1. NOVEMBER 2 ND 2015 MOLECULAR GENETICS

2. Reminder: My name is Ms. M! (M for McAvella) Feedback Box University Inquiries GENERAL ANNOUNCEMENTS

3. KW CHART! Form groups of 4 On your chart paper, create the following table: K know In the K column, list everything you and your group members know about the topic Wwould like to know In the W column, list everything you would like to know about the topic GENETICS KW E.g. Our genes contribute to what make us different from one another E.g. What diseases/disorders are genetically related?

4. LEARNING GOALS nucleotides Students will learn about nucleotides, the monomer of DNA molecules, and how they are bound to form strands complementary base pairing double helix Students will understand how complementary base pairing can lead to the formation of two polynucleotide strands that twist to form a double helix

5. WHAT IS DNA? Deoxyribonucleic acid (DNA) DNA is the hereditary material – passed on from generation to generation Contains information that controls the production of proteins Has to be able to replicate itself with great accuracy

6. STRUCTURE OF DNA Structure: DNA is made up of repeating units of nucleotides (monomer) Nucleotides are composed of the following 3 components: 1. A sugar group 2. A phosphate group 3. A nitrogenous base

7. 1. SUGAR GROUP In DNA, the sugar group is a deoxyribose sugar The sugar group is a five-carbon molecule

8. 2. PHOSPHATE GROUP The deoxyribose sugar binds with phosphate at both its 3’ and 5’ (three prime and five prime) carbons

9. 3. NITROGENOUS BASE A nitrogenous base attaches to the deoxyribose sugar group There are two different forms of nitrogenous bases: 1. Pyrimidines 2. Purines

10. 3. NITROGENOUS BASE Thymine and Cytosine are pyrimidines Adenine and Guanine are purines

11. PYRIMIDINES – CHEMICAL STRUCTURE Thymine and Cytosine Have a single ring

12. PURINES – CHEMICAL STRUCTURE Adenine and Guanine Have two fused rings

13. DNA NUCLEOTIDE* Recall: consists of a phosphate group, sugar group and nitrogenous base

14. DRAW A NUCLEOTIDE

15. NUCLEOSIDE VS. NUCLEOTIDE A sugar + a nitrogenous base = nucleoside A sugar + a nitrogen base + phosphate = nucleotide Phosphorylating a nucleoside makes a nucleotides

16. PRIMARY STRUCTURE Each nucleotide is attached to the next by a phosphodiester bond The phosphodiester bond is the linkage between the 3’ carbon atom of one sugar molecule and the 5’ carbon atom of the next Think: Phospho (phosphate) + diester (two esters) This bonding creates a polynucleotide (multiple nucleotides) strand

17. DRAW

18. SUGAR PHOSPHATE BACKBONE Each polynucleotide strand has a backbone of alternating phosphate groups and sugars called the sugar phosphate backbone

19. BINDING OF TWO STRANDS Complementary base pairing : nitrogenous bases on opposite strands pair through hydrogen bond formation such that Adenine pairs with Thymine Cytosine pairs with Guanine A-T held by 2 hydrogen bonds C-G held by 3 hydrogen bonds Question: Which pair do you think is stronger?

20. CHARGAFF’S RULE The amount of adenine in any sample of DNA is equal to the amount of thymine AND The amount of cytosine is always approximately equal to the amount of guanine Question: are purines binding to one another and pyrimidines binding to one another?

21. ANTIPARALLEL Antiparallel: The two strands run in opposite directions Each strand will have a 5’ end and a 3’ end The 5’ end of one strand lies across from the 3’ end of the complementary strand The 5’ and 3’ come from the numbering of the carbons on the deoxyribose sugar

22. ANTIPARALLEL – ANALOGY This is similar to how sports teams face in a different direction when they shake hands at the end of a game Let’s say the goalie is always at the front of the line (5’) And the coach is always at the back of the line (3’)

23. DRAW

24. SECONDARY STRUCTURE – DOUBLE HELIX The two bound polynucleotide strands twist around each other to form a double helix http://www.johnkyrk.com/ http://www.dnatube.com/video/3447/DNA-double- helix

25. LEARNING GOALS Students will learn about nucleotides, the monomer of DNA molecules, and how they are bound to form strands Students will understand how complementary base pairing can lead to the formation of two polynucleotide strands that twist to form a double helix

26. QUESTIONS! How many bonds between A-T? C-G? What kind of bonds are these? What is a nucleotide and what is a nitrogenous base? Are the two polynucleotide strands that twist around each other identical?

27. ROSALIND FRANKLIN* In groups of 4/5 you will read a short section on an article about Rosalind Franklin The sections are as followed: 1. A crucial contribution 2. Her education 3. A passionate woman 4. An unhappy time 5. On to better things Summarize an important fact or two about the section you read Pick one group member to read this to the class

29. TOMORROW: DNA EXTRACTION! You can read through the instructions tonight if that would help you in working your way through the mini-lab