Final answer:
A residual body lysosome containing partially digested materials is formed when a food vacuole fuses with a primary lysosome. Lysosomes play a crucial role in digesting biological materials and are part of the cell's endomembrane system, also aiding the immune system in destroying pathogens.
Step-by-step explanation:
A structure called a residual body lysosome, containing partially digested remnants of organelles and phagocytized organic material, is formed when a food vacuole fuses with a primary lysosome.
Lysosomes are important cellular organelles in animal cells that contain hydrolytic enzymes used to break down different types of biological materials. This includes the digestion of old cell organelles through the autophagy process or the destruction of pathogens such as bacteria through phagocytosis. The term residual body refers to the remains of the lysosomal digestion when a secondary lysosome has completed its breakdown of material.
Role of Lysosomes in Cells
Lysosomes are integral to the endomembrane system of a cell, which includes the plasma membrane, nuclear envelope, endoplasmic reticulum, Golgi apparatus, vesicles, and lysosomes themselves. Their role in the immune system is exemplified in white blood cells like macrophages, where they digest invading pathogens through phagocytosis. By fusing with food vacuoles that contain these pathogens or damaged organelles, they form a larger secondary structure called a residual body, which houses the remaining undigested material and eventually expels it from the cell.