As you travel through the endoplasmic reticulum look out into the cytoplasm. You will see small round objects called Lysosomes. Lysosomes are filled with enzymes that are used to break up and partially digest food. The food particles are broken up into smaller pieces, which can then be passed on to another organelle called mitochondria. We will learn about the mitochondria shortly.
Another important job that the lysosomes perform is to breakdown and digest older parts of a cell. As a cell ages, parts of it need to be replaced. The lysosomes breakdown the old parts, so that the materials can be reused to build new parts.