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18 Cards in this Set
- Front
- Back
apoptosis is __ __ __
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programmed cell death
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what is the main difference btw apoptosis and necrosis
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apoptosis : cells die in response to a variety of stimuli and they do so in a CONTROLLED REGULATED FASHION
necrosis: UNCONTROLLED CELL DEATH lead to the LYSES of cells |
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necrosis leads to __ __ and __
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lyses of cells
inflammatory response potentially serious health problems |
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a family of proteins known as _____ are typically activated in the early stages of apoptosis
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caspases
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what is the function of caspases
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they breakdown or cleave cellular components that are required for normal cellular function including sturctural proteins in the
cytoskeleton and nuclear proteins such as DNA repair enzymes |
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the caspases can activate degradative enzymes such as ____. what is their function
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DNases cleave DNA in the nucleus
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describe what a cell undergoing apoptosis looks like
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1. cell shrinks after cleavage of lamins and actin filaments in the cytoskeleton
2. the breakdown of chromatin in the nucleus leads to NUCLEAR CONDENSATION (horse shoe like appearance) 3 cells cont to shrink 4 the end stages are often characterized by the apparence of membrane blebs |
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there are a number of mechanisms by which apoptosis can be induced in cells.
it depends on a number of factors such as the expression of PRO AND ANTI APOPTOTIC PROTEINS give two examples of these |
bcl2 proteins and inhibitor of apoptosis proteins
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in some cases the apoptotic stimuli extrinsic signals such as the binding of death inducing ligands to cell surface receptors called ____.
these ligands can either be SOLUBLE or can be expressed on of cells such as ____ |
depth receptors
cytotoxic t lymphocytes |
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t cells recognize damaged or virus infected cells and initiate apoptosis in order to prevent ....
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damaged cells from becoming neoplastic ( cancerous)
or virus infected cells from spreading infection |
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apoptosis can be induced by cytotoxic t lyphocytes using the enzyme _____
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granzyme
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in other cases apoptosis be can initiated following ____ signals that are produced flowing CELLULAR STRESS
cellular stress may occur from what? (3 things) |
intrinsic signals
exposure of radiation or chemical or viral infection or a consequence of a growth factor deprivation or oxidative stress caused by free radicals |
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in general intrinsic signals initiate apoptosis via the involvement of the___
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mitochondria
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the relative ration of ____ can often determine how much cellular stress is necessary to induce apoptosis
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bcl2 proteins
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___ is the premature death of cells and living tissue
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necrosis
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cells that die by necrosis do not usually send the same chemical signals to the immune system that apoptotic cells do. what does this prevent?
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this prevent nearby PHAGOCYTES from locating and engulfing the dead cells leading to the build up of DEAD TISSUE and CELL DEBRIS at or near the site of infection
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what is necrosis caused by? 3 things
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external factors
infections toxins trauma |
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excessive apoptosis causes ____
whereas insufficient amount results in ___ |
hypotrophy,such as ischemic damage
uncontrolled cell proliferation CANCER |