Final answer:
A gene is a segment of DNA that codes for a specific protein. It is capable of synthesizing a specific protein through the process of gene expression.
Step-by-step explanation:
A gene is a segment of DNA that carries the code for a specific polypeptide chain or RNA molecule. It is capable of synthesizing a specific protein. The process of gene expression involves the transcription of DNA into messenger RNA (mRNA), which is then translated into a sequence of amino acids to produce a protein.