Final answer:
Lysosomes contain digestive enzymes that are crucial for breaking down and recycling various cellular components and materials ingested by the cell.
Step-by-step explanation:
Lysosomes are membrane-bound organelles that contain digestive enzymes. These enzymes are critical for degrading and recycling cellular waste, foreign material, and damaged organelles. Lysosomes are involved in processes such as autophagy and phagocytosis, thus playing a key role in maintaining the cell's internal environment. Notably, they were discovered by Christian de Duve in the 1960s and are an essential part of the eukaryotic cell's endomembrane system.
The direct answer to what lysosomes contain is digestive enzymes. Lysosomes are often likened to the cell's 'garbage disposal', utilizing their internal hydrolytic enzymes to break down proteins, lipids, nucleic acids, and complex carbohydrates into simpler molecules that can be either recycled within the cell or expelled as waste.