Looking for a Tutor Near You?

Post Learning Requirement »
x

Choose Country Code

x

Direction

x

Ask a Question

x

x
x
For better view click here
x
Hire a Tutor
DISCOVER

Gene Code

Loading...

Published in: Biology
17,524 Views

Gene Coding is described here.

R. K / Chennai

7 years of teaching experience

Qualification: Pursuing M.Sc.(Botany)

Teaches: Bio Technology, Biology, Botany, EVS, School Level Computer, Zoology, Social Studies, NET

Contact this Tutor
  1. THE GENETIC CODE CYTOSINE U RACIL GUANINE
  2. HISTORY Francis Crick • James Watson and structure(1953) o Information in the DNA strand>>Protein? • Marshall Warren Nirenberg, Har Gobind Khorana Willlom +10114/0 (Nobel prize in physiology or medicine )
  3. o Genetic information-Nucleus of cell o Linear sequence of Nucleotides-Single strands of DNA helix. o Protein synthesis 1st step-dsDNA>>ssRNA, where 2nd tRNA-read Genetic code in mRNA>>Protein What is C GenetiC cod CoClon- triplet nucleotide sequence + Codon For a 3 letter code made from the 4 nucleotide bases there are 64 different possible arrangements or code letters (codons).
  4. mRNA tRNÅ. p rote in cc c cc c pro pro coding strand cr-ldon antic.üdon c
  5. Francis Crick-Nobel lecture Summary o Most of the Codons consist of 3 adjacent bases Adjacent codons do not overlap The message is read in the correct groups of three by starting at some fixed point * The code sequence in the gene is co-linear with the amino acid sequence, the polypeptide chain being synthesized sequentially from the amino Degeneracy Ambiguity The Code in different organisms maybe similar
  6. Breaking Of genetic code required a cell-free protein-synthesizing system Prepairing a cell•free symhesizing systen Src•w• b:cteriä in culture and Éclate by centrifugation. 'l Grind cells to release cellular contents, ireudiræ RNA ONA ribosomes, enzymes. and ath:r corr portents reed2d far trarslatian. Deoxyribonuclease Add dearyTibonuclease. This enzyme destroys all the cellular CIAA, and ra more mRNA is prcduced. Protein synthesis stops mRNA of known sequence Labeled amino acids Restart translation by idiirv; m oi known sequence labeled eminc acids to the tube, incubate the solution at 37>C. The protein produced by system can be precipitäted by äding trichlorc- acetic acid. (15.8 Breaking the genetic code required a cell-free protein-synthesizing system.
  7. Cracking the code - A Clever Experiment Marshall W. Nirenberg free system + all the things needed for protein synthesis. Strands of template were run with all combinations of nucleotides in the cell free system. Made a very simple N.a composed of only chains of 1 single repeated nucleotide protein containing only
  8. Question: What ami no acids are specified by codons composed of only one type of base? UUUUUUUUUUUUUUUUUU Polynucleotide phosphorylase Uracil nucleotides A homopdyner this czse. pclyfl„l) mRNA} was Added ta a test tube contv-ing cell-free translation system. 1 racia- actively libeled smino acid. and 10' unl±eled &Tiino acids. The protein was filtered and the filter was checked for radioeti'Wty. Suction homopolymer The tube arc. Trsrslätian tcak gaze. Precipitate protein Free amino acids The WES repeate:i in 20 'tubes, with tube containing different 'abeced amino wd. Pro ILys Arg Phe Asp Clu His Trp Ser Ala Thr Val Asn Ile Cin Leu Cys Met The tube in which the protein was labele:i cantained newly synthesized protein with the arrirn acid specified by the hcnopolymar. In this casa, LILILI specified amino acid phenylälanine. Conclusion: ULILI codes for phenylal•nine; in other experiments, AAA was found to code for alanine, and CCC for praline. 159 Nirenberg and Matthaei developed a method for identifying the amino acid specified by
  9. Synthetic mRNA (one codon) & Ribosome bound tRNA Experiment Question: With the use oftRNAs, what other matches between codan and amino acid could be determined? Very st-art rr 'Mth krmvn ccdons 'were svlthuzed... GOU Synthetic -mRNA with one codon GCA CAC tRNAs with amino acids Mix Ribosome ard added to a mixture of ribosomes ard tRNLs attsched to •ninc Aids. The ribosome bound the RNA and the tRNAs that it *ecified. Unbou nd tRNAs Ribosome with mRNA and tRNA specified codon Filter solution mixture was then pzssed through nitrocellulose filter. The tRNAs psired with ribcsame-bound m RNA stuck to filter, whereas unbound tRNAs passed through. The 'RN.Ös on the filter were bound to valine. Conclusion: The codan GIJU specifies valine; many other 'dons were determined by using this method. (15.11 Nirenberg and Leder developed a technique 'for using ribosome-bound tRNAs to provide additional information about the genetic code.
