Chapter 28 DNA-Life’s Code Learn the parts of DNA Understand DNA replication Understand how DNA mutates Biotechnology

Bacterial Transformation Experiment Fred Griffith 1928 Injected mice with bacteria Smooth:pneumonia bacteria Rough: harmless bacteria

Transforming Principle Chemical that causes harmless bacteria to transform into pneumonia Transforming principle = DNA

DNA Chemical of heredity Deoxyribonucleic Acid 1.Sugar (Deoxyribose) 2.Phosphate 3.Nitrogen Base

Nucleotide 3 parts combined into one subunit Join together to form an entire DNA

4 Nitrogen Bases 1.A: adenine 2.G: guanine 3.T: Thymine 4.C: Cytosine

Base Pairing Only certain bases can bond with one another 1.A bonds T 2.G bond C

DNA Structure Double Helix = twisted ladder 2 chains: nucleotides joined together Rungs: base – hydrogen bond – base Sides: sugar and acid

Replication of DNA Copies of DNA chain made during Interphase

Steps to Replication 1.An enzyme “unzips” the double helix 2.Unzips by breaking Hydrogen bonds 3.A new enzyme moves along the parent chain placing new nucleotides 4.Match base pairs; A-T; G-C 5.DNA molecule is a parent chain bonded to a new chain