Question

The component(s) of the apoptosome is/are

• A. cytochrome c
• B. procaspase 9
• C. caspase 3
• D. caspase 8

Hint:

Cytochrome c triggers the formation of the apoptosome, which contains procaspase 9, leading to the activation of caspases during apoptosis.

Answer 1

The Correct Option is B

Step 1: Understanding the apoptosome.
The apoptosome is a large protein complex involved in the initiation of apoptosis, which is a programmed cell death process. The apoptosome is formed in response to stress or damage signals, and it plays a crucial role in activating caspases that execute the cell death process.
Step 2: Analyzing the options.
- (A) Cytochrome c is released from mitochondria during apoptosis and is a key molecule that triggers the formation of the apoptosome, but it is not itself a component of the apoptosome.
- (B) Correct: Procaspase 9 is a key component of the apoptosome. When cytochrome c binds to apoptotic protease activating factor-1 (Apaf-1), it activates procaspase 9, which then initiates the caspase cascade leading to cell death.
- (C) Caspase 3 is activated downstream of procaspase 9. It is involved in the execution phase of apoptosis but is not a component of the apoptosome.
- (D) Caspase 8 is involved in the extrinsic apoptotic pathway and does not directly participate in the apoptosome formation.
Step 3: Conclusion.
The apoptosome contains procaspase 9 as a major component.
Final Answer: \[ \boxed{\text{Procaspase 9 is a component of the apoptosome.}} \]