a nucleotide makes up DNA as the sugar is a close up on the sugar phosphate backbone the nucleotide in the second picture is "3" to "5" prime. "5" to "3" prime is the almost the same thing but upside down in picture 3.picture 4 kinda explains what the nucleotide looks like better don't play attention to 5'c or 3'c yet becuase it may get you confused just observe the and the sugar. when you need draw the full DNA strand with the nucleotides I suggest drawing the circle on top of the sugar. picture 5 is basically the full strand of nucleotides and a close up version of picture 1. ask any questions! :)