1. DNA – Show Me What You’re Made of!!

2. DNA, or deoxyribonucleic acid, resides inside the nucleus of every living cell.
The shape is described as a twisted ladder or DOUBLE HELIX.

3. The sides of the ladder are made of deoxyribose sugar (D) and phosphates (P).
The steps of the ladder are made up of matching pairs of molecules called nitrogen bases.

4. There are 4 kinds of nitrogen bases: Adenine (A) Thymine (T)
Cytosine (C)
Guanine (G)
ADENINE ONLY pairs with THYMINE
CYTOSINE ONLY pairs with GUANINE A C G T

5. A nitrogen base + sugar + phosphate makes up a nucleic acid hence the name…
Deoxyribo(sugar)nucleic acid (phosphate + nitrogen base) DNA

6. In 1950, Erwin Chargraff analyzed the base pair composition of DNA.
He discovered that:
% ADENINE = % THYMINE
AND
% CYTOSINE = % GUANINE

7. Meaning, there is the same amount of Adenine and Thymine
there is the same amount of Cytosine and Guanine
providing evidence that they pair with one another.

8. Using the rules, create a complimentary strand of DNA using the strand provided below.
Now, using Chargraff’s rules, determine the percentage of:
____% Adenine = ____% Thymine
____% Cytosine = ____% Guanine 30 30 20 20