Building Block Molecules for Biosynthetic Pathways

Anabolic pathways build complex molecules from simpler ones, sourced from both the environment and the products of catabolic pathways.

Biosynthetic pathways are responsible for the synthesis of complex molecules from simpler ones with the help of energy. These building block molecules come from two main sources: the cells' catabolic pathways and the environment. Catabolic pathways break down complex molecules into simpler ones to release energy, while anabolic pathways use this energy to build new complex molecules.

For example, in the process of protein synthesis, amino acids from catabolic pathways are utilized to construct proteins through anabolic pathways. Similarly, nucleic acids obtained from both catabolic pathways and external sources are essential for DNA and RNA synthesis.

Therefore, building block molecules for biosynthetic pathways are derived from the cells' catabolic pathways as well as from the surrounding environment to support the creation of complex molecules required for various biological processes.