1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein...

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1 Nucleic acids Nucleic acids Nucleic acids Nucleic acids: Maintain genetic information Maintain genetic information Determine Protein Synthesis Determine Protein Synthesis DNA DNA = deoxy deoxyribonucleic acid Master Copy” for most cell information. Template for RNA RNA = RNA = ribonucleic acid Transfers information from DNA Template for Proteins
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Transcript of 1 Nucleic acids Nucleic acids Nucleic acids: –Maintain genetic information –Determine Protein...

  • Slide 1
  • 1 Nucleic acids Nucleic acids Nucleic acids: Maintain genetic information Determine Protein Synthesis DNAdeoxy DNA= deoxyribonucleic acid Master Copy for most cell information. Template for RNA RNA = RNA = ribonucleic acid Transfers information from DNA Template for Proteins
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  • 2 Nucleic Acids Chromosomes (in nucleus) genes Have genes 1 gene 1 enzyme or protein Enzymes determine external & internal characteristics
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  • 3 NUCLEIC ACIDS nucleotides. Long chains (polymers) of repeating nucleotides. 3 parts: Each nucleotide has 3 parts: A phosphate unit sugar A sugar heterocyclic A heterocyclic Amine Base
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  • 4 Nucleotide = phosphate + sugar + base -N-glycosidic linkage -N-glycosidic linkage Base Sugar Phosphate Nucleoside = sugar + base
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  • 5 Nucleic Acids Nucleic AcidspolymersNucleotides. Nucleic Acids = polymers of Nucleotides. phosphate sugar base SSSSSS BB B BBB PPPPPP
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  • 6 THE SUGAR PART The major difference between RNA and DNA is the different form of sugar used. O HOCH 2 H H H H OH OH O HOCH 2 H H H H OH H Ribose C 5 H 10 O 5 in RNA Deoxy DeoxyRibose C 5 H 10 O 4 in DNA carbon #2 The difference is at carbon #2.
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  • 7 The Nitrogenous Bases 5 basestwo classes 5 bases used fall in two classes Purines & Pyrimidines double ring A double ring (6 & 5 members) single ring A single ring (6 membered)
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  • 8 Pyrimidines: The Nitrogenous Bases Purines: Adenine (A) Guanine (G) Thiamine (T) In DNA only Thiamine (T) In DNA only Uracil (U) In RNA only Uracil (U) In RNA only Cytosine (C)
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  • 9 Nucleotides Di- & Tri- Phosphates Adenosine 5-monophosphate (AMP) Adenosine 5-monophosphate (AMP) ribose Adenine
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  • 10 Adenosine 5-monophosphate (AMP) Adenosine 5-monophosphate (AMP) ribose Adenine Adenosine 5-diphosphate (ADP) Nucleotides Di- & Tri- Phosphates
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  • 11 Adenosine 5-monophosphate (AMP) Adenosine 5-monophosphate (AMP) ribose Adenine Adenosine 5-diphosphate (ADP) Adenosine 5-triphosphate (ATP) Nucleotides Di- & Tri- Phosphates
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  • 12 Primary structure
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  • 13 Primary structure Phosphate bonds link DNA or RNA nucleotides together in a linear sequence. Similar to proteins with their peptide bonds and side groups. 5 3 Adenine (A) Guanine (G) Thymine (T)
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  • 14 Structure of DNA
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  • 15 In 1938 William Thomas Astbury took the first fiber diffraction pictures of DNA, correctly predicting, in an article in the journal Nature, the overall dimensions of the molecule and that the nucleotide bases were stacked at intervals of 3.3 perpendicular to its long axis. It was left, however, to Watson and Crick after the Second World War to elucidate the detailed double helical structure of DNA.
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  • 16 Maurice Wilkins with one of the cameras he developed specially for X-ray diffraction studies
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  • 17 Work on x-ray diffraction patterns by Maurice Wilkins and Rosalind Franklin in 1953, revealed that the molecule had a "helical shape.
