Cell Bio Ch 18 Flashcards
apoptosis- greek for ______
“falling from”
morphological changes in apoptotic cells
- cells shrink and condense
- cytoskeleton collapses
- nuclear envelope disassembles
- cell surface breaks into apoptotic bodies
- apoptotic bodies are engulfed by neighboring cells or macrophages
- Mitochondrial membrane becomes permeable, allowing release of proapoptotic proteins
apoptosis is_______
programmed cell death
programmed cell death eliminates ______
unwanted cells
2 major pathways for signaling apoptosis
intrinsic pathway- triggered from within the cell by stress or DNA damage
extrinsic pathway- activated when a pro-apoptotic ligand binds to a proapoptic receptor
_________ are intracellular enzymes that trigger cell death.
caspases
Caspases are ____ that have a cysteine at the active site and cleave their target proteins at specific _______
proteases
aspartic acids
Once activated, caspases clave and activate _____
other procaspases, amplifying proteolytic cascade.
procaspases which operate in start of proteolytic cascades are called_____
initiator caspases
when activated, initiator caspases cleave and activate _______ which cleaves targes proteins.
executioner caspases
________ activate the extrinsic pathway of apoptosis
cell-surface death receptors
Death receptors are transmembrane proteins that contain a _______ which is required for receptors to activate apoptosis.
death domain
Death receptors belong to the _______ family of receptors
TNF (tumor necrosis factor)
FADD
fas-associated death domain
DISC
death-inducing signaling complex
killer lymphocytes have _______ attached that activate ________ receptors on the cell surface.
Fas ligand
fas death receptors
intrinsic pathway of apoptosis depends on
mitochondria and the release of mitochondrial proteins
a water soluble component of electron transport chain in mitochondria
cytochrome C
when released into cytosol, cytochrome C binds to ______ activating ________
procaspase
adaptor proteins called Apaf1
Once active, Apaf1 begins to ______
oligomerize to form a wheel hep tamer called “apoptosome”
______ are anti-apoptotic proteins
Bcl2
_______ and ______ are pro-apoptotic proteins
BH123 and BH3
pro-apoptotic BH123 oligomerization causes
the release of cytochrome C from the mitochondria
in the absence of apoptotic signals, anti-apoptotic ______ binds to pro-apoptotic BH123, stopping the release of cytochrome C
Bcl2
pro-apoptotic _____ proteins promote apoptosis by inhibiting anti-apoptotic Bcl2 proteins
BCH3
inefficient apoptosis leads to disease
autoimmune disease and tumors and cancer
autoimmune disease
anti-self lymphocytes are not all killed as they should be in the thymus or spleen
cells with badly damaged DNA that don’t undergo apoptosis can accumulate more mutations, and cause
tumors or cancer
