SIGNALLING MOLECULE Meaning and
Definition
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A signalling molecule refers to a chemical compound or substance that is involved in the communication and coordination of various biological processes within an organism. It plays a fundamental role in transmitting information between cells, tissues, and organs, facilitating the regulation and maintenance of physiological functions.
These molecules are typically produced by specialized cells known as signaling cells and are released into the extracellular space. From there, they travel through bodily fluids, such as blood or lymph, or diffuse through intercellular spaces to reach target cells. Signalling molecules interact with specific receptors located on the surface of target cells, initiating a cascade of intracellular events.
Signalling molecules can be classified into various categories based on their structure and mode of action. Hormones, for example, are long-distance signalling molecules that travel through the bloodstream to reach their target cells, exerting widespread effects on various systems. Neurotransmitters, on the other hand, serve as short-distance signalling molecules, transmitting signals between neurons in the nervous system.
These molecules play a crucial role in regulating numerous processes in the body, including growth and development, metabolism, immune response, and cell differentiation. They are responsible for coordinating intricate physiological and behavioral responses, ensuring the proper functioning and homeostasis of an organism. The study of signalling molecules and their pathways is critical in understanding the complexities of biology, enabling scientists to gain insights into disease mechanisms and develop therapeutic interventions.
Etymology of SIGNALLING MOLECULE
The term "signalling molecule" is a compound noun that combines two words: "signalling" and "molecule".
1. Signalling: The word "signalling" is derived from the verb "signal", which originated from the Old French word "signe" meaning "a sign". It entered the English language in the late 16th century. "Signal" refers to an action or gesture that conveys a message or information to someone or something else.
2. Molecule: The word "molecule" comes from the Latin word "molecula", meaning "a small mass". It was first used in the scientific context in the late 18th century and signifies the smallest unit of a chemical compound that retains its chemical properties.
Therefore, "signalling molecule" refers to a substance or compound that carries or conveys information or signals within a biological system.
