Summary
Programmed cell death carried out by caspase enzymes, removing damaged or unneeded cells without inflammation.
In depth
Apoptosis can be triggered by internal signals (intrinsic pathway via mitochondria, cytochrome c and the apoptosome) or external death ligands (extrinsic pathway, such as Fas). Initiator caspases activate executioner caspases, which cleave cellular proteins. The cell shrinks, blebs and is engulfed by phagocytes.
Unlike necrosis, which is accidental and causes inflammation, apoptosis is tidy and controlled. Bcl-2 family proteins decide whether a cell commits.
Frequently asked questions
What is Apoptosis?
Programmed cell death carried out by caspase enzymes, removing damaged or unneeded cells without inflammation.
Which area of biology covers Apoptosis, and how advanced is it?
Apoptosis is one of the 52 topics in Cell Biology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Autophagy, Receptor Tyrosine Kinases, Cell Signalling.
Can you give an example of Apoptosis?
The webbing between embryonic fingers disappears through apoptosis.
What should I learn before Apoptosis?
Work through the Beginner topics in Cell Biology first, such as Cell Theory, Prokaryotic Cell, Eukaryotic Cell, then return to Apoptosis. Advanced topics assume the Intermediate vocabulary.
What topics are related to Apoptosis?
The closest topics to Apoptosis are Autophagy, Receptor Tyrosine Kinases, Cell Signalling, Facilitated Diffusion. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Apoptosis?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Apoptosis. To practise the whole of Cell Biology, use the Cell Biology quiz.
How is Apoptosis different from Autophagy?
Apoptosis: Programmed cell death carried out by caspase enzymes, removing damaged or unneeded cells without inflammation. Autophagy: A recycling pathway in which cytoplasmic components are enclosed in autophagosomes and degraded by lysosomes. Read both side by side and note what each one explains.
How should I study Apoptosis step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Autophagy and explain the difference aloud. Finally, take the Cell Biology quiz and come back to this page for any question you miss.