What are the components of a cell that determine the characteristics of a living thing?

Genes are the fundamental components of cells that carry the information necessary for the growth, development, and functioning of living organisms. They are segments of DNA that encode instructions for the synthesis of proteins, which play crucial roles in determining an organism's traits and characteristics. The specific sequences of nucleotides within genes influence everything from physical attributes like eye color to metabolic processes and susceptibility to certain diseases.

While proteins, cell membranes, and organelle structures are important for the overall functioning and integrity of a cell, they do not individually define the characteristics of a living thing. Proteins are indeed essential as they perform a vast range of functions within organisms, but they are produced based on the instructions provided by genes. Cell membranes serve as barriers that regulate what enters and exits the cell, contributing to its stability and environment but not inherently determining the organism's traits. Organelle structures, like mitochondria and endoplasmic reticulum, support various cellular functions, yet they are part of the broader cellular machinery that operates based on genetic instructions. Thus, genes remain the crucial elements that define the unique characteristics of a living organism.