DNA Deoxyribonucleic Acid

DNA facts DNA is located in the nucleus of the cell DNA carries all the information that cells need to function The information is in code and is different in every organism

DNA Structure DNA is shaped like a twisted ladder (double helix) Rungs are made of four kinds of nitrogen bases that form pairs, adenine, guanine, cytosine, and thymine Adenine pairs with Thymine A-T Cytosine pairs with Guanine C-G Sides are made of a sugar called deoxyribose connected with phosphates The order of the rungs of the ladder form the “code” of instructions and is different for every person

History of DNA Rosalind Franklin Worked on X-ray diffraction pictures Photographed DNA in 1950’s - formed a basis for confirming structure of DNA

History of DNA Maurice Wilkins Worked for 10 years on making a model of the DNA molecule His work with X-ray diffraction was instrumental in inspiring James Watson Shared Nobel prize with Watson and Crick

History of DNA James Watson Francis Crick Watson and Crick developed a model of the DNA molecule in 1953 –confirmed by Franklin’s picture Received the Nobel prize in 1962

DNA replication (copying) The rungs of the ladder “unzip” and new nitrogen bases are added to the ladder. http://www.youtube.com/watch?v=zdDkiRw1PdU

Making a DNA model In this activity you will make a model of a DNA molecule – just like Watson, Crick and Wilkins. Color T blue, A red, G yellow, C green Color phosphates orange Color sugar gray Cut out and assemble the model

Questions to answer Use your text pg135-136 Name the nitrogen bases. What do the letters C, T, G, A stand for? Which nitrogen base pairs with Cytosine? Which nitrogen base pairs with Adenine? Describe how the DNA molecule replicates (copies itself). Draw the replication process