Warm Up:Warm Up: Take out homework.What is the shape of DNA?Where is DNA found in cells?What is the monomer (building block) of nucleic acids (macromolecule)?

• Homework:Homework: Complete DNA completion worksheet (only side 1)

http://ed.ted.com/lessons/dna-the-book-of-you-joe-hanson

http://www.wired.com/science/discoveries/commentary/dissection/2008/04/dissection_0418

The 5-carbon sugar may be different in other nucleic acids. The sugar in DNA is deoxyribose.

3 PARTS:

1. Sugar Molecule – deoxyribose

2. Phosphate Group – phosphorous(P) and oxygen (O)

3. Nitrogen Base – adenine(A), cytosine(C), guanine(G), and thymine(T)

• One strand can be a “template” to find the code of the other, but they are NOT identical– Which bases are

complements?– Chargaff’s Rules

of Base Pairing

“Sugar-phosphate backbone”The phosphate of one nucleotide is bonded to the sugar of the next.HYDROGEN BONDS!!!

Draw the complementary strand of the following DNA template.

A Twisted Ladder

• Complementary strands are held together by hydrogen bonds

Write answers on whiteboards:Write answers on whiteboards:

1. Draw and label the monomer of a Nucleic Acid.

2. What makes each nucleotide different? Name the 4 nucleotides.

3. Identify the complementary base pairs4. What is the “bond” that holds the

complementary DNA strands together?5. What molecules make up the “backbone”

of DNA?

Brain Pop!!Brain Pop!!

Build a model of DNABuild a model of DNA

• Make 9 base pairs!!!Make 9 base pairs!!!• Blue tubes = cytosine

• Yellow tubes = guanine

• Green tubes = thymine

• Orange tubes = adenine

• White tubes = phosphates

• White rods = hydrogen bonds

• Purple or black pentagons = deoxyribose (sugar)