There are differences between DNA and the three types of RNA that involve location, structure and function. These differences are related to each other.
DNA (deoxyribonucleic acid) is the molecule that stores genetic information; it is "read" by mRNA (messenger ribonucleic acid) in order to help tRNA (transfer RNA) bring the correct amino acids to rRNA (ribosomal RNA) to create proteins.
In eukaryotic organisms, DNA is found in the nucleus. It is double-stranded and its long strands, along with some proteins, make up the chromosomes. DNA uses a different sugar, deoxyribose, as one of its components than RNA (which uses ribose). RNA is single stranded. The other major structural difference between DNA and the different types of RNA is that the four bases utilized in DNA are adenine, cytosine, guanine, and thymine. RNA uses the first three, but instead of thymine uses the base uracil.
As the instructions for assembling proteins are in the nucleus, and the proteins are created in the cytoplasm, the instructions must be sent from the DNA to the cytoplasm; DNA is too large to travel through the nuclear membrane. This is the function of mRNA--it copies a relatively short section of DNA which corresponds to a protein that needs to be made. In the cytoplasm, the mRNA moves to the ribosomes. These are made of rRNA, and are where proteins are assembled. Once the mRNA is positioned on the ribosome, its bases are "read" in batches of three. The 3 base sequence codes for a specific tRNA molecule, which carries the correct amino acid for that code, to attach its amino acid to a growing chain of amino acids. When the amino acid sequence is complete, the finished protein (ie, the chain of amino acids) detaches.
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