Set up Cornell Notes on pg. 93 Essential Question :

1. 8.2 Structure of DNA 2.1 Atoms, Ions, and Molecules • Set up Cornell Notes on pg. 93 • Essential Question: Explain the base-pairing rules. How many types of nucleotides are there? How do they differ? Explain the base-pairing rules. How many types of nucleotides are there? How do they differ? Key Concept:DNA structure is the same in all organisms NOTEBOOKS DUE IN 20 MINS

2. KEY CONCEPT DNA structure is the same in all organisms.

3. phosphate group nitrogen-containing base deoxyribose (sugar) DNA is composed of four types of nucleotides. Draw and label on p.92 • Each nucleotide has three parts. 1. a phosphate group 2. a deoxyribose sugar 3. a nitrogen-containing base base 1 3 2 backbone Covalent bonds

4. The nitrogen containing bases are the only difference in the four nucleotides. BASES • Thymine- T • Adenine- A • Guanine- G • Cytosine-C

5. Watson and Crick determined the three-dimensional structure of DNA by building models. • They realized that DNA is a double helix • backbone on the outside • bases on the inside. bases backbone

6. Watson and Crick’s discovery built on the work of Rosalind Franklin and Erwin Chargaff. • Franklin’s x-ray images suggested that DNA was a double helix of even width. • Chargaff’s rules stated that A=T and C=G.

7. G C A T Nucleotides always pair in the same way. • Apairs with T • C pairs with G • the helix has a uniform width. • Ex: ladder

8. hydrogen bond covalent bond • The backbone is connected by covalent bonds. • The bases are connected by hydrogen bonds. Hydrogen bond backbone Bases (A,T,G,C)

9. A T C G C G A T T A G C

10. Using the base pairing rules- complete the DNA strand: GATTACAATCGATCGAT CTAATGTTAGCTAGCTA TAGGACTACTAGTCGTA ATCCTGATGATCAGCAT

11. Have Your DNA & Eat It Too Adenine (A) = Green Thymine (T) = Pink Cytosine (C) = Yellow Guanine (G) = Orange ONLY GET 6 of each marshmallow

12. DNA Coloring Activity Color Key: A = red B = dark blue C = green D = yellow E = orange F = light blue G = brown