Test
S377 Chapter 14
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Preguntas del test (13)
1Cell death is an essential process in development and tissue homeostasis.
- AVerdadero
- BFalso
2Cells can die by different mechanisms. Regulated cell death can be of several types, including apoptosis, which involves the action of [blank_start]caspases[blank_end], and autophagic cell death, in which [blank_start]lysosomes[blank_end] are involved. Other forms of death have been described. [blank_start]Necrotic[blank_end] cell death is an unregulated response to severe physiological insults.
- Acaspases
- Blysosomes
- CNecrotic
3Dying cells can be identified not only by their appearance under the EM, but also by histochemical and biochemical methods that demonstrate [blank_start]DNA fragmentation[blank_end], membrane [blank_start]disruption[blank_end] and [blank_start]caspase[blank_end] activation.
- ADNA fragmentation
- Bdisruption
- Ccaspase
4[blank_start]Apoptosis[blank_end], or programmed cell death, involves [blank_start]proteins[blank_end] and signalling [blank_start]pathways[blank_end] that are evolutionarily [blank_start]conserved[blank_end] between animals from C. elegans to humans.
In mammals, many [blank_start]homologues[blank_end] of these proteins have been identified, and apoptosis is under complex and tight [blank_start]regulation[blank_end], which varies between different cell types.- AApoptosis
- Bproteins
- Cpathways
- Dconserved
- Ehomologues
- Fregulation
5[blank_start]Caspases[blank_end] exist as [blank_start]zymogens[blank_end], the procaspases, which can be activated by two main routes; an [blank_start]extrinsic[blank_end] pathway, which involves the activation of cell surface [blank_start]death receptors[blank_end], and [blank_start]intrinsic[blank_end] routes, most of which involve the [blank_start]mitochondria[blank_end].
- ACaspases
- Bzymogens
- Cextrinsic
- Ddeath receptors
- Eintrinsic
- Fmitochondria
6Other organelles, in particular the [blank_start]endoplasmic reticulum[blank_end], also play a role in the regulation of cell death via [blank_start]intrinsic[blank_end] pathways.
- Aendoplasmic reticulum
- Bintrinsic
7[blank_start]Caspases[blank_end] are a family of [blank_start]proteases[blank_end] that cleave substrates at aspartate residues.
There are two subfamilies of caspases, one involved predominantly in [blank_start]cell death[blank_end] and the other in cytokine processing.
Inactive caspases (i.e. [blank_start]procaspases[blank_end]) consist of a large and a small subunit and a [blank_start]prodomain[blank_end] of variable length.
- ACaspases
- Bproteases
- Ccell death
- Dprocaspases
- Eprodomain
8Two types of caspase, [blank_start]initiator[blank_end] caspases and effector [blank_start]caspases[blank_end], are involved in cell death. Initiator caspases, when activated, go on to activate [blank_start]effector[blank_end] caspases, which in turn go on to cleave downstream [blank_start]cellular proteins[blank_end].
- Ainitiator
- Bcaspases
- Ceffector
- Dcellular proteins
9Initiator [blank_start]procaspases[blank_end] exist as monomers and possess a [blank_start]long[blank_end] prodomain, which include either [blank_start]CARD[blank_end] or DED domains. They are [blank_start]self-activated[blank_end], a process made possible by assembly into large multimolecular aggregates. This is called [blank_start]scaffold-mediated activation[blank_end] and involves interactions with homologous CARD or [blank_start]DED[blank_end] domains on other proteins.
- Aprocaspases
- Blong
- CCARD
- Dself-activated
- Escaffold-mediated activation
- FDED
10[blank_start]Effector[blank_end] procaspases exist as [blank_start]dimers[blank_end]. They have a [blank_start]short prodomain[blank_end] and are activated upon cleavage by [blank_start]initiator[blank_end] caspases. Activation takes place by cleavage between the [blank_start]subunit domains[blank_end], and removal of the [blank_start]prodomain[blank_end]; activated effector caspases are [blank_start]tetramers[blank_end].
- AEffector
- Bshort prodomain
- Cinitiator
- Dsubunit domains
- Eprodomain
- Ftetramers
- Gdimers
11Certain activated caspases are inhibited by [blank_start]IAPs (Inhibitors of APoptosis)[blank_end], a family of proteins some of which are [blank_start]ubiquitin[blank_end] ligases. IAPs act by binding activated caspases, thereby inactivating them [blank_start]directly[blank_end], and also targeting them for [blank_start]degradation[blank_end] at the [blank_start]proteosome[blank_end]. (They may also act by a mechanism that involves their N-terminal amino acid.)
Caspases may be inhibited by [blank_start]synthetic[blank_end] peptides that have the same sequence of amino acids as that of the cleavage sites of their substrates.- AIAPs (Inhibitors of APoptosis)
- Bubiquitin
- Cdirectly
- Ddegradation
- Eproteosome
- Fsynthetic
12Label the diagram of the extrinsic pathway of apoptosis
- ADeath Domains (DD)
- Bligand binding brings DDs together
- CAdaptor proteins bind
- Ddeath-inducing signalling complex (DISC)
- Einitiator caspase binds
- Finitiator caspase activated
- Geffector caspase activated
- Hin some cells, cleaves Bid
- Itriggers intrinsic pathway
13The [blank_start]extrinsic[blank_end] apoptotic pathway involves activation of [blank_start]cell surface receptors[blank_end] by ligands that may be soluble or on the surface of other cells. The extrinsic pathway is involved in [blank_start]targeted killing[blank_end] and is essential, among other things, for [blank_start]lymphocyte[blank_end] development and regulation of lymphocyte numbers following an [blank_start]immune response[blank_end].
[blank_start]Death receptors[blank_end] (e.g. Fas) on the target cells [blank_start]cluster[blank_end] upon binding of ligand (e.g. Fas ligand). The intracellular part of each death receptor includes a [blank_start]death domain[blank_end] that is also present in [blank_start]adaptor proteins[blank_end], which are hence recruited to the activated receptor to form a complex known as the [blank_start]DISC[blank_end]. The adaptors also possess a [blank_start]death effector domain[blank_end], shared by some [blank_start]initiator procaspases[blank_end] (e.g. procaspase 8). Thus initiator procaspases are recruited to the DISC and this proximity allows their [blank_start]autoactivation[blank_end].
The activated initiator caspases may go on to directly cleave downstream [blank_start]effector caspases[blank_end] (e.g. procaspase 3) or Bid, which stimulates the [blank_start]intrinsic[blank_end] pathway.
Activation of the extrinsic pathway may be inhibited by [blank_start]decoy receptors[blank_end], or decoy adaptors/caspases, which lack [blank_start]functional domains[blank_end].- Aextrinsic
- Bcell surface receptors
- Ctargeted killing
- Dlymphocyte
- Eimmune response
- FDeath receptors
- Gcluster
- Hdeath domain
- Iadaptor proteins
- JDISC
- Kdeath effector domain
- Linitiator procaspases
- Mautoactivation
- Neffector caspases
- Ointrinsic
- Pdecoy receptors
- Qfunctional domains
Información
- Descripción
- Quiz based on summaries of chapter 14
- Autor
- Mikki M
- Idioma
- English
- Visitas
- 35
- Etiquetas
- Valoración
- Aún sin valoraciones Valora este test