DNA PDF

• DNA


  Located inside the nucleus, tightly coiled molecule that contains genes, building blocks of nucleic acids together with RNA, key features: stored, replicated, expressed and diversified

  
• DNA


  Deoxyribonucleic Acid, contains genetic instructions, made up of 2 strands, A-T, C-G base pairing, located in the nucleus, blueprint of biological guidelines

  
• RNA


  Ribonucleic Acid, one of the three macromolecules essential to life, made up of 1 strand, A-U, C-G pairing, located in the cytoplasm, assists in carrying out DNA's blueprint guidelines

  
• Central Dogma of Molecular Genetics

  DNA → RNA → Protein

  
• Early scientists thought protein was the cell's hereditary material because it was more complex than DNA</b>
• Proteins were composed of 20 different amino acids in long polypeptide chains
• Transformation


  • Fred Griffith found that R strain Pneumoccocus bacteria could become virulent when it took in DNA from heat-killed S strain, suggesting DNA was probably the genetic material
• Hershey & Chase experiment

  • Proved that DNA was the cell's genetic material

  
• Chargaff's Rule


  Adenine must pair with Thymine, Guanine must pair with Cytosine, the bases form weak hydrogen bonds

  
• DNA Structure


  • Rosalind Franklin took diffraction x-ray photographs of DNA crystals, Watson & Crick built the first model of DNA using Franklin's x-rays
• DNA Double Helix


  Most DNA has a right-hand twist with 10 base pairs in a complete turn, left twisted DNA is called Z-DNA or southpaw DNA, hot spots occur where right and left twisted DNA meet producing mutations
• DNA Nucleotide


  Made up of phosphate group, 5-carbon sugar, and nitrogenous base

  
• Pentose Sugar


  Carbons are numbered clockwise 1' to 5'
• Antiparallel Strands


  One strand of DNA goes from 5' to 3', the other strand goes from 3' to 5'

  
• Nitrogenous Bases


  Double ring purines (Adenine, Guanine), single ring pyrimidines (Thymine, Cytosine)

  
• If there is 30% Adenine, there would be 20% Cytosine
• Genetic Code


  Allows DNA and RNA sequences to be "decoded" into the amino acids of a protein