The next important structure
in our cells is the ribosomes.
And the ribosomes are important because
this is where we synthesize all of our proteins.
So the process of translation
occurs at the ribosomes.
The ribosomes is actually made
up of two subunits of ribosomal RNA
with some proteins also mixed in together.
And together those two
units thread through mRNA
on one side and out on the
other side, you get proteins.
So switching gears, the endoplasmic reticulum is first
of several organelles that we will discuss today.
The endoplasmic reticulum is going
to be located just off of the nucleus
and extend into the cytoplasm of the cell.
There are two different types
of endoplasmic reticulum.
The rough endoplasmic reticulum
also known as the rough ER
and the smooth endoplasmic
reticulum also known as the smooth ER.
These two both have very different functions where the
rough endoplasmic reticulum is gonna be responsible
for modifying proteins that are
being translated on their surface.
whereas the smooth ER is responsible for the production
of different lipids as well as steroid hormones.
The smooth ER is also
important for detoxification
which is why liver cells have
an extensive network of Smooth ER.
Extending from the ER, the next major organelle is
going to be the golgi complex or the golgi apparatus.
the golgi apparatus is actually directional where
the part of the Golgi that is closest to the nucleus
is referred to as the cis-golgi and the part that is further
away from the nucleus is referred to as the trans-golgi.
Transport vesicles containing proteins leaving the
ER are transported to the cis side of the golgi
where they are further processed in the cell.
I like to think of the golgi as
kind of like a 'FedEx' in our cell
and the reason why is beacuse a lot of
sorting and packaging occurs in this organelle.
Specifically things come in, they are
modified or tagged with a certain zip code
and then told where to go next.
If something is destined
to be secreted from the cell,
it will always go through the golgi first and then
from there, be taken to the plasma membrane.
And they can also be taken to other
parts of the cell and other organelles as well.
So all these together, give us
our endomembrane system.
The endomembrance system starts with
the nucleus which we will discuss shortly,
and after that goes to the ER followed by
the golgi and then to the plasma membrane.
And so something that is synthesized at the
ER can eventually be secreted out of the cell
through this transport system involving
these membrane-bound organelles
and the transport vesicles between them.
So other organelles that are part of the
endomembrane system but are not necessarily
in that pathway toward the outside
of the cell, are things like lysosomes.
So lysosomes are derived from the golgi
apparatus but these contain digestive enzymes
and it's is actually very
similar to our stomach.
And what this does is it breaks
down large particles and molecules
into smaller things that
can then be used by the cell.
So in a way, the lysosome is
like the stomach of our cells.