apoptosis
Học thuậtThân thiện
Definition
Noun: A process of programmed cell death that occurs in multicellular organisms. It is a highly regulated and controlled mechanism where a cell activates an internal program to self-destruct in a way that does not harm surrounding cells. This process is crucial for normal development, maintaining tissue homeostasis, and eliminating potentially harmful cells.
Usage and Examples
- In Developmental Biology: Apoptosis is essential for shaping tissues and organs during embryonic development.
- Example: The removal of the webbing between human fingers during fetal development occurs through apoptosis.
- In Immune System Function: It is used to eliminate old, unnecessary, or potentially dangerous cells, such as virus-infected cells or cells with DNA damage.
- Example: The body uses apoptosis to remove immune cells that could mistakenly attack the body's own tissues.
- In Disease Context: Dysregulation of apoptosis can contribute to diseases; too little can lead to cancer, while too much can lead to neurodegenerative disorders.
- Example: Researchers are studying how to induce apoptosis in tumor cells as a potential cancer therapy.
Advanced Usage and Concepts
- Biochemical Pathway: Apoptosis involves a cascade of biochemical events, including the activation of enzymes called caspases, which break down cellular components.
- Morphological Changes: A cell undergoing apoptosis exhibits characteristic changes, such as cell shrinkage, chromatin condensation, and fragmentation into membrane-bound "apoptotic bodies" that are phagocytosed by other cells.
Variants and Related Words
- Apoptotic (Adjective): Relating to or involving apoptosis.
- Example: The scientist observed the apoptotic cells under the microscope.
- Programmed Cell Death (PCD): A broader term that often includes apoptosis as its most common form.
- Necrosis: A form of traumatic, unprogrammed cell death caused by external factors like injury or toxins, which often triggers inflammation, unlike apoptosis.
Synonyms
- Programmed cell death
- Cell suicide
Related Phrases and Idioms
- To undergo apoptosis: The standard phrase describing a cell entering this process.
- Example: When severely damaged, a healthy cell will undergo apoptosis.
- To trigger/induce apoptosis: To initiate the process.
- Example: Certain chemotherapy drugs work by triggering apoptosis in cancer cells.
- To inhibit/block apoptosis: To prevent the process from occurring.
- Example: Some viruses produce proteins that inhibit apoptosis to survive inside the host cell.
Noun
- a type of cell death in which the cell uses specialized cellular machinery to kill itself; a cell suicide mechanism that enables metazoans to control cell number and eliminate cells that threaten the animal's survival