First of all, there are structural differences. This is reflected in the part of the name that refers to the sugar/carbohydrate. RNA contains ribose, while DNA contains deoxyribose, a similar sugar that contains one fewer oxygen molecule (de...oxy). Another difference is that DNA is double-stranded, while RNA is a single strand. Three of the nitrogenous bases are the same in the two types (adenine, cytosine, and guanine), but DNA contains thymine while RNA contains uracil.
There are also functional differences. DNA is the blueprint for all proteins formed by the cells. mRNA takes the message to the cytoplasm, to rRNA, where tRNA brings the amino acids to string together into polypeptides--in the order that was originally dictated by the DNA
DNA = deoxyribose sugar, double helix and contains thymine
RNA = ribose sugar, single stranded and contains uracil
DNA has deoxyribose where RNA has only ribose, DNAs four bases are adenine, thyamine, cytosine and guanine, where RNA has all but instead of thymine there is uracil. DNA is double stranded meaning that it is made of up two strands and its shape is that of a helix or double helix as it is know. RNA is only a single strand. RNA is actually made from the translation of a DNA strand and is involved directly and the building of proteins based on the DNA footprint found in the nucleus of the cell.