Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Notes ch12 DNA

349 views

Published on

  • Be the first to comment

  • Be the first to like this

Notes ch12 DNA

  1. 1. Chapter 12: DNA
  2. 2. ∗ DNA has 3 functions: ∗ Storing information ∗ Copying information ∗ Transmitting information 12.1 The Role of DNA
  3. 3. ∗ DNA – deoxyribonucleic acid ∗ Nucleotides – monomers that make up a DNA molecule ∗ 3 parts: ∗ 5 Carbon sugar (deoxyribose) ∗ Phosphate group ∗ Nitrogenous base ∗ Adenine (A) ∗ Guanine (G) ∗ Cytosine (C) ∗ Thymine (T) 12.2 The Structure of DNA
  4. 4. ∗Edwin Chargaff (1949) ∗Chargaff’s Rule ∗[A]=[T] ∗[C]=[G] Solving the Structure of DNA Adenine Thymine Guanine Cytosine 35% 45%
  5. 5. ∗ Rosiland Franklin used X-ray diffraction to visualize DNA structure (1952).
  6. 6. ∗ Watson and Crick were the first to model DNA as a double helix in 1953.
  7. 7. ∗ All the previous discoveries show us the structure of DNA and how DNA can function as a carrier of genetic information. ∗ Characteristics of the double helix model: ∗ Antiparallel strands ∗ Hydrogen Bonding ∗ Base Pairing The Double Helix Model
  8. 8. Antiparallel Strands ∗Run in opposite directions Base Pairing ∗Bases are held together by hydrogen bonds. Base Pairing ∗A bonds with T, and C bonds with G ∗ Complimentary base pairs hydrogen bond covalent bond
  9. 9. ∗ If the sequence of bases on one strand of a DNA molecule is TCGAACTGA, the sequence on the other (complimentary) strand is: Practice Base Pairing
  10. 10. ∗ Why does DNA replicate? (Hint: Think back to Mitosis) ∗ DNA is replicated in the S phase of the cell cycle, before the cell divides. 12.3 DNA Replication
  11. 11. ∗ Step 1 ∗ The DNA double helix unwinds ∗ DNA helicase (enzyme). ∗ breaks the H bonds between the bases. ∗ The areas where the double helix separates are called replication forks. Copying the Code
  12. 12. ∗ Step 2 ∗ DNA polymerase (enzyme) moves along each DNA strand adding complimentary bases according to the base pairing rules. ∗ DNA polymerase also proofreads the DNA molecule to reduce errors.
  13. 13. ∗ Step 3 ∗ The process continues until all of the DNA has been copied. ∗ DNA polymerase detaches.
  14. 14. ∗ This process produces two DNA molecules each composed of one new and one original strand. ∗ Both DNA molecules produced are identical to each other. ∗ DNA replication takes place at many points on a eukaryotic chromosome. ∗ Allows replication to happen more quickly.

×