Take the Following Colored Pencils To Your Seat:

1. Take the Following Colored Pencils To Your Seat: • Orange • Green • Purple • Yellow • Red • Blue • Black

2. DNA & Genes CHAPTER 11

3. Objectives • Analyze the structure of DNA. • Determine how the structure of DNA enables it to reproduce itself accurately.

4. 1952: experimented to show that DNA, not protein, is the genetic material How did they show this? Used bacteriophages (virus that infects bacteria) 1 bacteriophage made of only radioactive protein 1 bacteriophage made of radioactive DNA Only the ones with DNA produced new viruses Hershey & Chase

5. NITROGEN BASES: • Adenine • Guanine • Thymine • Cytosine PURINES PYRIMIDINES DNA Structure • Polymer of repeating subunits: NUCLEOTIDES • Sugar (deoxyribose) + phosphate + base

6. 1953: James Watson and Francis Crick published their DNA experiment DNA is made of 2 chains of nucleotides held together by nitrogenous bases DNA is shaped like a long zipper that is twisted into a coil like spring  shape is called a double helix DNA Structure

7. Double stranded Alternating sugar/phosphate backbone held together by covalent bonds Bases attach to the sugar Bases are on the interior of the double strand like teeth in a zipper. DNA Structure

8. Chargaff’s Rule • Purine will always pair with a pyrimidine A T C G * In DNA, the amount of adenine (A) is ALWAYS equal to the amount of thymine, and the amount of guanine is ALWAYS equal to the amount of cytosine The 2 chains of nucleotides in DNA are held together by hydrogen bonds. Cytosine forms 3 hydrogen bonds with guanine, and thymine forms 2 hydrogen bonds with adenine

9. Complementary base paring produces a long, 2 stranded molecule that is often compared to a zipper. The sides of the zipper are formed by the sugar and phosphate units, while the teeth of the zipper are the pairs of bases Sugar-Phosphate Backbone In each chain of nucleotides, the sugar of one is joined to the phosphate group of the next nucleotide by a covalent bond Hydrogen bonds between nitrogen bases

10. DNA Replication Section 11.1

11. Recall: During interphase, DNA replicates itself. Without DNA replication new cells would only have ½ the DNA of their parents Species could not survive and individuals could not grow or reproduce successfully. Mitosis/Meiosis

12. Copying DNA • Replication of DNA • Strands of double helix are complimentary • base pairing allows each strand to serve as a template for a new strand • new strand is 1/2 parent template & 1/2 new DNA Animation

13. Replication: 1st step • Strands are separated DNA • helicase enzyme • unzips part of DNA helix by breaking hydrogen bonds. • stabilized by single-stranded binding proteins helicase single-stranded binding proteins replication fork

14. Replication: 2nd Step • Each side replicates the other with the help of DNA Polymerase (enzyme used to extend the strand of DNA). • Adding bases • can only add nucleotides to 3 end of a growing DNA strand • strand only grows 53

15. Replication: 3rd Step • The lagging strand is synthesized discontinously. • Primase, RNA primer, synthesizes a short segments of DNA (Okazaki Fragments) extended by DNA polymerase

17. Animation

18. Result • Two DNA molecules identical to the original and each other are made