This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Which of these organelles functions as the digestive system of the cell? \nSelect and explain. \nA. Mitochondria, B. Rough endoplasmic reticulum, C. Golgi apparatus, D. Lysosomes', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Lysosomes are spherical vesicles enveloped by a single membrane.\xa0\nLysosomes are regarded as the digestive tract of the cell, since they are actively involved in digestion of cellular substances-namely proteins, lipids, carbohydrates and nucleic acids.\xa0\nLysosomal enzymes are categorized as hydrolases.\nThe lysosomal enzymes are responsible for maintaining the cellular compounds in a dynamic state, by their degradation and recycling.\xa0\nThe degraded products leave the lysosomes usually by diffusion, for reutilization by the cell.\nSometimes, however, certain residual products, rich in lipids and proteins, collectively known as Iipofuscin accumulate in the cell.\xa0\nLipofuscin is the age pigment or wear and tear pigment which has been implicated in aging process.\n\nKey Concept:\nLysosomes are regarded as the digestive tract of the cell, since they are actively involved in digestion of cellular substances-namely proteins, lipids, carbohydrates and nucleic acids.\xa0\nRef: Textbook of Biochemistry, Satyanarayana', 'role': 'assistant'}]