DNA:(Deoxyribonucleic acid)
The molecule that store and passes on genetic information from one generation to the next. It is made and resides in the nucleus of living cells. It has a backbone of a sugar molecule called deoxyribose and four nucleotide bases called adenine(A), cytosine(C), guanine(G), and thymine(T). The nucleotides hydrogen bond to another nucleotide base in a strand of DNA opposite to the
original. This bonding is specific, adenine always bonds with thymine (and vice versa) and guanine always bonds with cytosine (and vice versa). This bondin occurs across the molecule creating a double-stranded system.

DNA Replication:
The double stranded DNA molecule has the unique ability that it can make copies of itself. When more DNA is required by an organism (such as during reproduction or cell growth) the hydrogen bonds between the nucleotide bases break and the two single strands of DNA separate. New complemantary bases ( T-A and C-G ) are brought in by the cell and paired up with each of the two separate strands thus forming two new identical, double stranded DNA molecules.
DNA Replication

RNA:(Ribonucleic acid)
A class of nucleic acids similar to DNA but has a uracil base instead of a thymine base. Unlike the double stranded DNA molecule, RNA is a single stranded molecule. It is the main genetic material used in organisms called viruses and important in the production of proteins in other living organisms. RNA can move around the cells of living organisms and thus serves as a sort genetic messenger, relaying the information stored in the cell's DNA out from the nucleus to other parts of the cell where it is used to help make proteins.

During translation, a polypeptide chain specified by the mRNA is synthesized. Each triplet (three base sequence) in the mRNA constitutes as a codon, which specifies one amino acid in the polypeptide chain, or a stop or start signal. Translation requires tRNAs and complex cell machinery, including ribosomes.

During transcription messenger RNA is synthesized as a complementary copy of one of the DNA strands, the transcribed strand. Messenger RNA carries genetic information in the form of sets of three bases called codons, each of which specifies one amino acid. Messenger RNA codons are translated consecutively, thus spacifying the linear sequence of amino acids in the polypeptide chain.
Messenger RNA is synthesized by DNA dependent RNA polymerase enzymes. RNA is formed from nucleotide subunits, each of which contains the sugar ribose, a single base (uracil, adenine, guanine, or cytosine) and three phosphates. RNA polymerase initially binds to aspecial DNA sequence called the promoter region.
As transcription proceeds, incoming nucleotides pair with complementary bases on the transcribed DNA strand. The same base pairing rules are followed as in DNA replication, except that uracil is substituted for thymine.