Which organic compound is most abundant on Earth?

Cellulose is the most abundant organic compound on Earth due to its predominant role in the structure of plant cell walls. It is a polysaccharide composed of long chains of glucose molecules linked together by β(1→4) glycosidic bonds. This structural integrity supports plant cells, providing rigidity and strength, which is essential for the growth and stability of terrestrial plants.

The vast majority of the Earth's biomass is comprised of plants, and since cellulose constitutes a significant portion of plant matter, its abundance is directly linked to the vast number of green plants available in various ecosystems. In fact, cellulose is a major component of wood and contributes significantly to the biomass of terrestrial organisms, making it the most prevalent organic molecule in the biosphere.

In contrast, starch and proteins, while important organic compounds, do not match cellulose in terms of overall abundance. Starch serves primarily as an energy storage molecule in plants and is more limited in its occurrence compared to the structural role of cellulose. Proteins, essential for various biological functions, are present in varied amounts depending mainly on the organism's needs and metabolic processes, and thus they are not as abundant overall as cellulose. Lignin, which provides additional structural support to vascular plants, also plays a role in biomass