Unit 4 Notes: DNA Structure

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

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

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

(Yes You Need To Draw This…)

(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?

(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!

(Yes You Need To Draw This…)