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DNA D eoxyribonucleic A cid

DNA D eoxyribonucleic A cid. Nature vs. Nurture?. DNA. We know traits are inherited but how are they inherited?. Chargaff ’ s Rule. Chargaff ’ s Rule. X-ray Evidence. 1952 Rosalind Franklin took an x-ray diffraction to take picture of DNA shape Picture gave clues to structure of DNA.

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DNA D eoxyribonucleic A cid

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  1. DNADeoxyribonucleic Acid

  2. Nature vs. Nurture?

  3. DNA We know traits are inherited but how are they inherited?

  4. Chargaff’s Rule

  5. Chargaff’s Rule

  6. X-ray Evidence • 1952 Rosalind Franklin took an x-ray diffraction to take picture of DNA shape • Picture gave clues to structure of DNA

  7. Watson & Crick • Watson & Crick made a model of DNA structure • Won Nobel Prize

  8. Watson and Crick’s model of DNA was a double helix

  9. The Components & Structure of DNA Nucleotide 1. 5-carbon sugar deoxyribose 2. phosphate group 3. nitrogenous base i. Adenine ii. Thymine iii. Guanine iv. Cytosine

  10. Nucleotides are monomers! • Nucleotides are linked in a strand • The sides of the “ladder” are phosphates and the sugar deoxyribose

  11. Sugar & phosphate form backbone- The bases form the “steps” of ladder, held together by Hydrogen bonds • C-G = 3 hydrogen bonds • A-T = 2 hydrogen bonds

  12. How is DNA Packaged? • DNA is wrapped around proteins • called histones forming beads • These beads pack together, forming • nucleosomes. • These coil to make chromatin • When the chromatin (stringy DNA) coils it make a chromosome

  13. DNA Replication • Think about DNA’s structure • Perfect for use of replication! • Each original side is a Template

  14. Parent Strand Or Template Daughter strand

  15. Before a cell divides, it duplicates its DNA in a process called replication. • This makes sure each cell will have a complete set of DNA

  16. How is it done?! 1. DNA is unwound 2.DNA helicase enzyme unzips the weak hydrogen bonds between base pairs 3.DNA polymerase enzyme matches up nucleotides to complement the other side 4. Strands checked for error

  17. “Semi-conservative”- why?

  18. Replicate your own DNA • 1. Take piece of paper and fold is vertically • NOW REPLICATE Label • Template/ Parent Strand • Hydrogen Bonds • Complementary Base Pairing • DNA Helicase • DNA Polymerase • Daughter Strands

  19. Central Dogma • DNA  RNA Protein • DNA gives the instructions for RNA which gives the instructions to make proteins

  20. Central Dogma

  21. What is a gene? • Part of the DNA (letters/bases) that code for a particular protein

  22. Genotype vs. Phenotype • Genotype, genetic makeup, is the sequence of bases in the DNA • Phenotype,traits, due to proteins

  23. Proteins we learned! Structural • Keratin ( hair, skin and nails ) • Muscles Reactions • Enzymes(lactase) Signal • Insulin, human growth hormone Hemoglobin- carriers oxygen in your red blood cells

  24. RNA vs DNA • RNA • Ribonucleic Acid • Ribose Sugar • A,C,G,U • U = Uracil • Single Stranded

  25. Transcription RNA copies the message from DNA - Called messenger RNA ( mRNA) Complementary base pair ( NO T!! In RNA) Only copies a gene of the DNA mRNA Leaves the Nucleus

  26. Transcription • Enzyme that build RNA strand • RNA polymerase

  27. RNA Splicing Introns stay in the nucleus Exons join (splice) together and exit – final mRNA

  28. Translation mRNA to Protein 1. mRNA goes to the Ribosome • Each 3 letters of the mRNA is called a codon 2. Each mRNA codon bonds to a tRNA (transfer RNA) anticodon • Complementary Base paring rules 3. tRNA carries the amino acid which builds the polypeptide (protein) 4. Begins with mRNA start codon AUG and ends with mRNA STOP Codon

  29. Introduction Worksheet • http://learn.genetics.utah.edu/content/begin/dna/transcribe/ • Transcribe and Translate a Gene

  30. SHOW REAL TIME • Great Simple Video!!

  31. Mutations http://www.dnalc.org/resources/3d/17-sickle-cell.html

  32. 1 base change in 438-base sequence. Change in DNA, change in RNA, change in Amino Acid Hemoglobin protein does not work properly to carry oxygen.

  33. Tay Sachs Cracking the Code:17:00-20:00 Inherited genetic mutation • Mutation in a gene that codes for an enzyme protein that breaks down fatty acids in the brain

  34. Mutation • Change in the nucleotide Sequence ( letters/bases) of a gene • Base Substitution (can be bad or silent) 2. Base Addition/ Deletion- worse - Frameshiftmutation= alter group of 3 Affects the function of the PROTEIN

  35. ADDITION • THE CAT ATE THE RAT • THE ACA TAT ETH ERA T

  36. Mutagens cause Mutations • Xray, UV light, smoking chemicals, pesticides • Sometimes GOOD? How so?

  37. Example of Inherited DNA Mutations: Diseases

  38. Mutations

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