Structural support Metabolism Motion Defense DNA replication RNA synthesis etc And many more functions Overview of Protein Synthesis The information in DNA is used to make proteins In order to get from DNA to protein an intermediary mRNA is necessary ID: 1009897
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1. ProteinsProteins are used for a variety of functions in the cell:Structural supportMetabolismMotionDefenseDNA replication, RNA synthesis, etc.And many more functions
2. Overview of Protein SynthesisThe information in DNA is used to make proteinsIn order to get from DNA to protein, an intermediary, mRNA, is necessaryThe information in the mRNA is translated into the amino acids chains that make up the protein by molecules of tRNA
3. Protein SynthesisEvery cell in your body has the same DNAThe DNA in the cell has the instructions for making the proteins that the cell needsDifferent cells need different proteins, and not all proteins are needed all the timeNot every protein is made in every cellGenes are regulated so that the necessary proteins are made
4. 7/31/2016Dr. S. ABBASI4What is the codon1- Synthesis of artificial RNA molecules 1955 Severo Ochoa discovery of Polynucleotide Phosphorylase no need DNA template for RNA synthesis2- Cell free Protein Synthesis with a Homopolymers & a random HeteropolymersDr. Marshall Nirenberg & Heinrich Mattahaei from National Institute of Health Laboratories in 1961 , 26 of May on Friday in 6 Am could synthesis a Poly phenylalanine from poly (U) (Homopolymer).5`-UUU-3`=Phenylalanine codon5`-AAA-3`=Lysine codon5`-CCC-3`=Proline codon5`-GGG-3`=Glysine codon
5. The Genetic Code (1)Information based on a Triplet codeCodons are the basic unitGroups of 3-nucleotides 64 (43) possible codons61 specify one of the 20 amino acidsthree are stop codonsThe ordering and grouping of the nucleotides is called the reading frameThis could be proof by: 1-Counting # of nucleotide on mRNA and compare with # of amino acids on same protein 2-Single mutation (deletion or addition)1961 crick & Brenner on (T4) rIIb bacteriophage Acridine dyes such as Proflavin
6. Codons…letters in the sentence
7. Codon Table
8. 7/31/2016Dr. S. ABBASI8The Genetic Code (2,3)The code is Degenerate , more than one codon for an Amino Acids-All aa Except Methionie (AUG) & Triptophane (UGG) have more than one codon-Ala , Val, Gly, Pro, Thr with 4 codons-Ilu with 3 codons-Ser, Lue, Arg with 6 codons-Others with 2 codonsThe code has Direction ; 5`→ 3` -mRNA 5`UUGGUU 3` is Lusine & Valine not Valine & Lusine-mRNA 5`-AAAUUU-3`is Lysine & Phenylalanine
9. 7/31/2016Dr. S. ABBASI9The Genetic Code (4)WOBBLE Hypothesis 1966 by Dr. CrickIn Anticodon the third base is less important -Inosine in third position of Yeast anticodon CGI (Anticodon tRNA of Alanien) can pairs with any of these codons GCU, GCC,GCA, GCG (with all :A,U,C,G )When 2 amino acids common in first 2 digits the third in one is purin and in another is pyrimidine;-His CAU & CAC (pyrimidine) and Glu CAG & CAA (Purine)-with exception of those , with 6 codons :Arg, ser, Leu
10. 7/31/2016Dr. S. ABBASI10The Genetic Code (5,6,7)The code contains Punctuation codons (termination codons):UAA (Ochre)UAG (Amber)UGA (Opal)(AUG is initiation codon for Methionine)There is No Space between codesThe codes are Not Overlap
11. 7/31/2016Dr. S. ABBASI11The Genetic Code (8)The genetic code is Not Universal-up to1979 thought it is universal because:Rabbit ribosomes +Rabbit mRNA + E.Coli tRNAs →→active Rabbit Hemoglobin-in 1979 Sanger and his group in Cambridge U . worked on Mitochondrial Translation : There are differences in Nuclear codes and Mitochondrial codes
12. 7/31/2016Dr. S. ABBASI12Examples of non-standard codes Organism Genes codon Universal meaning Actual meaning1- Mammals all Mitochondria UGA Termination Trp AGA,AGG Arg Termination AUA Ile Met2-Yeast `` UGA Termination Trp CUN Lue Thr AUA Ile Met3-Protozoa all nuclear UAA,UAG Termination Glu4- Human `` UGA Termination Selenocysteine ↓ ( in Glutathione Peroxidase & Iodothyonine5`-deiodinase)