U5(c2): tRNA Codon/amino- acid "Redunancy" & "Junk" – Part II

1. U5(c2): tRNACodon/amino- acid "Redunancy" & "Junk" – Part II Mr. Gibson Biochemistry I Class Lecture Hall - 213/Laboratory -214 Week of April 16, 2012

2. The "Redundancy " & "Junk" for Codons Notice the amino acid. Leucine (L)?

3. The "Redundancy " & "Junk" for Codons Leu 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.

4. The "Redundancy " & "Junk" for Codons Recent lab analysis has shown there are purposes for both [the] “redundancy” & “junk”. A GCU GCC GCA GCG

5. The "Redundancy " & "Junk" for Codons GCU GCC GCA GCG A 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 …

6. 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. A GCU GCC GCA GCG

7. The "Redundancy " & "Junk" for Codons Regarding [the] “junk”…. The 3rd letter (nitrogenous base) of the codon makes no differencein terms of delivering the correct tRNA molecule with the alanine amino acid covalently bonded to its acceptor arm. A GCU GCC GCA GCG

8. The "Redundancy " & "Junk" for Codons Although the cell needs (proteins) to (operate) and (maintain) itself; A GCU GCC GCA GCG

9. The "Redundancy " & "Junk" for Codons The cell does notwant 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. A GCU GCC GCA GCG

10. 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 longthey are to hang out in a cell once delivered…

11. The "Redundancy " & "Junk" for Codons AND; also tells the proteins how many or fewof them are to show up at the cell (correct amounts) to meet the cell’s needs.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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).

17. 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.