1. DNA Structure and Replication
Biology
Spring 2017

2. DNA Deoxyribonucleic acid
Genetic material that carries information about an organism from one generation to the next
DNA is found in the chromatin in the nucleus.

3. DNA Structure A DNA molecules looks like a twisted ladder
It is made up of units called nucleotides.
Each nucleotide is made up of 3 components:
Deoxyribose- a 5-carbon sugar.
Phosphate group- makes up the “sides of the ladder.
Nitrogen base- makes up the “rungs” of the ladder.

4. Nitrogen Bases DNA has 4 kinds of nitrogen bases: Adenine Thymine
Guanine
Cytosine

5. DNA Structure Side note: Adenine ONLY pairs with Thymine
Guanine ONLY pairs with Cytosine
How to remember it:
A+T spells the word “AT”
G and C is what’s left.

6. Chargaff’s Rule

7. DNA Replication
During DNA replication, a DNA molecule “unzips” between it’s paired bases.
New bases pair up with bases on an old strand.
This forms two identical DNA strands.

8. DNA Replication Video