Which term is defined as a section of DNA that causes the production of a protein?

• A. Gene
• B. Allele
• C. Chromosome
• D. Genome

Answer: (A)

A gene is a specific sequence of DNA that contains the instructions to make a molecule with a function in the cell, usually a protein. When a gene is expressed, its coding region is transcribed into messenger RNA and then translated to build a polypeptide chain, the protein. Regulatory regions around the gene help control when and where the protein is produced, so expression can vary across tissues or in response to signals. That’s why this term is the one that defines the DNA segment responsible for producing a protein.

In contrast, an allele is a variant form of a gene, a chromosome is a large DNA molecule carrying many genes, and a genome is the entire set of genetic material of an organism.