Hello everyone. My name is Dr. Douglas Houston,
I'm a lecturer at Edinburgh University.
Today, I'm going to be talking about "The Biochemistry of DNA and RNA".
Part 1 looked at the chemistry of these molecules and for this Part 2,
we are going to be looking at their expression and biological function.
So that's fundamental chemistry of DNA structure and also protein DNA interaction.
So let's zoom out a little and see exactly how DNA works at,
I guess, a more biological level.
So here, we can see a schematic or flowchart which I'm guessing will probably have being
seen somewhere before because this often gets called the
central dogma of biology or biochemistry.
So this is the idea,
that we have a strand of DNA,
so this is the green line at the top.
This contains all of the information that is
needed to produce a protein from any particular gene.
That's called expression and that expression happened via transcription and translation,
which I'm sure you've encountered before.
So how exactly does a stretch of nucleotide bases in DNA,
how is it actually able to end up as
a very specific sequence of amino acids in a protein?
So as I said, it goes via a process of transcription and
that transcription relies on a molecule called RNA which is very closely related to DNA,
almost identical but not quite.
RNA is quite a complex molecule,
tends to be more complex than people give it credit for.
This is hinted at in this slide where we can see first of all
the different subtypes of RNA and also
the differences in RNA between eukaryotes and prokaryotes.
So similarities between eukaryotes and prokaryotes being they both use messenger RNA,
mRNA and this is arguably
the most important one or at least the best understood form of RNA.
They both use transfer RNA,
this again is a very important component of protein expression.
They both use ribosomal RNA,
again important in expression.
But then eukaryotes have this whole collection of miscellaneous types of RNA.
We have heterogeneous nuclear RNA,
small nuclear RNA, and small cytoplasmic RNA.
These do lots of different jobs that I'm not going to go into in this lecture.
Because I'm interested in the expression of DNA,
I'm going to be talking about mRNA, tRNA, and rRNA.