1. Structure of DNA

2. Function of DNA DNA is the genetic material of the cellDNA is the genetic material of the cell The structure of DNA must allow:The structure of DNA must allow: – the storage and transmission of genetic information –exact replication to occur.

3. Genes code for proteins Genetic information must tell cells how to make proteins.Genetic information must tell cells how to make proteins. –Sections of the DNA called genes code for one protein –Proteins form structures and control chemistry of cell. Think: Proteins are made in the cytoplasm but DNA remains in nucleus. How do you think that works?

4. DNA Structure DNA is a polymer.DNA is a polymer. The monomer of DNA is called a nucleotide.The monomer of DNA is called a nucleotide. Nucleotides linked together to form the sides of the DNA molecule.Nucleotides linked together to form the sides of the DNA molecule. DNA molecule has shape of a double helix.DNA molecule has shape of a double helix. –The sides are anti-parallel. deoxyribonucleic acid

5. What ’ s in a name? One 5 carbon sugar called deoxyribose.One 5 carbon sugar called deoxyribose. –“Deoxy” = one less oxygen. –“ribo” = than ribose. Deoxyribonucleic acidDeoxyribonucleic acid –“nucleic” = found in nucleus. –“acid” = acidic Deoxyribose, a pentose sugar, has each carbon numbered.

6. Nucleotide Structure Phosphate group attached to the #5 carbon of the sugar.Phosphate group attached to the #5 carbon of the sugar. One nitrogenous base attached to the #1 carbon in the sugar.One nitrogenous base attached to the #1 carbon in the sugar. Purines -2 ringsPurines -2 ringsAdenineGuanine –Pyrimidines -1 ring CytosineThymine Four bases of DNA Think: how will you recognize the name of a base on a quiz?

7. Complementary base pairing rules Nitrogenous bases form rungs of the helix. –Adenine (2 rings) is bonded with Thymine (1 ring) using 2 hydrogen bonds. (A-T) –Guanine (2 rings) is bonded with Cytosine (1 ring) using 3 hydrogen bonds. (G-C) Think: how will you remember which bases pair with each other?

8. Summary questions 1.Name 2 functions of DNA 2.Who discovered the structure of DNA? 3.What are the 4 base pairs. 4.What is the structure if DNA?