The Structure of DNA

The Backbone Phosphorous Carbohydrate (sugar) Ring

Deoxyribonucleic Acid DNA The carbohydrate ring on the DNA is DEOXY There is a hydrogen instead of a hydroxyl group on the carbohydrate ring. If there is a hyrdoxyl group it is called a ribonucleic acid. RNA DNA RNA

The Backbone The phosphorus group and carbohydrate ring link together to make the backbone of DNA What other part are we missing to DNA?

Nucleotides There are 4 nucleotides in DNA. Does anyone remember what they are? Adenine [A] Thymine [T] Guanine [G] Cytosine [C]

Purines and Pyrimidines Purine Adenine and Guanine Pure As Gold Purines have a 2 ring structure Gold has twice the value of rocks Pyrimidine Thymine and Cytosine Pyrimidines have a one ring structure

Chargaff’s Rule Do you remember Watson and Crick? They used Chargaff’s Rule and the double helix structure of DNA to figure out that: AND THIS IS IMPORTANT Adenine PAIRS with Thymine Cytosine PAIRS with Guanine

Was that a Lot? Let’s Review Please make sure all of this is in your notes!!!! What 2 things make up the backbone of DNA? What does Deoxy mean? What are the 4 nucleotides? What is the difference between a Purine and a Pyrimidine? Which nucleotides are Purines? Which are Pyrimidines? Which nucleotide pairs with witch other one?

Now Let’s Make our Own DNA Cut out some nucleotides. Use one color for each type It’ll help a lot if you cut out equal numbers of C’s and T’s and equal numbers of A’s and G’s. You’ll want about 20 nucleotides in total! Label these nucleotides with their proper letters. Label them as purines and Pyrimidines Pu or py Cut out a DNA backbone from the other color. (Just make it a long rectangle for simplicity) Glue ONE STRAND (1 backbone+about 10 nuceltides in any sequence) on the sheet of white paper Then give your sheet to a partner and have them write their name on it and COMPLETE the second strand of DNA. Glue it and hand it in.