Ribosomes Video Lecture | Science for ACT

welcome to this tutorial today where we
are going to be talking about ribosomes
a very complex and amazing machine that
we have within our cells so let's just
write down that we have a eukaryotic
cell for demonstration purposes and a
mitochondria but don't let this fool you
you'll have ribosomes within your
prokaryotic cells as well and there are
also many varieties of ribosomes but in
this tutorial we will just discuss the
basic form and function and before we
start talking about the ribosomes I just
want you to know that we have a
structure or area within our nucleus
called the nucleoli and that is going to
be where we synthesize these subunits of
our ribosomes and we're not going to be
talking about the nucleoli within this
video so we'll just leave it at that and
know your ribosomes are synthesized here
now the actual ribosome itself is a non
membranous 2 subunit our protein complex
so non membranous it doesn't have its
own membrane and we don't classify it as
an organelle within the cell and I'm
just drawing lots and lots of ribosomes
all over the cell here so they're
absolutely everywhere some of them just
floating around wherever they want and
some attached to membranes so they're
not organelles and I'll draw some within
the mitochondria here as well because I
wanted to distinguish that as well
because within our mitochondria we have
a different type of ribosome and our
mitochondria can make those itself okay
so we have our ribosomes all through the
cell and the mitochondria but we are
going to learn very much from the little
dots all over the screen so let's zoom
in to a individual ribosome here and we
can see that large and small sub you
so we'll write that down small and large
subunits and we'll point that out here
quickly on the diagram as well so we
have this large subunit here and we have
these small subunit at the bottom and
they are both going to have completely
different roles and we haven't really
actually talked about that role yet
apart from where I wrote down a two
subunit protein factory but what does
protein factory mean and I'll just write
there that it's a globular protein as
well so a small subunit it's going to
have a role in reading RNA now RNA being
the a strand of genetic material that's
going to carry the code for the proteins
that we need to make in our cell during
translation and the RNA is going to be
composed of a long chain of nucleotides
now the large subunit of the ribosome
complex is going to be joining amino
acids to a growing polypeptide chain and
it does this by having access points for
T RNAs and these T RNAs or transfer RNAs
are going to be carrying amino acids and
they will come along to the access
points within the large subunit of your
ribosome and each tRNA will recognize a
different code that the RNA strand
associated with your small ribosomal
subunit is presenting and if it's
carrying an amino acid that corresponds
to that code it will attach it to a
growing polypeptide chain and we can see
that chain extending out into a protein
and that's the process we call
translation and this is what we call the
ribosomes the protein factories of our
cell and the ribosome itself apart from
the small and large subunit is also
going to contain some of its own RNA
which we call our RNA or ribosomal our
and the whole structure itself the RNA
the smaller large subunits we refer to
as the translational apparatus so if you
hear the term translational apparatus
just think oh I know that that's just a
ribosome okay we know the structure of
our ribosomes now and we know the
purpose of it what it's doing but the
last thing I want you to know is they're
not all in the same spot and you can see
I've just drawn this weird-looking
squiggly line or tube you'll type system
up here which is called our rough
endoplasmic reticulum and the reason
I've drawn that is because some of our
ribosomes are membrane bound and the
reason we call our rough endoplasmic
reticulum rough is because it's studded
with ribosomes all over it and other
ribosomes are going to just be freely
floating around our cell so you can see
them up here and down just a bit lower
I've got ribosomes kind of floating all
over the place so the location that
they're at will determine what type of
proteins they're going to be making
whether they are in the membrane of your
mitochondrion or on the rough
endoplasmic reticulum or just floating
around in the cytoplasm now we know all
of the basics about our ribosomes what
they're doing and where we're going to
find them within the cell I hope this
video has been helpful to you as always
thanks for watching and I'll see you
again soon