Which statement describes the role of caspases in apoptosis?

Which statement describes the role of caspases in apoptosis?

• A. DNA polymerases replicate DNA.
• B. Proteases that dismantle the cell during mitosis.
• C. Ribozyme molecules degrade RNA.
• D. Activated proteolytic caspases execute the death program.

Answer: (D)

In apoptosis, caspases are activated proteolytic enzymes that carry out the cell’s programmed death. They function in a cascade: initiator caspases respond to death signals and activate executioner caspases, which then cleave many cellular substrates. This coordinated proteolysis dismantles the cell’s structure, fragments DNA, and leads to characteristic changes like cell shrinkage and formation of apoptotic bodies—all of which are neatly disposed of by phagocytes without triggering inflammation. The other statements don’t fit because DNA polymerases replicate DNA, ribozymes are RNA catalysts, and the caspases that execute apoptosis are not the same as proteases used during mitosis.

In apoptosis, caspases are activated proteolytic enzymes that carry out the cell’s programmed death. They function in a cascade: initiator caspases respond to death signals and activate executioner caspases, which then cleave many cellular substrates. This coordinated proteolysis dismantles the cell’s structure, fragments DNA, and leads to characteristic changes like cell shrinkage and formation of apoptotic bodies—all of which are neatly disposed of by phagocytes without triggering inflammation. The other statements don’t fit because DNA polymerases replicate DNA, ribozymes are RNA catalysts, and the caspases that execute apoptosis are not the same as proteases used during mitosis.