Final answer:
Genes in DNA provide specific instructions for making proteins that determine cell structure and function. The process involves genes being expressed to create proteins needed by the cell, a concept fundamental to the Central Dogma of molecular biology.
Step-by-step explanation:
Genes within the DNA of an organism's chromosomes function as the instructional blueprints that direct the synthesis of proteins. These proteins, in turn, are vital for maintaining the structure and function of cells. Each gene contains the genetic instructions for creating a specific protein. When a cell needs a particular protein, the corresponding gene is 'turned on' or expressed. This process, central to the Central Dogma of molecular biology, includes transcription of DNA to RNA and translation of RNA into a protein's amino acid chain. Proteins constructed in this way perform various essential roles, from building cell structures to catalyzing biochemical reactions.