DNA Deoxyribonucleic Acid

Importance of DNA DNA is the code for making proteins Those proteins control your physical features The directions for making your proteins is found on the chromosomes in the sequence of DNA

Where is DNA? Found Inside the Nucleus Found Inside the Nucleus Chromosomes contain DNA and protein molecules

History of DNA Rosalind Franklin took x-ray diffraction pictures that led to the discovery that DNA was a double helix Erwin Chargaff discovered that bases were paired Adenine to Thymine and Guanine to Cytosine

History of DNA James Watson and Francis Crick Built the first model of DNA in 1953

Structure of DNA Looks like a twisted ladder called a Double Helix

Contains 3 parts: bases, sugar, phosphate Sides of Ladder Phosphate Sugar (Deoxyribose) Rungs of the ladder Nitrogen bases Nitrogen bases Adenine –Thymine Adenine –Thymine Cytosine – Guanine Bases attached to sugar

DNA Replication (making copies) 1.Untwists 2.Unzips down the middle into 2 pieces breaks between nitrogen bases 3.Free bases made in the cytoplasm join their compliments (A with T, G with C) 1.Zips back up 2.Twists As a result you have two new strands of DNA identical to the parent