  10. Solving the rest of the puzzle + Har Gobind Khorana using biochemical methods, produced long strands of RNA with every nucleotide in exact position. The first one he made was a strand repeating the two nucleotides . This translated into a strand of amino acids, reading nucleic acid called transfer RNA or tRNA for short. In 1965 Holley was worked out its exact structure. tRNA turned out to be the missing molecule that Crjdk had proposed in his 'ASAClÉJÅter JElypOlh1e31Sjj ten years earlier.
  11. Features Of the Dictionary start codon O Read in 5'-3' direction. stop codons* o The code is Triplet, Unpunctuated EfiÉl Nonoverlapping Degenerate/Redundant The code is The Genetic Code is The exceptions so far are AUG, UGA and IJAG. The code is orr rr The Genetic Code is + Initiation codon sets the reading frame in which the message is Translated.* o Wcjbble Concept -(1966,Francis crick) Base at I$encl of the aritjd0C10fj -forms hydrogen bonds
  12. Visualizing the Code c G tRNA A anticodon U codon 2nd base mRNA 3' in co don Phe Leu Leu Met Val Val Ser Ser Ser Ser Pro Thr STOP STOP His His Gin Gin Lys Glu Glu cys STOP Arg Arg Arg Arg Arg Arg The Genetic Code
  13. overlapping cede AGACGAUUAUCAACAGCC AGACGAU AGACGAU comma-free cde AGACGAUUAUCAACAGCC OGACGAU ßGACGAlJ U A U CAAC AG UAUCAACAGC UAUCAACAG UAUCAACAGC c Overlapping code packs 16 codons into 18 base-pairs by exploiting triplets in all three phases, or reading frames. A comma-free code is constructed so that only the codons in one reading frame are meaningful; the overlap triplets are nonsense (black).
  14. Frozen accident or evolved and evolvable? Translation system of the bacterium E coli produces functioning proteins from human genes: humans and E coli apparently shared the same coding rules . Inspite of the evolutionary distance the same code is universal that the rules can never change no matter how long the time scale under consideration. Francis crick- 'Frozen accident'. Yeast ,humans and several other species- mitochondria,UGA - tryptophan. Yeast mitochondria ,CUA-threonine instead of leucine. Mammalian mitochondria, AUA-methionine instead of isleucine.
  15. Wobble pairing The wobble rules. indicating which bases 'in the third position (3' end) of the mRNA codon cm pü with bases at the first (5' end) of the anticodon of the tRNA Anticodon ACC Codon A, U, orc Päiring st the third ccdcn position is rel:xed. C can pair '"sith C.. V.bb±le position . cr '"ith U. Table 15.2 First Position of Anticodon c 1 {Inos[ne) Third Position of codon UorC ( 15.13 Wobble may exist in the pairing of a codon on mRNA with an anticodon on tRNA. The mRNA and tRNA pair In an antiparallel fashion. Pairing at the first and second codan positions [s Iin accord with the Watson and Crick pairing rules (A with T, G with O; however, pairing rules are relaxed at the third position of the codom and C on 'the anticadan can pair with either u ar c on the codon In -this example. Pairing Antlcodon codon Antlcodon 3 c cadan Antlcodon cadan Antlcodon codan Antlcodon c codan
  16. + Marshall Nirenberg the genetic code in 1961. + Har Gobind Khorana creator produce synthetic nucleic acids. + Robert Holley , the discoverer of the transfer RNA - tRNA.
  17. Exception Of Genetic code Some exceptions to the universal genetic code universal Altered Genome codon code Bacterial DNA Mycoplasma caprfcofum UGA Mitochondrial DNA Human Human Human Yeast ornanosames Plants Nuclear DNA Tetrahpnena Paramecium UGA ALIA ACA, AGG UGA UGA CCC UAA UAC stap stop Ile Arg stap stap Arg stap stap code Met stop cin cin
  18. MUTATIONS Changing a single base will change the codon, usually into one for another amino acid ? sickle cell anemia GAG = GUG Glutamic acid Ellije - makes the hemoglobin sticky - ppts out of the soln. Types: 3. Missense Mutation* Nonsense/stop Mutation* Frameshift Mutation*
  19. Using the Code Today o Production of selected proteins o Production of pharmaceuticals.-The DNA that encodes the protein you want is synthesized and put in bacteria. A new copy of the desired protein is produced every time the bacterium divides . E coli bacteria -useful proteins, for example lirj3Ljljn (to treat diabetic patients) and different coÉjclLllÉj1jon factors that are needed by patients suffering from hemophilia.

Need a Tutor or Coaching Class?

Post an enquiry and get instant responses from qualified and experienced tutors.

Post Requirement

Related PPTs

Upload PPTs

If you have your own PowerPoint Presentations which you think can benefit others, please upload on LearnPick. For each approved PPT you will get 100 Credit Points and 100 Activity Score which will increase your profile visibility.

Upload Now
Home > PowerPoint Slides > Gene Code