Why do white blood cells contain enzymes in their lysosomes?

White blood cells, or leukocytes, play a crucial role in the immune response by identifying and eliminating pathogens such as bacteria and viruses. The enzymes contained in the lysosomes of these cells are specifically designed to digest these engulfed pathogens. When a white blood cell encounters a pathogen, it engulfs it through a process called phagocytosis. This results in the pathogen being enclosed in a vesicle that then fuses with a lysosome. The enzymes within the lysosome break down the pathogen into smaller, less harmful components that can be processed or expelled from the cell.

The presence of these enzymes in lysosomes is essential for the immune function of white blood cells, allowing them to effectively clear infections and maintain overall health. This function is not related to energy production, cell division, or oxygen transport, which are served by different cellular mechanisms and components.