Re: How many base pairs are there in the human DNA molecule.

The human genome contains 3 billion (3 x 10⁹) base pairs. Because of base pairing, the number of Adenine (A) bases is equal to the number of Thymidine (T) bases; just as the number of Guanine (G) bases is equal to the number of Cytidine (C) bases. However, as higher eukaryotes, humans have what is referred to as a "low G/C content", that is: in humans G+C basepairs account for about 43% of the total DNA, whereas bacterial DNA is over 50% G+C basepairs. Remember also that humans are diploid, that is: each human cell (except for sperm and eggs) contains two copies of the genome, for a grand total of 6,000,000,000 basepairs.