Explain the structure of mitochondrion. Why is it known as powerhouse of the cell? (UPSC 2023, 20 Marks, )

माइटोकॉन्ड्रिया की संरचना को समझाइए। इसे कोशिका का पावरहाउस क्यों कहा जाता है? (Explain the structure of mitochondrion. Why is it known as powerhouse of the cell?)