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DNA

DNA. DNA. CLIP. 1. DNA. located in the nucleus Function: Carry genetic material Many People contributed to the discovery of DNA. 2. People Who Discovered DNA. 1928 – Frederick Griffith - DNA = carrier of genetic info 1944 – Avery – Genes = composed of DNA

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DNA

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  1. DNA DNA CLIP 1

  2. DNA • located in the nucleus • Function: Carry genetic material • Many People contributed to the discovery of DNA. 2

  3. People Who Discovered DNA • 1928 – Frederick Griffith - DNA = carrier of genetic info • 1944 – Avery – Genes = composed of DNA • 1952 – Hershey and Chase – genetic material = DNA, not protein 3

  4. People Who Discovered DNA • 1952 – Rosalind Franklin – DNA = twisted • 1952 – Edwin Chargraff - #A = #T; #C = #G; Chargraff’s Rule • 1953 – Watson and Crick – Discovered structure of DNA we know today 4

  5. What we Know Now........ 5

  6. Shape of DNA • Double Helix. -Twisted ladder or spiral staircase • Two stranded • Held together by hydrogen bonds • Made of four Nucleotides 6

  7. Structure of DNA Remember: • DNA is a nucleic acid. • Nucleic acids are made of nucleotides 7

  8. DNA = long chain of nucleotides 4 that make up DNA Have 3 parts: a sugar molecule (deoxyribose), a phosphate group, and a nitrogenous base Nucleotides 8

  9. Adenine Guanine Cytosine Thymine 4 NitrogenousBases 9

  10. Sides of the “Ladder” are made up of sugar and phosphate. 10

  11. Adeninealways pairs with ThymineCytosinealways pairs with Guanine 11

  12. Would Thymine be able to pair up with Guanine? NO!! 12

  13. 13

  14. DNA REPLICATION DNA Replication 20 14

  15. DNA Replication • Before mitosis, the DNA must be replicated (Copied) exactly. • Each strand can be used to make the other strand. • Many enzymes are involved. 15

  16. Chromosome Structure • DNA is packed very tightly as chromosomes in the nucleus. • Human nucleus has 1 meter of DNA! • Smallest human chromosome has 30 million base pairs. 16

  17. Chromosome Structure • A chromosome has DNA and protein-chromatin. • Tiny sections of DNA are called genes 17

  18. Semi-conservative replication Steps: • parent/original strands are unwound with the help of DNA helicases (enzymes). Replication Bubble 18

  19. Replpication Bubbles 19

  20. Steps: 2.DNA polymerase attached new nucleotides to the parent strands 20

  21. DNA replication website 21

  22. How a protein is made • Transcription • Translation 22

  23. DNA codes for all of the cell proteins. 23

  24. DNA Transcription 24

  25. Overview: DNA is located in the Nucleus Proteins are made on the ribosomes. DNA makes a copy (send a message) called “mRNA” 25

  26. 1. Transcription 2. Translation Two Steps of Protein Synthesis 26

  27. Transcription • a copy of the DNA is made…the copy is called messenger RNA or mRNA. • The mRNA takes the code to the ribosome. 27

  28. DNA vs. RNA • Single Stranded • AGUC • Ribose • YES! • Double Stranded • AGTC • Deoxyribose • NEVER! 28

  29. DNA Transcription • During transcription the DNA unzipped and RNA nucleotide are paired up with the DNA bases. • Website 29

  30. DNA Translation 30

  31. 31

  32. Once the mRNA copy is made, it can go to the ribosome to be translated. 32

  33. Remember….Proteins are made out of amino acids. There are 20 different amino acids. 3 bases code for each amino acid = codon. 33

  34. How you figure out which codon is coding for which amino acid… 34

  35. Once the mRNA gets to the ribosome, the protein can be assembled. Transfer RNA brings the amino acids to the ribosome. Website 35

  36. The three letter code on the mRNA is called a codon. • The three letter code on the tRNA that is matched up with the mRNA is called an anticodon. 36

  37. Review Clip 37

  38. Mutations 38

  39. Mutations • A sudden change in the genetic code is called a mutation. • Most mutations have little or no effect on the organism. • Mutations can be spontaneous or may be caused by environmental factors called mutagens. 39

  40. Mutations in DNA usually occur through one of two processes: 1- DNA damage from environmental agents such as ultraviolet light (sunshine), nuclear radiation or certain chemicals. 2- Errors that occur when a cell replicates its DNA in preparation for cell division. 40

  41. Types of Mutations 41

  42. Point mutation -a simple change in a single base of the gene sequence • 3 Types: • Point • Insertion • Deletion 42

  43. Original: THE CAT ATE THE RAT Deletion: THE CAT ATE THE RAT THE CTA TET HER AT Insertion THE CAT ATE THE RAT THE CAT ATT ETH ERA T Frame-shift Mutations In a frame-shift mutation, one or more bases are deleted or inserted, the equivalent of adding or removing letters in a sentence. 43

  44. DNA MutationsHarmful, Helpful, Neutral • Substitutions • Frameshift • Deletions • Insertions • Causes: • Mutagens • UV light • Radiation • Chemicals (ex: substances in tobacco products) • Replication errors CLIP 51 44

  45. 53 45

  46. Which of the following is the correct base-pairing rule for DNA? AA-U; C-G BA-G; T-C CA-T; G-C DA-C; T-G 46

  47. DNA TECHNOLOGY industry DNAfingerprinting agriculture medicine genetic recombination. forensics 47

  48. DNA Fingerprinting How they identify criminals and do paternity tests (i.e. “Who is my Baby’s Daddy?”) 48

  49. How DNA Fingerprinting works: • Scientist cut up DNA into pieces using enzymes • Then load the pieces into a gel. • Electricity is run through the gel. • The pieces of DNA move to the other end of the gel. • Smaller pieces move farther. 49

  50. Who doesn’t belong? 50

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