1. Unit 4 Notes: DNA Structure

2. (1) What is DNA? DNA = DeoxyriboNucleic Acid
Stores genetic instructions for producing proteins.
Stored in the Nucleus of Eukaryotes.

4. (2) DNA Nucleotide A nucleotide is the monomer for DNA. Structure:
Phosphate
Deoxyribose Sugar
Nitrogenous Base
Looks Like:

5. (3) Overall DNA Structure
Double stranded
Helix
Outside / Backbones Made Of:
Alternating Phosphates and Sugars
Inside / Steps Made of:
Nitrogenous Bases

6. (Yes You Need To Draw This…)

7. (4) Base Pairing:
A—T
A = Adenine
T = Thymine
G—C
G = Guanine
C = Cytosine
Base Percentages:
% of A = % of T
% of G = % of C
(A and T) + (G and C) = 100%
EXAMPLE: Within the DNA of yeast cells, it is found that 16% of the bases are Adenine…
What % are Thymine?
What % are Guanine or Cytosine?

8. (5) Anti-Parallel Strands
Anti-Parallel = 2 Lines going in opposite directions!
Anti = Without or Opposite
Parallel = Going the SAME Direction
One Strand goes 5’  3’… and the other starts at 3’  5’…
The strands are upside down mirror images of one another!

9. (Yes You Need To Draw This…)