1. DNA DeoxyriboNucleic Acid

2. DNA is the Genetic Material of Chromosomes http://www.pbs.org/wgbh/no va/genome/program.html

3. Levels of Structure Chromosomes are long DNA molecules packed together DNA is composed of 2 strands Each strand is a long string of nucleotides Journey into DNA http://www.pbs.org/wgbh/no va/genome/dna.html#

4. DNA is the blueprint Contains the codes for what makes us… us We are really just scratching the surface in understanding the ways DNA works

5. Some basics about DNA We have a lot of it- every cell contains about 6.5 feet of DNA (if you were to run each molecule end to end) The total length of DNA in our body would go the sun and back ▫70 times! ▫We’ll extract our DNA the Monday after Spring Break

6. Our Understanding of It Is Changing Rapidly Old ViewNew View DNA is mostly genes Each segment of DNA is a gene that codes for a protein Rest of DNA is “junk” <1% of DNA are actually coding genes The rest controls the expression of genes or play as-of- yet undiscovered roles

7. What We Have a Good Understanding Of The structure of DNA (shape, how it is stored etc.) How DNA is replicated How proteins are made from genes The sequence of DNA

8. What We Barely Understand What causes genes to be activated or expressed What the 99% of DNA does or why it’s there Genetic links in things like heart disease/cancer How the environment affects our DNA How DNA came to be, chromosome came to be etc. Much, much more

9. Our Knowledge of DNA is Changing RAPIDLY! Our understandings now is very different from when I was in college which is different from when I was in HS. Our understanding will have changed if you take biology in college

10. The Structure of DNA (DEOXYRIBOSE NUCLEIC ACID) A. DNA is a macromolecules called NUCLEIC ACIDS. The other type of molecule in this category is RNA.

11. DNA Structure Theorized to be a double helix consisting of 2 strands wrapped around each other Discovered by Watson and Crick AND Rosalind Franklin

12. Rosalind Franklin Provided the scientific evidence that allowed Watson and Crick to suggest the double helix Often goes uncredited and since she had died – couldn’t share in the Nobel prize

13. Remember… Since DNA is a macromolecule (POLYMER), it is really made of many (in this case billions) smaller molecules (MONOMERS!) put together. The DNA monomer is the individual NUCLEOTIDE.

14. Nucleotide A single piece of the DNA strand Made of 3 parts ▫Deoxyribose (sugar) ▫Phosphate ▫Base (A,G,C or T)

15. PurinesPyrimidines Adenine Guanine CytosineThymine Phosphate group Deoxyribose DNA Nucleotides

16. The backbone of 1 strand Alternates between the sugar (deoxyribose) and the phosphate group The base sticks out into the middle

17. Double-Stranded The bases hydrogen bond with each other to hold the strands together The base from one strand bonds with the base from the other forming a complementary base pair a. ADENINE bonds with THYMINE b. GUANINE bonds with CYTOSINE They coil into a double-helix

18. Hydroge n bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Figure 12–7 Structure of DNA Section 12-1

19. What about the structure of DNA makes us unique???  ORDER OF BASE PAIRS  http://www.pbs.org/wgbh/nova/genome/program.html genetic variation http://www.pbs.org/wgbh/nova/genome/program.html

20. What You Should Know about DNA structure The basic structure of a nucleotide The basic structure of DNA How DNA and RNA differ Base-pair rules How the structure suggests a replication method