Cell Death

What is a key morphological difference described between a cell dying by apoptosis and one dying by necrosis?

Approximately how many cells are stated to die by apoptosis each second in a healthy adult human?

What are the two major classes of apoptotic caspases that preexist in the cytosol as inactive precursors?

How are initiator caspases, such as caspase-8 and caspase-9, typically activated at the start of apoptosis?

What is the primary function of activated executioner caspases, such as caspase-3, during apoptosis?

The text identifies three main executioner caspases in vertebrates. What are they?

The extrinsic pathway of apoptosis is initiated by extracellular signal proteins binding to what type of cell-surface molecules?

In the Fas-mediated extrinsic pathway, what is the large protein complex that assembles on the cytoplasmic face of the receptor and activates initiator caspase-8?

The intrinsic pathway of apoptosis is also known as the mitochondrial pathway because it depends on the release of what key protein from the mitochondrial intermembrane space into the cytosol?

In the intrinsic pathway, what wheel-like heptameric structure is formed when cytochrome c binds to the adaptor protein Apaf1, leading to the activation of caspase-9?

The apoptosome is a large, wheel-like structure formed from the oligomerization of the adaptor protein Apaf1. How many Apaf1 molecules assemble to form this structure?

What is the primary function of anti-apoptotic Bcl2 family proteins, such as Bcl2 itself and BclxL?

Which two pro-apoptotic Bcl2 family effectors become activated to trigger MOMP by aggregating into oligomers in the mitochondrial outer membrane?

How do BH3-only proteins, the largest subclass of Bcl2 family proteins, promote apoptosis?

When a cell sustains irreparable DNA damage, the tumor suppressor protein p53 can trigger apoptosis by activating the transcription of which two BH3-only proteins?

What is the function of Inhibitors of Apoptosis (IAPs) like the mammalian protein XIAP?

Following MOMP, which two anti-IAP proteins are released from the mitochondria to promote apoptosis by inhibiting XIAP?

Which BH3-only protein provides the link between the extrinsic and intrinsic apoptotic pathways by being cleaved and activated by caspase-8?

How do extracellular survival factors typically prevent apoptosis?

What is described as the most important "eat me" signal displayed on the surface of an apoptotic cell, which is recognized by phagocytic cells?

In apoptotic cells, phosphatidylserine (PS) accumulates on the outer leaflet of the plasma membrane. What two caspase-dependent mechanisms are responsible for this?

Inactivating mutations in the genes for the Fas death receptor or its ligand can lead to what type of disorder?

The Bcl2 gene was first identified in a common human lymphoma where a chromosome translocation causes its excessive production. How does this contribute to cancer development?

The gene for the tumor suppressor protein p53 is mutated in about 50 percent of human cancers. How does the loss of p53 function contribute to malignancy?

Small-molecule drugs called BH3-mimetics, such as venetoclax, have been developed to treat certain cancers. How do these drugs work?

Caspases are proteases that trigger apoptosis. What two amino acids are key to their name and function?

During apoptosis, chromosomal DNA is fragmented. How is the caspase-activated DNase (CAD) released to perform this function?

Death receptors, such as the Fas receptor, are homotrimers that belong to which receptor family?

The protein FLIP can restrain the extrinsic apoptotic pathway. How does it achieve this?

Cytochrome c has a central role in ATP production by oxidative phosphorylation. What is its entirely new function when released into the cytosol?

Anti-apoptotic Bcl2 family proteins like Bcl2 and BclxL prevent MOMP by binding to which domain of active pro-apoptotic effectors like Bak and Bax?

While both Bak and Bax are pro-apoptotic effectors, they differ in their subcellular localization in the absence of an apoptotic signal. What is this difference?

The text describes a mechanism where the survival factor-activated kinase Akt inhibits apoptosis. How does it do this?

In addition to expressing "eat me" signals, what must an apoptotic cell do to ensure it is engulfed by a macrophage?

The gene for the tumor suppressor protein p53 is mutated so that it no longer promotes apoptosis in response to DNA damage in about what percentage of human cancers?

How does apoptosis contribute to the development of hands and feet in a mouse embryo?

Why is the caspase-initiated proteolytic cascade considered irreversible?

Initiator caspases contain a protease domain and what other smaller domain that is crucial for their activation via adaptor proteins?

When an apoptotic signal activates the pro-apoptotic effector Bax, where does it relocate to trigger MOMP?

Besides inhibiting caspases, XIAP has a ubiquitin-ligase domain. What is the function of this domain?

The Fas ligand, which activates the Fas death receptor, belongs to which family of signal proteins?

During apoptosis, a large cell may break up into membrane-enclosed fragments before being engulfed. What are these fragments called?

The caspase recruitment domain (CARD) in Apaf1 and caspase-9 is structurally and functionally related to what domain found in caspase-8 and its adaptor FADD?

The mammalian Bcl2 family of proteins is divided into three structural and functional classes. Which of the following is NOT one of these classes?

Which Bcl2 homology (BH) domain is shared by all three classes of Bcl2 family proteins and mediates direct interactions between them?

Why does the overproduction of nerve cells followed by culling via apoptosis help ensure proper innervation of target tissues during development?

Why does apoptosis normally not cause a damaging inflammatory response?

The cleavage of nuclear lamins by caspase-6 is one of the key events during apoptosis. What is the direct consequence of this event?

What two events are required for the adaptor protein Apaf1 to become active and oligomerize?

The chemical structure of the BH3-mimetic drug venetoclax is designed to bind tightly and specifically to what feature of the Bcl2 protein?