1. Chapter 10 Notes Structure of DNA

2. DNA is Made up repeating units of nucleotides Three parts of a Nucleotide are: 1. Deoxyribose sugar 2. Phosphate group 3. Nitrogen-containing base

3. Nitrogen Containing Bases

4. Base Pairing Rules Adenine pairs with Thymine (2 hydrogen bonds) Guanine pairs with Cytosine (3 hydrogen bonds) Chargaff’s Rule: The amount of adenine always equals the amount of thymine, and the amount of guanine equals cytosine.

5. The Double Helix Double stranded, coiled like a spiral stair The backbone of the strands are alternating phosphate and deoxyribose sugars

6. Histones DNA is tightly coiled around proteins called histones to make the long DNA molecule easier to manage.

7. What are the three parts of a nucleotide?

8. What Base Bonds to Adenine?

9. What Base Bonds to Guanine?

10. Assignment Class work: DNA Book– cover page and page 1 (Due tomorrow) Homework: PQRST pg. 200- 203 (due Friday)

12. Purpose of DNA Replication Why would DNA replicate? When would DNA replication occur? To make a copy of it’s DNA for the cell to divide. Mitosis

14. Steps of DNA Replication 1. Helicase unzips and unwinds the DNA strands by breaking the hydrogen bonds

15. Steps of DNA Replication 2. Enzymes called DNA Polymerase add complementary nucleotides.

16. Steps of DNA Replication 3. Process continues until entire strand is copied Result is two strands of DNA

17. AA TCC AAA G A TTTTT GG C 1. First the DNA must unzip: Enzymes split apart the base pairs and unwind the DNA.

18. AA TCC AAA G A TTTTT GG C

19. AA TCC AAA G A TTTTT GG C

20. AA TCC AAA G A TTTTT GG C T T 2. Bases pair up: Free nucleotides in the cell find their complementary bases along the original strand.

21. AA TCC AAA G A TTTTT GG C T A CT

22. AA TCC AAA G A TTTTT GG C T A CT A T

23. AA TCC AAA G A TTTTT GG C T A CT A T C G

24. AA TCC AAA G A TTTTT GG C T A CT A T C G A C A T G TT G

25. AA TCC AAA G A A TTTTT GG C T A CT A T C G A C A T G TT G A

26. AA TCC AAA G A A TTTTT GG C T A CT A T C G A C A T G TT G A The DNA is now duplicated:

27. End Result Two identical molecules of DNA They have one new and one old strand

28. Mechanism of DNA Replication DNA is said to be semiconservative since each new DNA molecule made has one parent strand and one daughter strand. Can also be said: one old strand and one new strand

29. Accuracy and Repair Copies must be 100% accurate Mutation= change in nucleotide at one location Enzymes proofread and fix errors

30. Class work Homework DNA Replication worksheet 1. Answer questions at the top 2. Use page 201 to create a labeled drawing of DNA Replication with descriptions of each step Page 2 of DNA Book (due Monday) PQRST (due tomorrow)