Cell Death Flashcards
What is programmed cell death commonly called?
Apoptosis
Apoptosis is a tightly regulated process where cells actively participate in their own death.
What does the term ‘apoptosis’ derive from?
Ancient Greek, meaning the ‘falling of petals from a flower’ or ‘of leaves from a tree in autumn’
he term was first used in a classic paper by Kerr et al in 1972.
What is the role of apoptosis in embryonic development?
Helps in digit formation and is a normal event in the development of the nervous system
Lack of apoptosis can lead to conditions like syndactyly.
List three functions of apoptosis in adult organisms.
Normal cell turnover
Tissue homeostasis
Elimination of activated, damaged, and abnormal cells
How does apoptosis contribute to liver size regulation?
Balances cell death with cell division to maintain liver size after injury or stimulation
For example, liver cell proliferation increases after part of the liver is removed.
What is the primary difference between apoptosis and necrosis?
Apoptosis is programmed cell death, while necrosis is accidental cell death
Apoptosis is a physiological process, whereas necrosis is pathological.
Describe two morphological features of necrotic cells.
Volume enlargement
Loss of membrane integrity
Describe two morphological features of apoptotic cells.
Volume reduction
Formation of apoptotic bodies
What is the energy requirement for apoptosis?
Energy (ATP)-dependent
Apoptosis is an active process that does not occur at low temperatures.
What are caspases?
A family of intracellular proteases that play a pivotal role in apoptosis
They exist as inactive precursors called procaspases.
What initiates the activation of caspases?
Extracellular or intracellular death signals
These signals lead to the aggregation of adaptor molecules that activate procaspases.
What are the two main pathways of apoptosis?
Extrinsic pathway (death receptor-mediated events)
Intrinsic pathway (mitochondria-mediated events)
What can excessive apoptosis lead to?
Neurodegenerative and immunodeficiency disorders Examples include AIDS and ischemia.
What can decreased apoptosis lead to?
Cancer and autoimmune disorders
in the blank: The extrinsic pathway in apoptosis is mediated by _______ , while the intrinsic pathway is mediated by _______ injury.
death receptors], [mitochondrial
What are the observable characteristics of apoptosis?
•Overall shrinkage of the cell and nucleus
• Loss of adhesion to neighboring cells
• Formation of blebs on the cell surface
• DNA fragmentation
• Rapid engulfment by phagocytosis
