DNA What does DNA mean? Where do I find DNA? Why is it important? How do I use DNA?

DNA Information DNA *stands for deoxyribonucleic acid. *makes up chromosomes w/proteins. *located in the nucleus. *NEVER leaves the nucleus. *is passed from one generation to the next in chromosomes. *looks like a ladder, twisted around itself, called a “double helix”

DNA Timeline Facts… Early 1950’s 1 st picture of DNA taken by Rosalind Franklin using an X-ray machine.

DNA Timeline Facts… 1953 DNA structure discovered by James Watson & Francis Crick. Francis CrickJames WatsonRosalind Franklin 1962 Watson, Crick and Franklin received Nobel Prize in Medicine. “FATHERS OF DNA” “Watson & Crick”

Gene def: a short, active section of DNA, that contains the instructions (code) for building all proteins. *the code (directions for building the protein) is the order of bases on DNA. *Each chromosome is made up of many hundreds of genes. *Each gene is made up of hundreds or thousands of bases long. Eye color geneDimples gene Hair color gene

DNA Structure - is composed of many small subunits called “nucleotides” Nucleotides are made up of 3 parts: 1.a phosphate 2.deoxyribose sugar 3.nitrogen containing base Nucleotides are held together by covalent, ester bonds. *The ladder shape is formed by linking matching bases together.

*MAJOR TYPE* I. Purines (Two ring bases in DNA) A.Adenine B.Guanine *MAJOR TYPE* II, Pyrimidines (One ring bases in DNA) A. Cytosine B. Thymine Nitrogenous Bases in DNA 1.Adenine 2.Guanine 3.Cytosine 4.Thymine

Complementary Base Pair Rules: says, “Each base has a complement or partner in DNA.”. *Adenine only bonds w/ Thymine *Guanine only bonds w/ Cytosine *Hydrogen bonds between the bases hold the strands together.

DNA - double helix P P P O O O P P P O O O G C TATA 2 Spirals wound around each other

Shape of DNA The ladder is twisted into a shape scientists call a “Double Helix”