The number of nucleotides in DNA can vary significantly depending on the organism. For example, humans have approximately 3 billion base pairs in their DNA, which corresponds to about 6 billion nucleotides since each base pair consists of two nucleotides (one from each strand of the double helix).
In simpler terms, DNA is made up of four types of nucleotides, known as adenine (A), thymine (T), cytosine (C), and guanine (G). These nucleotides pair up (A with T and C with G) to form the rungs of the DNA ladder. The sequence and number of these nucleotides are what encode the genetic information for an organism.
Other organisms exhibit much larger or smaller amounts of DNA. For instance, certain plants may have more than 100 billion nucleotides, while simpler organisms like some bacteria might have just a few million nucleotides. So, the total count of nucleotides in DNA truly depends on the specific species.