Nucleotide: Sugar, Phosphate, Nitrogenous Base
DNA vs. RNA
|Sugar: Deoxyribose||Sugar: Ribose|
|Nitrogenous Bases: A (Adenine), G (Guanine), C (Cytosine), T (Thymine)||Nitrogenous Bases: A (Adenine), G (Guanine), C (Cytosine), U (Uracil)|
|Double-stranded structure (double helix)||Single-stranded structure|
|Genetic Material for Most Organisms||Genetic Material for Some Organisms (like Viruses)|
Adenine and Guanine are Purines. Purines are double-ring structures, and thus they are big.
Cytosine, Uracil and Thymine are Pyrimidines. Pyrimidines are single-ring structures, and thus they are small.
Chargaff's Rule: In order to keep the diameter of the double helix consistent, a purine will always pair with a pyrimidine.
DNA → DNA : A pairs with T and C pairs with G.
DNA → RNA : A pairs with U and C pairs with G. T from DNA pairs with A.
RNA → RNA : A pairs with U and C pairs with G.
(Campbell/Reese. Biology: 6th Ed. Copyright 2002 Pearson Ed. Inc.)