Semantide

A semantide is a molecule whose primary function is to carry information. The term is primarily used in the context of molecular biology, particularly concerning the central dogma. Semantides are distinct from other types of molecules that may participate in biological processes, such as enzymes (which catalyze reactions) or structural proteins (which provide support). The key characteristic of a semantide is that its sequence is crucial for its function. Changes in the sequence directly alter the information it carries.

In the central dogma of molecular biology, DNA, RNA, and protein are considered the primary semantides.

• DNA (Deoxyribonucleic Acid): DNA stores the genetic information of an organism. The sequence of nucleotides (adenine, guanine, cytosine, and thymine) encodes the instructions for building and maintaining the organism.

• RNA (Ribonucleic Acid): RNA serves various roles, including carrying genetic information from DNA to ribosomes (messenger RNA or mRNA) and catalyzing certain reactions (ribozymes). Different types of RNA, such as tRNA and rRNA, also play critical roles in protein synthesis. The sequence of nucleotides (adenine, guanine, cytosine, and uracil) dictates its function.

• Protein: Proteins are the workhorses of the cell, performing a vast array of functions. The sequence of amino acids determines the protein's three-dimensional structure and, consequently, its function. The sequence is encoded by the mRNA.

The concept of semantides helps to clarify the flow of information within a biological system. It emphasizes the informational role of these molecules and distinguishes them from molecules primarily involved in other cellular functions. While the term "semantide" is not universally used, it provides a useful framework for understanding the central role of sequence-dependent information in molecular biology.