Final answer:
Cells use genes to synthesize the necessary proteins, with each gene responsible for producing a specific protein. Gene expression determines a cell's phenotype, while the DNA to protein connection presents a 'chicken-or-the-egg' problem, which the concept of an early 'RNA world' helps to possibly resolve.
Step-by-step explanation:
The Genetic Information in Cells
Proteins are fundamental for the myriad functions cells perform, as well as influencing the traits of multicellular organisms. These proteins are synthesized according to the genetic blueprint found in DNA. Each chromosome within a cell contains a long molecule of DNA, which is organized into functional segments known as genes. These genes carry the information necessary to sequence amino acids into proteins.
Gene expression is the process by which the information from a gene is used to construct proteins, and this expression fundamentally determines a cell's structure and function. While each gene codes for a particular protein, not all genes are expressed at the same time; this selective gene expression contributes to a cell's phenotype, which is the observable characteristics of a cell at a given moment under specified conditions.
To address the "chicken-or-the-egg" conundrum regarding whether proteins or DNA came first, the discovery of RNA, specifically in the context of an early "RNA world," suggests a precursor that could both store information and catalyze chemical reactions, potentially solving the dilemma. RNA may have functioned as a primitive genetic material before ancient biochemical pathways evolved to their current sophistication involving separate roles for DNA and proteins.