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U5(c2): tRNA Codon/amino- acid "Redunancy" & "Junk" – Part II. Mr. Gibson Biochemistry I Class Lecture Hall - 213/Laboratory -214 Week of April 16, 2012. The "Redundancy " & "Junk" for Codons. Notice the amino acid. Leucine (L)?. The "Redundancy " & "Junk" for Codons. - PowerPoint PPT Presentation
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Mr. Gibson Biochemistry I Class
Lecture Hall - 213/Laboratory -214
Week of April 16, 2012
The "Redundancy " & "Junk" for
Codons
Notice the amino
acid. Leucine (L)?
The "Redundancy " & "Junk" for
CodonsLeu uses the (not only)
one set of codons within
one of our 16 code boxes
that have the same 1st
two letters, (but also)
another box of codons
with another pair of
different 1st two letters –
although they are the
same within the that
box, they are different
when compared to the
other box.
The "Redundancy " & "Junk" for
Codons
Recent lab analysis
has shown there are
purposes for both
[the] “redundancy”
& “junk”.
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
Regarding [the]
“redundancy”….
Let’s say the cell calls for the
amino acid shown here –
alanine; to be inserted at
multiple points on the
polypeptide (multiple amino-
acids) chain in a particular
protein …
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
Regarding [the]
“redundancy”….
The 1st two letters
(nitrogenous bases) guanine
& cytosine – will deliver a
tRNA molecule with the
amino acid alanine
covalently bonded to its
acceptor arm.
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
Regarding [the] “junk”….
The 3rd letter (nitrogenous
base) of the codon makes no
difference in terms of
delivering the correct tRNA
molecule with the alanine
amino acid covalently
bonded to its acceptor arm.
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
Although the cell
needs (proteins) to
(operate) and
(maintain) itself;
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
The cell does not want
proteins to be… too many or
too few for its needed
processes
OR
to hang around for too long
or too short of a time as it
is being used.
GCUGCCGCAGCG
A
The "Redundancy " & "Junk" for
Codons
At a level of study that would be
too complex and take up too much
time for our understanding -- we
can say this:
Muliple codons with different 3rd
letters… do tell the proteins that
come out of the ribosome
translation process how long they
are to hang out in a cell once
delivered…
The "Redundancy " & "Junk" for
Codons
AND;
also tells the proteins how
many or few of them are to
show up at the cell (correct
amounts) to meet the cell’s
needs.
The "Redundancy " & "Junk" for
Codons
In fact…
If there are too many or too few
proteins –or-
if they don’t break down
(denature) and go away thus hang
around for too short or long of a
time;
a third type of disease occurs in all
living cells.
The "Redundancy " & "Junk" for
Codons
As you may recall from your
biology class studies; there
are two types of diseases that
destroy cells (a) bacteria
and (b) viruses.
The "Redundancy " & "Junk" for
Codons
A third type of disease prion
disease all centers around the
tRNA bringing the correct
amino acid along with its
correct directions in terms of
amount (expression) & longevity
(dwell time)for the ribosome to
make the protein possessing the
correct structure/information-
function [as] dictated by the
“redundant” & “junk” codons/3rd
letter.
The "Redundancy " & "Junk" for
Codons
Prion diseases are always
debilitating and often fatal.
Many, many times it doesn’t
even show up in a living
organism until much later in
its life cycle – and then, with
devastating results.
The "Redundancy " & "Junk" for
Codons
A vivisection (cross-section) of
a human brain with areas that
are degenerating (breaking
down… getting soft or mushy);
A cow that is loosing the
motor function in its legs due
to nerve degradation
(breaking down, no longer
able to carry electrical
impulses).
The "Redundancy " & "Junk" for
Codons
We now have a glimpse into
understanding the nature,
importance and complicated
directions that are delivered by the
codons as they relate to amino acids
and protein amounts/life
expectancy;
We will next look at the make up of
the “manufacturing site” – the
ribosome – in terms of its parts &
functions of those parts.
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