Main Difference – Nucleic Acid vs Amino Acid
Nucleic acid and amino acid are two types of important biomolecules in the cell. The main difference between nucleic acid and amino acid is that nucleic acid is a polymer of nucleotides that store genetic information of a cell whereas amino acid is a monomer that serves as the building blocks of proteins. Two types of nucleic acids can be identified inside the cell: DNA and RNA. DNA is made up of DNA nucleotides whereas RNA is made up of RNA nucleotides. DNA contains genes, which are encoded for the production of a functional protein. During transcription, RNA molecules are synthesized based on the information in DNA. Messenger RNA (mRNA) molecules determine the amino acid sequence of a protein.
Key Areas Covered
1. What is a Nucleic Acid
– Definition, Structure of Molecule, Role inside the Cell
2. What is an Amino Acid
– Definition, Structure of Molecule, Role inside the Cell
3. What are the Similarities Between Nucleic Acid and Amino Acid
– Outline of Common Features
4. What is the Difference Between Nucleic Acid and Amino Acid
– Comparison of Key Differences
Key Terms: Amino Acids, DNA, DNA Replication, Nucleic Acid, Nucleotides, Protein Synthesis, Proteins, RNA
What is a Nucleic Acid
Nucleic acid refers to complex organic molecules such as DNA or RNA, which are made up of many nucleotides linked in a long chain. The main function of DNA is to store genetic information of an organism and transfer the information to the offspring. RNA is synthesized based on the information on DNA. The main function of RNA in the cell is to assist protein synthesis. The structures of DNA and RNA are shown in figure 1.
Figure 1: Structures of DNA and RNA
The nucleic acid is a polymer, and the monomer of nucleic acids is nucleotide. A nucleotide is made up of a pentose sugar, a nitrogenous base, and one, two, or three phosphate groups. Pentose sugar can be either ribose, which is found in RNA, or deoxyribose, which is found in DNA. Adenine (A), guanine (G), cytosine (C), and thymine (T) are the four types of nitrogenous bases found in DNA. In RNA, uracil (U) is found instead of thymine. Alternating sugar and phosphate molecules form the backbone of the nucleic acid. The bond that occurs between a sugar and a phosphate group of another nucleotide is a phosphodiester bond. The order of the nitrogenous bases determines the type of information stored in the molecule.
What is an Amino Acid
An amino acid refers to a simple organic molecule, which contains both carboxyl and amino groups. Generally, twenty different amino acids serve as building blocks of proteins. Both carboxylic and amino groups are attached to the same carbon. Therefore, each amino acid differs from another amino acid by the type of R group attached to the carbon. The chemical properties of the R group determine the properties of amino acids. The structure of a typical amino acid is shown in figure 2.
Figure 2: Structure of an Amino Acid
Twenty amino acids serve as building blocks of proteins. Each amino acid is represented by a codon in the genetic code. During protein synthesis, the mRNA molecule includes the sequence of amino acids in a functional protein. The twenty amino acids are shown in figure 3.
Figure 3: Twenty Amino Acids
In humans, nine amino acids are considered as essential amino acids since they cannot be synthesized by the body. Therefore, these amino acids should be included in the diet. Other amino acids are synthesized inside the body in various biochemical pathways.
Similarities Between Nucleic Acid and Amino Acid
- Both nucleic acid and amino acid are two biomolecules inside the cell.
- Both nucleic acid and amino acid are made up of C, H, O, and N.
- Nucleic acids are related to amino acids in protein synthesis.
Difference Between Nucleic Acid and Amino Acid
Definition
Nucleic Acid: Nucleic acid is a complex organic molecule such as DNA or RNA, made up of many nucleotides linked in a long chain.
Amino Acid: Amino acid is a simple organic molecule, which contains both carboxyl and amino groups.
Polymer/Monomer
Nucleic Acid: Nucleic acid is a polymer.
Amino Acid: Amino acid is a monomer.
Significance
Nucleic Acid: The monomer of a nucleic acid are nucleotides.
Amino Acid: The polymer of amino acids is a protein.
Atoms
Nucleic Acid: Nucleic acids are made up of C, H, O, N, and P.
Amino Acid: Amino acids are made up of C, H, O, N, and S.
Functional Groups
Nucleic Acid: Nucleic acids are made up of pentose sugars, nitrogenous bases and phosphate groups.
Amino Acid: Amino acids contain carboxylic groups and amino groups.
Type of Bond between Monomers
Nucleic Acid: Phosphodiester bonds occur between nucleotides.
Amino Acid: Peptide bonds occur between amino acids.
Types
Nucleic Acid: DNA and RNA are the two types of nucleic acids.
Amino Acid: Proteins are made up of twenty amino acids.
Synthesis
Nucleic Acid: Nucleic acids are synthesized inside the cell by DNA replication and transcription.
Amino Acid: Amino acids are either synthesized or obtained from the diet.
Role
Nucleic Acid: Nucleic acids store genetic information of the cell and are involved in the synthesis of functional proteins.
Amino Acid: Amino acids are used in the translation of mRNA as building blocks of proteins.
Conclusion
Nucleic acid and amino acid are two types of biomolecules in the cell. Nucleic acid is a polymer that stores genetic information. It is also involved in the production of a functional protein. The monomer of nucleic acids is the nucleotide. Amino acid is a monomer that serves as a building block of a protein. The main difference between amino acid and protein is the structure and role of each biomolecule inside the cell.
Reference:
1.“Nucleic acids (Article).” Khan Academy, Available here.
2. Amino Acids, Biology.com, Available here.
Image Courtesy:
1. “Difference DNA RNA-EN” By Difference_DNA_RNA-DE.svg: Sponk (talk)translation: Sponk (talk) – chemical structures of nucleobases by Roland1952 (CC BY-SA 3.0) via Commons Wikimedia
2. “Amino-acid-structure” By Johndoct – Own work (CC BY-SA 4.0) via Commons Wikimedia
3. “Amino acids 2” (CC BY-SA 3.0) via Commons Wikimedia
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