Biomolecules are organic compounds in living organisms that are essential for various biological processes. They serve as the fundamental building blocks and machinery of life, performing functions within cells and tissues. These molecules are important for growth, energy storage, structural support, and signaling.
Proteins
Proteins are biomolecules that play diverse roles in living organisms. They are involved in nearly every process within the body, from catalyzing metabolic reactions to providing structural support. The fundamental building blocks of proteins are smaller units called amino acids.
Every amino acid contains a nitrogen-containing amino group (-NH2) and a carboxylic acid group (-COOH). These amino acids link together through peptide bonds, formed between the amino group of one amino acid and the carboxylic acid group of another, creating long chains known as polypeptides.
The unique sequence and arrangement of these nitrogen-containing amino acids dictate a protein’s specific three-dimensional shape, which is directly related to its function. Proteins serve as enzymes that speed up chemical reactions, structural components like collagen in skin and bone, transport molecules such as hemoglobin carrying oxygen, and antibodies that defend against disease.
Nucleic Acids
Nucleic acids are another class of biomolecules that consistently contain nitrogen and are central to genetic information storage and expression. The two primary types are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). These macromolecules are long chains made up of repeating units called nucleotides.
Each nucleotide consists of three main components: a five-carbon sugar, a phosphate group, and a nitrogen-containing base. These nitrogenous bases—adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA, or uracil (U) in RNA—contain the nitrogen within nucleic acids.
DNA carries the genetic blueprint for an organism and provides instructions for protein synthesis. RNA plays various roles in expressing this genetic information, including acting as a messenger (mRNA) to carry instructions from DNA to ribosomes, and as a component of the ribosomes themselves (rRNA) and transfer molecules (tRNA) involved in building proteins.
The Essential Role of Nitrogen
Nitrogen’s unique chemical properties make it indispensable to the structure and function of proteins and nucleic acids. Its ability to form stable bonds with carbon, hydrogen, and oxygen allows for the creation of the diverse molecular architectures seen in these biomolecules. The presence of nitrogen in amino groups and nitrogenous bases is fundamental to their identity and reactivity.
In proteins, the nitrogen in the amino group is important for forming peptide bonds. This nitrogen also participates in hydrogen bonding, which helps stabilize the protein’s folded structures, such as alpha-helices and beta-pleated sheets.
For nucleic acids, the nitrogenous bases are the informational core. Their nitrogen atoms are important for forming the hydrogen bonds that link complementary base pairs (A with T/U, and G with C) across the DNA double helix or within RNA structures. This precise pairing, facilitated by nitrogen, is essential for the accurate storage, replication, and expression of genetic information.