Apoptosis and Cell Death Processes

These flashcards cover key concepts and details related to apoptosis and cell death processes, including mechanisms, pathways, and implications in disease.

What is apoptosis?

A type of programmed cell death that is characterized by specific morphological changes in the cell.

What are the key differences between necrosis and programmed cell death (PCD)?

Necrosis is unintended cell death due to trauma or lack of nutrients, leading to cell swelling and inflammation. PCD, including apoptosis, is a regulated process activated by specific signals.

What morphological changes define apoptosis?

Disassembly of the cytoskeleton and nuclear envelope, chromatin condensation, cell shrinkage, and formation of apoptotic bodies.

What role do phagocytes play in apoptosis?

Phagocytes engulf apoptotic bodies and redistribute usable material without triggering an inflammatory response.

How is apoptosis controlled within the cell?

Apoptosis is mediated by caspase proteins, which are activated from precursors called procaspases.

What initiates the activation of procaspases?

Apoptotic signals received by the cell lead to procaspases associating with adaptor proteins to form an activation complex.

What are the two signaling pathways involved in apoptosis?

The extrinsic pathway involving death receptors and the intrinsic pathway involving mitochondrial protein release.

What occurs in the extrinsic pathway of apoptosis?

Extracellular signals bind to death receptors on the cell surface, leading to the activation of initiator caspases.

What is the role of cytochrome c in the intrinsic pathway?

Released from the mitochondrial intermembrane space, cytochrome c helps form an initiator complex that activates caspases.

How does the extrinsic pathway relate to the intrinsic pathway?

The extrinsic pathway can activate the intrinsic pathway by triggering signals that amplify the apoptotic response.

What is the significance of the Bcl2 protein family in apoptosis?

Bcl2 proteins regulate apoptosis by either promoting or inhibiting the process, influencing cell survival and death.

How are mutations linked to cancer in relation to apoptosis?

Mutations that inactivate death receptors or increase anti-apoptotic proteins like Bcl2 can lead to excessive cell survival and cancer development.

What effect do heart attacks have on cell death?

Heart attacks can lead to necrosis and apoptosis, causing many cells to die due to loss of survival factors.

What happens to cells with p53 gene mutations?

Cells with mutated p53 do not induce apoptosis in response to DNA damage, leading to continued proliferation and accumulation of mutations.