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DNA: The Molecule of Life

DNA: The Molecule of Life. Alan D. Morales Biology. Introduction. Genetic code : the program of the cell that is passed from one generation to another; tells cells what to do and how to do it Must be able to: 1. duplicate itself quickly and accurately 2. be decoded and put into effect .

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DNA: The Molecule of Life

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  1. DNA: The Molecule of Life Alan D. Morales Biology

  2. Introduction • Genetic code: the program of the cell that is passed from one generation to another; tells cells what to do and how to do it • Must be able to: • 1. duplicate itself quickly and accurately • 2. be decoded and put into effect

  3. Discovery of DNA • Griffith: 1928--discovered transformation of bacteria • Avery: 1944-discovered that DNA was the transforming factor • Hershey and Chase: 1952-studied whether viruses that infect bacteria inject protein or DNA • PA Levine- Discovered the nitrogenous bases, deoxyribose, and phosphate group. • Franklin and Wilkins: DNA has a helical structure

  4. What is DNA? • Deoxyribose Nucleic Acid • Chargraff • A=T, G=C • James Watson and Francis Crick • Model of DNA • Double stranded structure • Bases inside

  5. DNA-Deoxyribose Nucleic Acid

  6. What is DNA Made of? • 5-carbon sugar (Deoxyribose) • Phosphate • Nitrogenous Base • Adenine (A) • Guanine (G) • Thymine (T) • Cytosine (C)

  7. What are the Structures of the bases? • Purines • Adenine • Guanine

  8. What are the structures of the bases? • Pyrimidines • Thymine • Cytosine

  9. A View of base pairing • A:T • 2 hydrogen bonds

  10. A View of Base Pairing • G:C • 3 hydrogen bonds

  11. What is important about base pairs? • Can predict sequence of one strand based on the sequence of the other. • Replication and Transcription • Repair of damaged DNA

  12. Linking it all together: A, G, C or T Forms sugar Phosphate Backbone What makes DNA Different from RNA?

  13. Where is DNA in the cell? • Prokaryotic cell: Cytoplasm • Eukaryotic cell: in the chromosomes

  14. DNA-Chromosome Formation • http://www.cleanvideosearch.com/media/action/yt/watch?videoId=4PKjF7OumYo

  15. DNA Replication: • Why? • When cells divides, each new cell needs it’s own copy of DNA. • Where? • Nucleus in Eukaryotes. • Cytosol in Prokaryotes • When? • S phase of Interphase • What causes? • DNA Polymerase

  16. DNA Replication

  17. DNA Replication • DNA Helicase cause DNA to unwind and unzip • SSB: Single strand binding protein keeps DNA separated • RNA Primase add a short segment on each end • DNA Polymerase causes addition of new nucleotides • 3’ to 5’ direction • Leading and Lagging strand • Matching on Base pairing

  18. DNA Replication • Okazaki fragment is small segment of lagging strand of DNA formed during replication • DNA Ligase connect the Okazaki fragments

  19. Comparing DNA Replication in Eukaryotes and Prokaryotes cells • Eukaryotes cells unwind in multiple areas • Prokaryotes cells unwind only in area of replication

  20. DNA Replication Lab • DNA Replication Video

  21. RNA Transcription

  22. Transcription • DNA RNA • What is the difference between DNA and RNA? • Sugar: Ribose • Strands: 1 • Instead of thymine • =Uracil • A, U, C, G

  23. Types of RNA • mRNA-messenger RNA • Take message from DNA out of nucleus to ribosomes • tRNA-transfer RNA • Transfer code to protein • rRNA-ribosomal RNA • Assist with making protein

  24. Transcription • Where? • Nucleus in Eukaryotes • Cytosol in Prokaryotes • What? • DNA copied/written by mRNA • When? • When protein is needed

  25. Transcription • How? • RNA polymerase • Base-pairing • A-U and G-C • Only one strand • RNA Synthesis Animation

  26. Transcription

  27. Transcription Lab

  28. Translation • Language of RNA instructions • A, U, G, C • Codon: three consecutive nucleotides that forms a specific single amino acid from mRNA. • 1 codon=3 nucleotides • Anticodon-3 consecutive nucleotides that from tRNA

  29. Codon • tRNA Molecule Example: UCGCACGGU • UCG-CAC-GGU • Serine-Histidine-Glycine • UCG=Serine • CAC=Histidine • GGU=Glycine • Start Codon • AUG • Stop Codon • UAA, UAG, UGA

  30. Amino Acids-Proteins • Amino acids are attached to tRNA • Amino acids joined together into long chains to make proteins • Protein properties are determined by order of amino acid. • 20 different amino acids

  31. The Genetic Code

  32. Translation • What? • mRNA with tRNA & rRNA Protein • Where? • Cytosol • When? • When proteins are needed • Why? • Proteins are vital for cells

  33. Translation • How? • Ribosomal Subunits • mRNA, tRNA, & rRNA • Stages of Translation • Initiation: AUG starts process • Elongation: Amino acids attach to each other • Termination: ends with stop codon • Translation Animation

  34. Quick Lab • What is the difference between DNA and RNA? • Replicate the following DNA Molecule: (hint: in DNA Replication you will match it to another DNA molecule): GACAAGTCCACAATC • Transcribe the following DNA Molecule (hint: in Transcription you will match it to mRNA molecule): GACAAGTCCACAATC

  35. Genetic Code

  36. Quick Lab Answers • What is the difference between DNA and RNA? • Sugar: Ribose • Strands: 1 • Instead of thymine • Replication of DNA Molecule: CTGTTCAGGTGTTAG • Transcribe into mRNA molecule: CUGUUCAGGUGUUAG

  37. Protein Synthesis Review • Replicate the following DNA molecule • DNA: GACTTACCGGGA • DNA: CTGAATGGCCCT • Transcribe the following DNA molecule • DNA: GACTTACCGGGA • mRNA: CUGAAUGGCCCU

  38. Protein Synthesis Review • Translate the following RNA molecule into a protein • mRNA: CUGAAUGGCCCU • tRNA: GACUUACCGGGA • GAC-UUA-CCG-GGA • Aspartic Acid-Leucine-Proline-Glycine

  39. Pop Quiz • Translate following mRNA molecule: GACAAGUCCACAAUC • tRNA strand: • Amino Acid:

  40. Pop Quiz Answers • Translate from mRNA molecule to amino acid sequence via tRNA • tRNA strand: CUG-UUC-AGG-UGU-UAG • Amino Acid: Leucine-Phenylalanine-Arginine-Cysteine-Stop

  41. Genes and Protein • Genes contain information to assembly Protein • Proteins carry out the instructions of the genes • One gene-One enzyme • Beadle-Tatum

  42. Gene Regulation • Ability of an organism to control which genes are transcribed in response to the environment

  43. Gene Regulation • Prokaryote Cells • Operon-Segment of DNA that contains genes for the protein in specific metabolic pathway • Eukaryote Cells • Regulate protein synthesis using various transcription factors, nucleosomes structures and RNA interferences

  44. Why is this important? • Mutations • Genetic Engineering • Gene Splicing • Cloning

  45. Mutations • Mutation-change in the DNA sequence that affect genetic information • Types of Mutations • Point Mutation • Chromosomal Mutation

  46. Mutations • Point Mutation- • one nucleotide has changed

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