HAZEL SIVE: After your
exercise in translation,
you should be able to look
at genetic code tables
and go from the messenger RNA
to the corresponding amino acid.
You should understand
the concept
of a codon and an anticodon.
And you should be able
to take a piece of RNA
and translate it
conceptually into protein.
You should also know the
direction of protein synthesis
that we discussed
before, but it should now
be very clear in your mind.
So what we've done
today is to take DNA.
We've discussed
how it is precisely
replicated using the rules
of nucleic acid 3 prime end
addition, complementarity,
antiparallelism.
We've talked about
how DNA is turned
into RNA by transcription.
And we've talked
about how RNA is then
turned into the completely
different language of protein.
We care about this deeply
because the proteins
and sometimes the RNAs are
final products of genes.
They are what makes
the cell work.
They are what makes the
organs of the body work.
They are what makes
you and me work.
So the final products
are essential for life
or very useful for life.
That is why we care about this
whole information transfer.
Let's end off today's discussion
by going through one more
example from gene to protein.
Let's start off with a piece
of double-stranded DNA 5
prime ATGGAAGCT.
Just checking my notes here.
The complementary strand you
now know-- do it with me--
TACCTTCGA 5 prime.
If we make this bottom
strand the template strand,
but as you know, I could
have made the top strand
the template strand.
It's just a matter
of convenience
that I've done it this way.
The RNA that comes out
will be the complement
of this template DNA strand.
It will be AUG/GAA/GCU.
There's a little trick
here I want to tell you.
The sequence of
the RNA is actually
the same as the nontemplate
strand sequence.
And if you ever need
that on a problem
set or some other reason,
you should remember that.
So the RNA looks like
the nontemplate strand,
except that there
are Us instead of Ts.
And now we can take this RNA.
And we can divide
it into codons.
And we can translate
it AUG/GAA/GCU.
And the protein that will
come out of this translation--
methionine lysine threonine.
And these are covalently
joined together
the direction of the
strand of protein
from amino to carboxy end.
This is what you should
know by this point.
And you should know
the various rules
by which these different
aspects of information
transfer in biology work.
So to summarize what
we've talked about today,
we've talked about the
gene and DNA rules.
We've talked about DNA
replication and transcription.
And then we culminated
this all with a discussion
of translation.
You're well on your way
now to understanding
some of the basics in
biology and to start
to understand how
you can figure out
which gene does what and, when
genes are abnormal or mutated,
what the outcomes
are going to be.
And we'll talk about that
kind of thing next time.
