Amino Acid vs Nucleic Acid
Amino acid and nucleic acid are both essential and are widely occurring molecules in biological systems. DNA and RNA nucleic acids are responsible for controlling all the cellular functions and maintaining life. These two types of compounds are related when they are forming proteins inside cells. DNA generates the protein synthesis message and then RNA is responsible for producing proteins with amino acid combination.
Amino acid is a simple molecule formed with C, H, O, N and may be S. It has the following general structure.
There are about 20 common amino acids. All the amino acids have a –COOH, -NH2 groups and a –H bonded to a carbon. The carbon is a chiral carbon, and alpha amino acids are the most important in the biological world. D-amino acids are not found in proteins and not a part of metabolism of higher organisms. However, several are important in the structure and metabolism of lower forms of life. In addition to common amino acids, there are a number of non protein derived amino acids, many of which are either metabolic intermediates or parts of non protein biomolecules (ornithine, citrulline). The R group differs from amino acid, to amino acid. The simplest amino acid with R group being H is glycine. According to the R group, amino acids can be categorized into aliphatic, aromatic, non polar, polar, positively charged, negatively charged, or polar uncharged, etc. Amino acids present as zwitter ions in the physiological pH 7.4. Amino acids are the building blocks of proteins. When two amino acids join to form a dipeptide, the combination takes place in a -NH2 group of one amino acid with the –COOH group of another amino acid. A water molecule is removed, and the formed bond is known as a peptide bond. Thousands of amino acids can be condensed like these, to form long peptides, which are then folded into make proteins.
Nucleic acids are macro molecules formed by the combination of thousands of nucleotides. They have C, H, N, O and P. There are two types of nucleic acids in biological systems as DNA and RNA. They are the genetic material of an organism and are responsible for passing genetic characteristics from generation to generation. Further, they are important to control and maintain cellular functions. A nucleotide is composed of three units. There is a pentose sugar molecule, a nitrogenous base and the phosphate group. According to the type of pentose sugar molecule, nitrogenous base, the number of phosphate groups and nucleotides differ. For example, in DNA, there is a deoxyribose sugar and in RNA, there is a ribose sugar. There are mainly two groups of nitrogenous bases as pyridines and pyrimidines. Cytosine, thymine, and uracil are examples for pyrimidine bases. Adenine and guanine are the two purine bases. DNA has adenine, Guanine, cytocine, and thymine bases, whereas RNA has A, G, C and uracil (instead of thymine). In DNA and RNA, complimentary bases form hydrogen bonds between them. That is adenine: thiamine/ uracil and guanine: cytocine are complimentary to each other. The phosphates are linked to the –OH group of carbon 5 of the sugar. Nucleic acids have formed by combining nucleotides with phosphodiester bonds removing water molecules.
What is the difference between Amino Acid and Nucleic Acid?
• Amino acids have C, H, O, N and S, whereas nucleic acids have C, H, O, N and P mainly.
• Amino acids are simple compounds, which are the building blocks of proteins. Nucleic acids are macromolecules made from nucleotides.
• There are two types of nucleic acids, but a large number of amino acids.