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DNA

DNA. LAB: Extract your DNA. DNA? Where is it located? What is the shape? What has DNA?. DNA knowledge!. Deoxyribonucleic Acid. Nucleus. Double Helix. Living Organisms. 20th century – Major challenge: What arethe molecules of inheritance?

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DNA

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  1. DNA LAB: Extract your DNA

  2. DNA? Where is it located? What is the shape? What has DNA? DNA knowledge! Deoxyribonucleic Acid Nucleus Double Helix Living Organisms

  3. 20th century – Major challenge: What arethe molecules of inheritance? • T. H. Morgan’s group showed that genes are located on chromosomes • The 2 components of chromosomes—DNA and protein—became candidates for the genetic material • 1928 - Frederick Griffith discovered of the genetic role of DNA by working with two strains of a bacterium, one pathogenic and one harmless. Discovering dNAis the genetic material

  4. nitrogen-containing base phosphate group deoxyribose (sugar) It was known that DNA is a polymer of nucleotides, each consisting of a nitrogenous base, a sugar, and a phosphate group In 1950, Erwin Chargaff reported that DNA composition varies from one species to the next Additional Evidence That DNA Is the Genetic Material

  5. New Challenge: What is the structure of DNA? • Maurice Wilkins and Rosalind Franklin (King’s College)were using a technique called X-ray crystallography to study structure • Franklin produced a pictureof the DNA molecule using this technique (photo 51) Finding the Structure of DNA

  6. The Discovery of DNA Structure • 1953 – Watson and Crick (Cambridge University) saw Photo 51 and discovered the structure of DNA. • Double Helix – long twisted zipper Segment with James Watson

  7. The double helix of a chromosome is so thin that it only be detected through innovative, high-tech procedures. Chromosomal DNA from a single cell is not visible to the naked eye. However, when chromosomal DNA is extracted from multiple cells, the DNA can be seen. We will collect cheek cells. Then, we will lyse the cell membranes by adding a detergent. (This allows the DNA to be freed.) DNA is soluble in water, but much less soluble in alcohol. Thus, alcohol will be slowly added, and DNA will precipitate to the sports drink/alcohol interface, and you will be able to see your own DNA! Lab!!

  8. Read Molecular structure of Nucleic Acids Discovering the Structure of Dna

  9. nitrogen-containing base phosphate group deoxyribose (sugar) • DNA is made of nucleotides of • Deoxyribose (sugar) • PO4 (phosphate group) • Nitrogen bases • 1. adenine—A • 2. guanine—G • 3. thymine—T • 4. cytosine—C BUILDING BLOCK/MONOMER

  10. A or G T or C • Double ring PURINES Adenine (A) Guanine (G) • Single ring PYRIMIDINES Thymine (T) Cytosine (C) Nitrogenous Bases

  11. hydrogen bond covalent bond A bonds to T with 2 hydrogen bonds G bonds to C with 3 hydrogen bonds BASE PAIRING Rules

  12. DNA makes a copy of DNA • Where? In the nucleus • Semiconservative Replication • Parental strands separate and serve as templates • New DNA have one parent strand and one new strand Replication

  13. Step 1 – DNA helicase breaks the H+ bonds between the nitrogen bases (un-zipping DNA) Step 2 – Free floating nucleotides in the cell bond to the complementary bases on the original strands Step 3 – An enzyme secures the two strands together, forming two new chains DNA replication animation Steps to replication

  14. Replication occurs in 3’ to 5’ direction. • DNA polymerase adds the nucleotides • Two strands: • Leading Strand • Lagging Strand – • Okazaki fragments • DNA replication animation

  15. CGATATATTCCCGAG ATTCAGTTCAGACCC ACGTTATACGCTAAC Practice!!

  16. Central dogma Central Dogma DNA RNA PROTEIN

  17. DNA RNA Where? In the nucleus animation Transcription

  18. 1. RNA has a sugar ribose DNA has a sugar deoxyribose 2. RNA contains the base uracil (U) DNA has thymine (T) 3. RNA molecule is single-stranded DNA is double-stranded RNA Differs from DNA

  19. CGATATATTCCCGAG ATTCAGTTCAGACCC ACGTTATACGCTAAC For you to try…TRANSCRIPTION

  20. Messenger RNA (mRNA) - carries genetic information Ribosomal RNA (rRNA) - makes the ribosomes Transfer RNA (tRNA) - transfers amino acids to the ribosomes where proteins are made . Three Types of RNA

  21. start codon A U G G G C U C C A U C G G C G C A U A A mRNA codon 1 codon 2 codon 3 codon 4 codon 5 codon 6 codon 7 Messenger RNA (MRNA) mRNA has a code (codon) for tRNA

  22. RNA protein Where? In cytoplasm. The chain of amino acids linked together is a specific protein. animation Translation

  23. GCUAUAUAAGGGCUC UAAGUCAAGUCUGGG UGCAAUAUGCGAUUG For you to try… TRANSLATIONMAKE AMINO ACIDS

  24. amino acid attachment site Phenylalanine amino acid A A G anticodon Transfer RNA (tRNA)

  25. GCUAUAUAAGGGCUC UAAGUCAAGUCUGGG UGCAAUAUGCGAUUG For you to try… MAKE ANTICODONS

  26. Given the following DNA sequence • CGATATATTCCCGAG • 1. What is the complimentary DNA? • 2. What is the mRNA strand (codon)? • 3. What amino acids are created? • 4. What is the tRNA (anticodon)? For you to try

  27. MUTATION-error • Substitutions • Insertions • Deletions • Frameshift • Translocation • Inversion • Not all are harmful • Read Happy Birthday Double Helix What if there is a mistake?

  28. SUBSTITUTION

  29. CCA TAT CAT GGC CCA TAT GCA TGG C INSERTION

  30. DELETION

  31. Original: • The fat cat ate the wee rat. • Frame Shift (“a” added): • The fat caatet hew eer at. FrameshiftMutationS HAPPEN BECAUSE OF INSERTIONS OR DELETIONS

  32. CCC GCG ATT TAT CCC TAT ATT GCG TRANSLOCATION

  33. INVERSION

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