1. DNA and Replication

2. What is the function of deoxyribose nucleic acid (DNA)?
It stores and transmits genetic information.
Found in the nucleus, on chromosomes.

3. Who discovered DNA?

4. James Watson and Francis Crick
James Watson and Francis Crick. They built a model of DNA using X-ray diffraction photographs by Rosalind Franklin and data from Maurice Wilkins.

5. What is DNA made of?
DNA is made of nucleotides

6. What are 3 parts of nucleotides?

7. A. Deoxyribose A 5-carbon sugar
Part of the “side of the ladder/staircase”

8. B. A phosphate group Also part of the “side of the ladder”
Alternates between the deoxyribose sugar

9. C. Nitrogen bases
Purines: Adenine & Guanine; bases that have two rings of carbon & nitrogen atoms
Pyrimidines: Thymine & Cytosine; bases that have one ring of carbon & nitrogen atoms
Adenine always pairs with Thymine; Guanine always pairs with Cytosine (complementary base pairing)
The “rungs” of the ladder

10. What is DNA replication?
A process of copying DNA in a cell.

11. What are the steps of replication?
1. Hydrogen bonds between base pairs are broken.
2. The Helix opens
3. Free-floating nucleotides pair with exposed bases.
4. The bonds re-form and the helix coils
5. Each daughter molecule consists of one parent strand and one newly formed strand.

12. What is a mutation? Any change in the DNA sequence
There are two types: chromosomal mutations and point (gene) mutations

13. What are some factors that can cause mutations?
Chemicals, radiation, and high temperatures