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.