Nucleic acid, proteins and enzymes (1).

Nucleic acid consists of nucleotides. Each of nucleotides has three parts: triphosphate, ribose and base. They work as the backbone of nucleic acids, energy carrier (ATP) and signaling transducer (cAMP). There are four different bases so that there are four different nucleotides for DNA and RNA each. However, those four bases are primary types and there exist other types of nucleotides.

Proteins are made of amino acids which are connected by peptide bonds, which are covalent bonds. Based on the polarity of R group on each of them, amino acids are grouped into polar, non-polar, basic and acidic amino acids. Non-polar amino acids are hydrophilic so when they get gathered in a protein, they tend to fold into the internal part of a protein by hydrorepulsion. This property is important for some protein functions such as the transmembrane helix and sheet of protein have to be made up of primarily hydrophilic amino acids so they can stay stable in the phospholipid membrane. Also, this is extremely important for the function of an enzyme.