Final answer:
The feedback loop referred to is the foundational interaction between proteins and polynucleotides that governs genetic information storage and protein synthesis, forming a central feature in the evolution of complex metabolic systems and life itself.
Step-by-step explanation:
The feedback loop that connects proteins and polynucleotides forms a complex interactive system where proteins and RNA or DNA act to stabilize, regulate, and perpetuate genetic information and protein synthesis. These interactions can be likened to autocatalysis but involve discrete agents forming a cohesive, self-sustaining system essential for life.
Proteins are synthesized from amino acids linked by peptide bonds to form polypeptides, which function as enzymes, structural elements, or regulatory molecules. On the other hand, polynucleotides such as RNA and DNA are formed by linking nucleotides via phosphodiester bonds.
The synthesis of proteins and the interactions between them and the nucleic acids represented the core of the cyclic processes that led to the evolution of metabolic systems. These systems were governed and streamlined by the genetic code, a set of rules that govern the translation of genetic information into functional protein structures.