cell.
So moving forward that gives us just a little bit of scale,
so that we can review again how much larger an eukaryotic cell is
than a prokaryotic cell. It's about ten times larger.
Because it's ten times larger,
it needs to have a little bit more complexity
and localization of functions in different organelles
so that the right materials are in the right place
to accomplish the right task at the right time.
So, we'll notice that there's a lot of compartmentalization.
The nucleus, for example, contains all of the linear chromosomes.
And we have many organelles inside the cell such as
our mitochondria, the power house of the cell.
In this lecture, we're going to explore the roles
of each of these different organelles.
So as for compartmentalization,
we have two distinct regions to think of
or two distinct reasons that compartmentalization
is possible inside the cell.
First of all, this endomembrane system,
it all arises from the phospholipid bilayer membranes.
And phospholipid bilayer membranes seemed to be
folded in from the external membrane
or perhaps even arose from internal membranes
because these internal membranes often produce the phospholipids
for the external cell membrane. So the endomembrane system
is one division that we'll explore.
And then there are other membrane bound organelles inside the cell.
We will specifically be paying attention to mitochondria
because we're focusing on animal cells
However, plant cells also have membrane bound organelles
in the form of chloroplasts.
In addition to these complex compartments,
the eukaryotic cell needs a little bit more structure.
So it has a cytoskeleton. Much like our own skeleton,
the cytoskeleton gives the cell structure and support,
in addition to allowing the cell to transport materials throughout.
Imagine a neuron, we have a cell body up here by the spine
and it needs to make its way all the way down to the tips of our toes.
How do we get materials from the cell body up here
all the way down to the tips of our toes?
Well we have to have some mechanisms of transport.
So as we move forward, we'll begin to take a look into how
this cytoskeleton helps in this transport mechanism.