Ribosomes serve what main purpose in cells?

Ribosomes are essential cellular structures primarily responsible for synthesizing proteins. They do this by translating messenger RNA (mRNA) into polypeptide chains, which then fold into functional proteins. This process is vital for a multitude of cellular functions, including metabolism, cell structure, and response to external signals.

The role of ribosomes as a "micro-machine" reflects their complex and precise function in assembling amino acids in the order dictated by mRNA, facilitating the formation of proteins according to the genetic code. This means that ribosomes are crucial players in the flow of genetic information within a cell, translating the instructions coded in DNA into functional proteins that carry out various tasks necessary for life.

Other options do describe important cellular functions but do not align with the primary purpose of ribosomes. Storing genetic material is the role of structures like the nucleus, while digesting waste materials is typically the function of lysosomes. Regulating cell division involves various cellular machinery primarily associated with the nucleus and other components of the cell cycle, rather than ribosomes themselves. Thus, the correct answer captures the fundamental role ribosomes play in cellular function.