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  • 18 Rosalind Franklin is most associated with the discovery of the structure of DNA. At 26, after she had her PhD, Franklin began working in x-ray diffraction - using x-rays to create images of crystallized solids. She pioneered the use of this method in analyzing complex, unorganized matter such as large biological molecules, and not just single crystals. Franklin made marked advances in x-ray diffraction techniques with DNA. She adjusted her equipment to produce an extremely fine beam of x-rays. She extracted finer DNA fibers than ever before and arranged them in parallel bundles. And she studied the fibers' reactions to humid conditions. All of these allowed her to discover crucial keys to DNA's structure. Maurice Wilkins, her laboratory's second-in-command, shared her data, without her knowledge, with James Watson and Francis Crick, at Cambridge University, and they pulled ahead in the race, ultimately publishing the proposed structure of DNA in March, 1953. It is clear that without an unauthorized peek at Franklin's unpublished data, Watson and Crick probably would neither have published their famous paper on the structure of DNA in 1953, nor won their Nobel Prizes in 1962. Franklin did not share the Nobel Prize; she died in 1958 at the age of 37.
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  • 19 1953, James Watson & Francis Crick and their scale model for DNA
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  • 20 DNA secondary and tertiary structure Sugar-phosphate backbone coil outside of the attached bases Causes each DNA chain to coil around the outside of the attached bases like a spiral stair case. Base Pairing purines and pyrimidines Hydrogen bonding occurs between purines and pyrimidines. This causes two DNA strands to bond together. adenine - thymine guanine - cytosine Always pair together! Results in a double helix structure.
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  • 21 Base pairing and hydrogen bonding N N O | - H N - H N N N N O | H - N N N O | O | H3CH3C - H guaninecytosine thymineadenine N N N N|N| H H N
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  • 22 Complementary Base Pairing Position of H bonds and distance match with: DNA - Secondary Structure
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  • 23 Hydrogen bonding Each base wants to form either two or three hydrogen bonds. Thats why only certain bases will form pairs. G T C A C G A C T G
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  • 24 Sugar- phosphate backbone coils outside of attached bases DNA coils around outside of attached bases like a spiral stair case. Results in a double helix structure.
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  • 25 The double helix The combination of the stairstep sugar- phosphate backbone and the bonding between pairs results in a double helix. The combination of the stairstep sugar- phosphate backbone and the bonding between pairs results in a double helix. Distance between bases = 0.34 nm 2 nm between strands One complete twist is 3.4 nm
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  • 26 DNA - Secondary Structure Complementary Base Pairing
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  • 27 The actual chain is like a coiled spring. It is something similar to what happens when protein chains form an alpha helix. It is the sequence (order) of the amines coming off of the backbone that give us all our genetic information Just like the sequence of words in a sentence give it meaning. Of the like in words meaning just sentence a give sequence it. (Get my meaning ? )
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  • 28 Crick and Watson (1962 Nobel Prize) Proposed the basic structure of DNA 2 strands wrap around each other Strands are connected by H- bonds between the amines. Like steps of a spiral staircase
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  • 29 Chromosomes Chromosomes consists of DNA strands coiled around protein - histomes. The acidic DNAs are attracted to the basic histones.
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  • 30 It also was clear in the 1960s that the chromosomes of cells
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  • 31 Chromosomes The normal number of chromosome pairs varies among the species. Animal PairsPlantPairs Man 23Onion 8 Cat 30Rice 14 Mouse 20Rye 7 Rabbit 22Tomato 12 Honeybee,White pine 12 male 8Adders 1262 female16tongue fern
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  • 32 Role of RNA and DNA in Heredity RNA and DNA are involved in three major processes in a cell related to heredity as shown below: 1.Replication (DNA copies itself) 2.Transcription (The genetic code in DNA is rewritten into RNA and carried to the ribosomes by mRNA 3.Translation (tRNA carries amino acids to the ribosomes as part of protein synthesis Replication is an important process during mitosis Transcription and translation are two steps in the biosynthesis of a protein
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  • 33 DNA: Self - Replication aid of enzymesWhen a cell nucleus divides, the bridging hydrogen bonds break (with the aid of enzymes) and the intertwined strands unwind from each other. amines left sticking free to pick up new partnersThe amines left sticking out from each strand are now free to pick up new partners from the plentiful supply present in the cell.
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  • 34 P S P S P S P S ATGC PS T PS G Each A picks up a T, each C picks up a G, etc... Eventually, every amine group is reunited with its complimentary amine and the lost partner strand is reformed. They now twine around each other to form the new Double helix.
