From left to right, the structures of A, B and Z DNA

From left to right, the structures of A, B and Z DNA.

Nucleic acids are biopolymers made of nucleotides. A nucleotide consists of a nitrogenous base, a sugar, and one or more phosphate groups. In addition to being the monomer units of DNA and RNA, nucleotides are present in a great many biochemical processes, so in reviewing the nature of nucleic acids, it is good to broaden the focus beyond the chemical properties and structure of DNA and RNA to include the behavior of nucleotides elsewhere in biochemistry. This is a long list including their appearance as activated intermediates in biosynthesis, as the central energy currency of bioenergetics (ATP), as components of many coenzymes (NAD+ and CoA), and as an important mediator in signal transduction (cyclic AMP).

WikiPremed Resources

Nucleic Acids Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Nucleic Acids
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Learning Goals


Understand the structure of a nucleotide. Be able to distinguish deoxyribonucleotides and ribonucleotides.

Be able to characterize purines and pyrimidines and name the five bases, knowing which occur in DNA and RNA.

Be familiar with the general organic mechanism of phosphodiester bond formation in the polymerization of nucleoside triphosphates in DNA and RNA lengthening.

Understand the structure of the DNA as a helix of two complementary antiparallel strands joined by base pairing.

Be familiar at a basic level with how the A-form, B-form, and Z-forms of DNA are distinguished.

Be able to describe the processes of DNA denaturation and renaturation (annealing).

Understand why RNA is less stable under basic conditions than DNA.

In clear, basic terms, demonstrate the ability to describe the building up of the DNA superstructure in eukaryotic chromatin beginning with the formation of nucleosomes.

Understand the varieties of RNA (mRNA, tRNA, rRNA, snRNA and scRNA) in terms of their structural and functional differences.

Recall the important adenosine derivative, 3'-5'-cyclic adenosine monophosphate, cAMP and its importance as a second messenger involved in passing signal transduction events from the cell surface to internal proteins.

Suggested Assignments

Practice terminology for nucleic acids using the question server. Complete the fundamental terms crossword puzzle. Here is the solution to the puzzle.

Read pp. 114-115 in ExamKrackers Chemistry. Perform practice items 65-72 on pp. 116-117 (practice items for carbohydrates, proteins, lipids & nucleic acids).

Read pp. 3-10 in ExamKrackers Biology I. Perform practice items 1-8 on pg. 11 (subject matter for lipids, carbohydrates, and nucleic acids).

Review the web resources for nucleic acids.

Conceptual Vocabulary for Nucleic Acids