How does the structure of dna enables it to carry information from one generation to the next?

It's a magic code: DNA is a coded instruction. The DNA in bodily cells have the whole set of coded instructions, while DNA in a sperm or an egg contains just half of the coded instructions. When sperm meets egg, they form a whole coded instruction set, half of which came from the Dad's sperm and half from the Mom's egg. The fertilized egg rearranges the DNA so its future sperm or egg will not be like Mom's or Dad's.