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  • 35 T C A SSSSSSGTCAPPPPPP CG G DNA: Self - Replication
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  • 36 G G A SSSSSSGTCAPPPPPP CG DNA: Self - Replication T C C
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  • 37 Replication of DNA Replicationboth halves Replication occurs on both halves opposite directions. in opposite directions.
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  • 38 DNA Replication
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  • 39 RNA synthesis In the first step, RNA polymerase RNA polymerase binds promotor to a promotor sequence on the DNA chain. insures correct direction This insures that transcription occurs in the correct direction. The initial reaction is to separate the two DNA strands DNA strands.
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  • 40 RNA synthesis initiation sequence termination sequence Special base Special base sequences sequences in the DNA indicate RNA where RNA synthesis starts and stops.
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  • 41 RNA synthesis Once the termination sequence is reached, the new RNA molecule and the RNA synthase released. are released. The DNA recoils.
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  • 42 messenger RNA to the cytoplasm RibosomesThe messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival. rRNA
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  • 43 messenger RNA to the cytoplasm RibosomesThe messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival. rRNA
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  • 44 messenger RNA to the cytoplasm RibosomesThe messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival. rRNA
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  • 45 messenger RNA to the cytoplasm RibosomesThe messenger RNA (mRNA) move outside the nucleus to the cytoplasm where Ribosomes are anxiously awaiting their arrival. rRNA
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  • 46 rRNA Ribosomal RNA rRNA Ribosomal RNA rRNA: Platform for protein synthesis. Holds mRNA in place and helps assemble proteins.
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  • 47 AUG GCU AUG UUG 5 3 rRNA Ribosomes like train stationsThe Ribosomes are like train stations mRNA is the train The mRNA is the train slowly moving through the station. rRNA Codons mRNA
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  • 48 Transfer RNA - tRNA Transfer RNA - tRNA = small 70-90 bases.) relatively small compared to other RNAs (70-90 bases.) transports amino acids transports amino acids to site of protein synthesis.
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  • 49 Anticodons on t-RNA Site of amino acid attachment Site of amino acid attachment Three base anticodon site Three base anticodon site Point of attachment to mRNA Point of attachment to mRNA
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  • 50 UUU or UUC is the codon for Phe. UUG is the codon for Leu. AUG is the codon for Met.
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  • 51 Codons There are two additional types of codons: Initiation AUG (same as methionine) TerminationUAG, UAA, UGA A total of 64 condons are used for all amino acids and for starting and stopping. All protein synthesis starts with methionine. After the poly- peptide has been made, an enzyme removes this amino acid.
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  • 52 Protein Synthesis 1: Activation Each AA is activated by reacting with an ATP tRNA The activated AA is then attached to particular tRNA... (with the correct anticodon) C G A MET anticodon activated AA
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  • 53 Translation AUG GCU AUG UUG mRNA 5 3 Initiation factors ribosome unit U A C MET P site A site
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  • 54 U A C MET Translation ribosome unit AUG GCU AUG UUG mRNA 5 3 P site A site C G A Ala
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  • 55 ribosome unit AUG GCU AUG UUG mRNA 5 3 Translation U A C MET C G A Ala peptide bond forms
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  • 56 ribosome unit GCU UUC UUG mRNA 5 3 Translation C G A Ala peptide bond Met A A G Phe A U G U A CU A C
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  • 57 ribosome unit GCU UUC UUG mRNA 5 3 Translation C G A Ala peptide bond forms Met A A G Phe A U G U A C
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  • 58 Termination After the last translocation (the last codon is a STOP ), no more AA are added. Releasing factors cleave the last AA from the tRNA The polypeptide is complete
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  • 59 Recombinant DNA Circular DNA found in bacteria E.Coli plasmid bodies Restriction endonucleases cleave DNA at specific genes Result is a sticky end Addition of a gene from a second organism Spliced DNA is replaced and organism synthesizes the new protein
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  • 60 Recombinant DNA Bacterium Remove gene segment DNA Plasmid sticky ends Cut gene for insulin Replace in bacterium
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  • 61 http://www.learner.org/resources/series61.html