How does the structure of DNA relate to its functions as the hereditary information?

As you may know, DNA is made up of four nucleotide bases. Adenine has thymine stuck to it, and cytosine has guanine stuck to it (they're complementary). This is called the base pairing rule, and is always true, except in the case of RNA, which isn't really relevant here. The order of the pairs in a strand of DNA changes from strand to strand. This order dictates what proteins are produced, and so when DNA in the form of chromosomes are ped down to offspring, the offsprings' cells produce proteins similar to those coded for by his parents' DNA. Segments of a chromosome, by the way, are called genes. You have probably heard the expression, "She's got the best genes," meaning she's inherited the best traits of both parents.