Final answer:
A segment of a chromosome that codes for a protein or part of a protein is called a gene, which functions as the blueprint for making specific polypeptide chains in proteins.
Step-by-step explanation:
A segment of a chromosome that codes for a protein or part of a protein is called a gene. A gene is responsible for the formation of a specific polypeptide chain, which is an essential component of proteins. The genetic code comprises a series of three-letter codes known as codons, each of which corresponds to one amino acid in a polypeptide chain. There are different types of genes, such as structural genes, which specify the final protein or RNA product, and regulatory genes, which control the expression levels of structural genes.
The central dogma of molecular biology illustrates the process by which genes are transcribed into mRNA and then translated into the amino acid sequence of a protein. This is a fundamental aspect of how traits and characteristics are inherited at a molecular level. The DNA within chromosomes carries these genes, which provide the necessary instructions for synthesizing all the diverse proteins required by an organism.