A nucleic acid is a polymer made up of nucleotides.


Nucleotides are generally made of;

i. Nitrogen-containing base; a molecule which contains a nitrogen atom.

ii. Pentose sugar; meaning contains five carbon atoms in the sugar molecule.

iii. Phosphate Group; usually a phosphorus atom surrounded by a double bonded oxygen atom, single bonded to two oxygen negative ions and an oxygen atom.

A nucleotide.


Since the least complicated molecule is the phosphate group, it can easily be distinguished. However, for now, the distinguishing features for the nitrogen containing base will be the nitrogen atom and for the pentose sugar, the five carbon atoms. If the phosphate group is absent, the sugar-base combination is called a nucleoside.


The most common two forms of nucleotides are Ribonucleic acid (RNA) and Deoxyribonucleic acid (DNA), the molecules responsible for coding the proteins in the cell. (A complex procedure discussed in Chapter 8). The difference between the two is that the pentose sugar in DNA has one oxygen atom less. Also, since these two are the prime nucleic acids we shall be focusing on, their polymer structure is generally helical.


Difference between the DNA and RNA Pentose sugar.


Another popular nucleotide is Adenosine Triphosphate (ATP) which is used as an energy currency in the cell. This will be clearer in later chapters.

Adenosine Triphosphate.

            That is all for this chapter. Next, we begin a new chapter by successively describing every organelle in the cell and their function depending on how their molecules interact, now that you know the basics.