1. Unit 5: DNA Section 1

2. Vocabulary Nucleotide- –monomer of a nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base. Base-pairing- –princple that bonds in DNA can form only between adenine and thymine and between guanine and cytosine.

3. Yes I can explain that!!! I can explain the three parts of a nucleotide. I can explain which bases match up.

4. But first, let’s read!! An article about the discovery of DNA!! Please do the following… –Underline important words. –Highlight main ideas –Write a 5 sentence summary of what you read!!!

5. 1.The Double Helix a.James Watson & Francis Crick used the x-ray from Franklin to make a 3- dimensional model showing the structure of DNA b.It was a double helix (two strands wound like a spiral staircase) c.Watson & Crick discovered that hydrogen bonds held the strands together d.Base pairing: Bonds held A to T and G to C (no intermixing)

6. What is DNA??? 2.DNA is a long molecule made of nucleotides (3 parts) a.5-carbon sugar = deoxyribose b.Phosphate group c.Nitrogenous base PurinesPyrimidines Adenine Guanine CytosineThymine Phosphate group Deoxyribose

7. 3.There are four bases a.Adenine and Guanine (purine group) b.Cytosine and Thymine (pyrimidine group) 4.Chargaff’s Rules a. [A] = [T] and [G] = [C] PurinesPyrimidines AdenineGuanine CytosineThymine Phosphate group Deoxyribose

8. Hydrogen bonds Nucleotide Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

9. Let’s Review https://www.youtube.com/watch?v =wdhL-T6tQcohttps://www.youtube.com/watch?v =wdhL-T6tQco After watching the video, add in any facts that you did not have from before.