1. Science Log: DNA Bubble Map
Pg. 23 in your science log section

2. DNA Structure:
What does DNA look like?

3. What are genes?
Passed from one generation to the next (determine inherited characteristics, such as eye color)
Found on chromosomes (which are made of DNA)
Contain the information to:
Build and maintain cell parts
Be copied each time a cell divides (The Cell Cycle)

4. DNA’s parts DNA is made of NUCLEOTIDES Each nucleotide has: Sugar
Phosphate
Base containing nitrogen

5. 4 types of bases There are 4 types of bases
Adenine
Thymine
Guanine
Cytosine
In the 1950s, Chargaff discovered that the amount
of A and T are equal and G and
C are equal. (Chargaff’s Rules)

6. Rosalind Franklin
British scientist who used x-ray images to determine the spiral shape of DNA

7. Watson and Crick’s Model
Watson and Crick studied the work of Chargaff and Franklin to determine the structure of DNA
Figured that it is a “double helix”:
Twisted ladder

9. How does DNA replicate? Replicate = copy
Watson and Crick also figured out how DNA replicates!
Steps to replicate:
“Double Helix” unwinds
Ladder unzips
New nucleotides come in to make two new strands

10. Steps to replicate: 1. “Double Helix” unwinds and unzips
Enzyme (chemical) called helicase does this

11. Next, the exposed bases on each strand find new nucleotide partners

12. The end result!