Which primary feature allows mitochondria to be called the 'powerhouse of the cell'?

Correct option is D

The correct answer is (D) They synthesize energy in the form of ATP.

Explanation:
• Mitochondria are double-membrane-bound cell organelles found in most eukaryotic organisms.
• They are famously known as the 'powerhouse of the cell' because their primary function is cellular respiration, a process that extracts energy from nutrients (like glucose).
• This extracted energy is used to synthesize Adenosine Triphosphate (ATP), which is the biochemical energy currency of the cell. All cellular activities rely on the breaking of ATP bonds to release required energy.

Information Booster:
• Mitochondrial DNA: Mitochondria are unique because they have their own circular DNA and ribosomes, meaning they can semi-autonomously produce some of their own proteins and divide independently of the cell.
• Endosymbiotic Theory: It is widely believed that mitochondria evolved from free-living prokaryotes (bacteria) that were engulfed by ancestral eukaryotic cells billions of years ago.

Additional Knowledge:
• Option A (Calcium storage): While the smooth endoplasmic reticulum and mitochondria can store calcium, this is not the reason they are called the powerhouse.
• Option B (Digestive enzymes): Lysosomes contain digestive enzymes (hydrolytic enzymes) and are known as the 'suicide bags' or digestive system of the cell.
• Option C (Protein synthesis): Ribosomes are the sites of protein synthesis, often found floating in the cytoplasm or attached to the rough endoplasmic reticulum.