Following are the examples of apoptosis except: September 2008
**Core Concept**
Apoptosis is a form of programmed cell death, a vital process for eliminating unwanted or damaged cells in multicellular organisms. It's a highly regulated process involving a series of cellular and molecular events, including DNA fragmentation, mitochondrial changes, and eventually, cell death.
**Why the Correct Answer is Right**
Apoptosis is characterized by distinct morphological and biochemical features, such as cell shrinkage, chromatin condensation, and DNA fragmentation. The process is mediated by a family of cysteine proteases called caspases, which are activated in a cascade leading to cell death. In contrast, other forms of cell death, such as necrosis, are not characterized by these specific features.
**Why Each Wrong Option is Incorrect**
* **Option A:** Pyroptosis is a form of programmed cell death, but it's distinct from apoptosis in that it's mediated by inflammatory caspases and involves the release of pro-inflammatory cytokines. It's not an example of apoptosis.
* **Option B:** Autophagy is a cellular process involving the breakdown and recycling of damaged organelles and proteins, but it's not a form of programmed cell death like apoptosis. It's a survival mechanism that can be triggered in response to stress.
* **Option C:** Mitosis is the process of cell division that results in the production of two daughter cells with the same number of chromosomes as the parent cell. It's not a form of programmed cell death.
**Clinical Pearl / High-Yield Fact**
Apoptosis is a critical process for maintaining tissue homeostasis and preventing cancer. Dysregulation of apoptosis has been implicated in various diseases, including cancer, autoimmune disorders, and neurodegenerative diseases.
**Correct Answer:** A. Pyroptosis is a form of programmed cell death, but it's distinct from apoptosis.