1. DNA & Replication Headings Vocabulary Important Words

2. CHROMOSOME CHROMATIN DNA NUCLEUS

3. Structure of DNA (DeoxyriboNucleic Acid) Using critical info from the work of others (Rosalind Franklin & Linus Pauling)…Rosalind Franklin James Watson & Francis Crick made 1 st model of DNA in 1953 DNA is a Nucleic Acid (AKA: Organic Compound) DNA is made up of small subunits called: Nucleotides

4. DRAW THIS IN YOUR NOTES! “YES, THE ENTIRE PICTURE!!!”

5. Each nucleotide is made up of: Deoxyribose (sugar) Phosphate group (“P”) Nitrogen Base (4 types) Adenine- A Thymine-T Cytosine- C Guanine-G What Makes Up DNA? Purines Pyrimidines Purines Pyrimidines

6. 2 long chains of nucleotides Joined together in the form of a ladder Ladder is twisted in the form of a double helix or spiral What Is the “Ladder”?

7. Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G) Structure of DNA

8. Sides of the Ladder = Alternating Deoxyribose (Sugar) & Phosphate s-P-s-P-s-P-etc. RungsStepsRungs or Steps of ladder = Pairs of Nitrogen Bases A-T or C-G T-A or G-C

9. Adenine(A) pairs up w/ Thymine(T) Guanine(G) pairs up w/ Cytosine(C) Example: A G C T A CG C A 5’ T C G T C G A T GA T GC G TC G T 3’ How Do Nitrogen Bases Pair Up? 3’ 5’

10. All organisms have the same type of nucleotides Nucleotide arrangement provides for all the different types of organisms Ex: A mouse and a rosebush have the same nucleotides…but… Different Nucleotide Order = Different Organism!!! *This sequence of nucleotides = GENETIC CODE Why Do Organisms Look So Different?

11. Replication of DNA copyDuring cell division a copy of DNA must be made exact copyWhen new cells are formed each new cell gets an exact copy of the genetic information. Replication.This copy of DNA is made through a process known as Replication.

12. Let’s see DNA Replication at Work!

13. Steps of Replication During replication, each strand serves as a pattern to make new DNA molecule. 1.The 2 nucleotide strands separate at base pairs. DNA Helicase (enzyme)They unzip like a zipper using DNA Helicase (enzyme) 2.Each strand then builds its opposite strand by base pairing with nucleotides that float freely in the nucleus. 3.Each new DNA molecule has 1 nucleotide strand from the original DNA molecule and 1 nucleotide strand made from free nucleotides in the nucleus.

14. DNA Replication Growth Replication fork DNA polymerase New strand Original strand DNA polymerase Nitrogenous bases Replication fork Original strand New strand