A nucleic acid is a linear polymer of monomers we call nucleotides. Now sometimes when describing nucleic acids, instead of using the word nucleotides, we sometimes use nucleotides. But nucleotides and nucleotides are two different things. So in this lecture we're going to discuss what the nucleotide and nucleotide is and what the difference between these two things things actually is. So let's begin by describing nucleosides. So all a nucleocide is it's this unit.