Final answer:
Pathogens are internalized by cells through phagocytosis, becoming enclosed in a phagosome that fuses with a lysosome to form a phagolysosome. The path to lysosomes is regulated by the cell's endomembrane system, directing vesicles to lysosomes where hydrolytic enzymes destroy the pathogens.
Step-by-step explanation:
To understand how pathogen-containing vesicles choose their path to lysosomes, we need to look at the cellular processes involved. Once a pathogen such as a bacterium is internalized by a process known as phagocytosis, it becomes enclosed within a vesicle called a phagosome. The phagosome then fuses with a lysosome, forming a phagolysosome. The lysosome contains hydrolytic enzymes that digest and ultimately destroy the pathogen.
Furthermore, vesicles such as endocytotic vesicles that carry the pathogen share common structural features with the plasma membrane. They result from the invagination of a section of the plasma membrane, which encloses the pathogen, pinches off, and ultimately fuses with a lysosome. The hydrolytic enzymes present in lysosomes are crucial for breaking down biological materials, including the intracellular debris and pathogens.
In immune cells like macrophages and dendritic cells, this fusion process is essential for the breakdown of pathogens into peptides for antigen processing and presentation to T cells, a critical step in the immune response. The selection of the lysosomal pathway is regulated by the cell's endomembrane system, ensuring that the vesicles containing pathogens or damaged organelles are targeted to lysosomes for degradation.