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BELLRINGER!!

BELLRINGER!!. Describe One differences between DNA & RNA. Recall from reading. Please Pass up your GREEN Parent signature sheet!. DNA V.S. RNA. OBJECTIVES. Compare DNA to RNA Structures Protein Synthesis Three types are RNA. How do we get from D N A to Proteins ?.

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BELLRINGER!!

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  1. BELLRINGER!! Describe One differences between DNA & RNA. Recall from reading Please Pass up your GREEN Parent signature sheet!

  2. DNA V.S. RNA

  3. OBJECTIVES • Compare DNA to RNA • Structures • Protein Synthesis • Three types are RNA

  4. How do we get from DNA to Proteins?

  5. From nucleus to cytoplasm… • Where are the genes? • genes are on chromosomes in nucleus • Where are proteins synthesized? • proteins made in cytoplasm by ribosomes • How does the information get from nucleus to cytoplasm? • RNA nucleus

  6. Why would RNA be useful in a cell?

  7. DNA is the MASTER PLAN RNA is the copy of the master plan

  8. Since DNA can’t leave the nucleus, we need something to carry the message to the ribosomes RNA 8

  9. RNA is similar to DNA EXCEPT: DNA RNA Structure DOUBLE strand SINGLE strand Sugar DEOXYRIBOSE RIBOSE Base A C G T URACIL (not thymine) 9

  10. Structure of RNA 10

  11. Pair the RNA BASES! • G=C • C=G • T=A • A=U

  12. Three Types of RNA Messenger RNA (mRNA) Ribosomal RNA (rRNA) Transfer RNA (tRNA) . 12

  13. Messenger RNA mRNA- Copies DNA’s code & carries the genetic information to the ribosomes Single, straight strand of nucleotides 13

  14. Ribosomal RNA rRNA-binds to the mRNA and assemble the amino acids in the correct order 2 subunits: Large small 14

  15. Transfer RNA tRNA- transfers amino acids to the ribosomes where proteins are synthesized Clover-leafshape One end carries the amino acid; Opposite end has three nucleotide bases called the anticodon 15

  16. 16

  17. Transcription

  18. Objectives • Describe the three step process • Initiation • Elongation • Termination

  19. DNA Transcription Ribosome mRNA Translation Polypeptide (protein) IntroductionThe Central Dogma of Molecular Biology Cell

  20. Protein Synthesis • Flow of Information: • DNA RNA Proteins • Transcription Translation • Transcription is the process by which a molecule of DNA is copied into a complementary Strand strand of RNA.

  21. Protein Synthesis DNA cytoplasm DNA nucleus Transcription RNA RNA Translation (mRNA) carries the code (tRNA) brings in amino acids Proteins (rRNA) makes a ribosome Amino acid chain folds into a functional protein

  22. http://www.youtube.com/watch?v=ztPkv7wc3yU&feature=related

  23. Transcription • Transcription: the synthesis of mRNA from a DNA template • mRNA, rRNA, and tRNA must all be transcribed for protein synthesis to take place

  24. Transcription - Initation STEP 1: DNA strands separate • RNA POLYMERASE (RP) recognizes a promoter on the DNA sequence • PROMOTER: base sequence that signals the start of a gene • DNA is split by RP and one strand is used as a template • **Only ONE strand will be transcribed RNA Polymerase

  25. - brings in complimentary RNA nucleotide to base pair with DNA C G U U A U G G C RNA Elongation: RNA Polymerase RNA Polymerase **Same process as replication EXCEPT only 1 strand is copied, and U replaces T

  26. Remember the Complementary Bases On DNA: A-T C-G On RNA: A-U C-G

  27. Question: What would be the complementary RNA strand for the following DNA sequence? DNA 5’-GATACGTATG-3’

  28. Answer: • DNA 5’-GATACGTATG-3’ • RNA 3’-CUAUGCAUAC-5’

  29. Termination: the process continues until RNA polymerase reachesatermination signalin the DNA which indicates the end of a gene

  30. Translation

  31. Objections • Describe the three steps in Translation • Translate mRNA codons into amino acids

  32. Translation makes Proteins from RNA

  33. Translation • http://www.youtube.com/watch?v=-zb6r1MMTkc&feature=related

  34. Reading the DNA code • Every 3 DNA bases pairs with 3 mRNA bases • Every group of 3 mRNA bases encodes a single amino acid • Codon- coding triplet of mRNA bases

  35. Virtually all organisms share the same genetic code “unity of life” Second Base U C A G UUU UCU UAU UGU U tyr phe cys UUC UCC UAC UGC C ser U UUA UCA UAA stop UGA stop A leu UUG UCG UAG stop UGG trp G CUU CCU CAU CGU U his CUC CCC CAC CGC C pro arg leu C CUA CCA CAA CGA A gln CUG CCG CAG CGG G First Base Third Base AUU ACU AAU AGU U ser asn AUC ACC AAC AGC C ile thr A AUA ACA A AAA AGA lys arg AGG AUG ACG AAG G met (start) GUU GCU GAU GGU U asp GUC GCC GAC GGC C val G ala gly GUA GCA GAA GGA A glu GUG GCG GAG GGG G

  36. Initiation • mRNA bindswith the ribosome’s small subunit. • A “start” codon (AUG) on mRNA signals the beginning of a protein chain.

  37. Happens at Ribosomes • Ribosomes read mRNA three bases (1 codon) at a time and construct the proteins • Have two sites for tRNA attachment --- P and A 38

  38. Amino acid Polypeptide Asite P site Anticodon mRNA 1 Codon recognition mRNAmovement Stopcodon Newpeptidebond 2 Peptide bond formation 3 Translocation Figure 10.14

  39. Elongation mRNA is on a ribosome with the start codon AUG A tRNA with anticodon UAC can now bind to mRNA because bases match up. Peptide bonds join the amino acids Ribosome moves over one codon – opens P-site The process repeats until…….

  40. Elongation • The mRNA moves a codon at a time relative to the ribosome • A tRNA pairs with each codon, adding an amino acid to the growing polypeptide • A STOP codon causes the mRNA-ribosome complex to fall apart

  41. Ribosomes build polypeptides Next amino acidto be added topolypeptide Growingpolypeptide tRNA molecules P site A site Growingpolypeptide Largesubunit tRNA P A mRNA mRNAbindingsite Codons mRNA Smallsubunit Figure 10.12A-C

  42. tRNA Function • Amino acids must be in the correct order for the protein to function correctly • tRNA lines up amino acids using mRNA code

  43. Translation in action! Translating the message into Protein Click image to view movie

  44. Step 3: Termination Occurs when a stop codon is reached The string of amino acids (polypeptide) is released Subunits break apart. 46

  45. End Product –The Protein! The end products of protein synthesis is a primary structure of a protein A sequence of amino acid bonded together by peptide bonds aa5 aa4 aa3 aa2 aa199 Met aa200 47

  46. 48

  47. For ALL life! strongest support for a common origin for all life • An amino acid may have more than one codon,but each codon makes only ONE amino acid • There is also: • 1 start codon (AUG = methionine) • and • 2 stop codons. 49

  48. Codons and Anticodons The 3 bases of an anticodon are complementary to the 3 bases of a codon MET-tRNA codon codon anticodon mRNA codon

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