A gene is a sequence of DNA or RNA nucleotides that encodes information for the synthesis of a gene product.
Gene expression occurs when the information in the gene is expressed and used to synthesize a gene product. The products are often protein. However, not all genes code for protein, some genes (called non-coding DNA) code for regulators.
Protein is an essential molecule for all living things and is a component of most chemicals of life, including enzymes. It indeed makes life possible.
