The two strands of the helix run in opposite directions (1 "up" and 1 "down"). The inner edges of the helices are formed by the nitrogenous bases and they run in pairs. Adenine pairs with thymine with 2 hydrogen bonds and cytosine pairs with guanine with 3 hydrogen bonds (Murray et al, 2007).
DNA is present in the chromosomes of most of the living beings. The human genome approximately has 3 billion base pairs of DNA which are arranged in the 23 pairs of chromosomes. Sequence pieces of DNA form genes which carry vital information. The genetic information is achieved by complementary base pairing. Transmission, transcription and translation are the steps involved in transmission of genetic information. Currently, DNA is used in the field of genetic engineering for the treatment of many diseases (Murray et al, 2007).
RNA or ribonucleic acid is similar to DNA except that it is single stranded and the sugar present in it is ribose sugar. RNA consists of repeating units of nucleotides which are made up of a nitrogenous base, a ribose sugar and a phosphate. The pyramidines are guanine and cytosine and the purines are adenine and uracil. RNA is transcribed from DNA by the enzyme called RNA polymerase. There are basically 2 types of RNA: coding RNAs and non-coding RNAs. Messenger RNA (mRNA) is a coding RNA. There are many non-coding RNAs. ...Show more