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Oct 31, 2023 · Biochemical events lead to characteristic cell changes ( morphology ) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. There appears to be some variation in the morphology and indeed the biochemistry of these “suicide” pathways.
Apoptosis (from Ancient Greek: ἀπόπτωσις, romanized : apóptōsis, lit. 'falling off') is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. [1] Biochemical events lead to characteristic cell changes ( morphology) and death. [2]
- Why Do Cells Undergo Apoptosis?
- Apoptosis Mechanisms
- Inhibition of Apoptosis
- Regulation of Apoptosis
- Apoptosis Assays
- Apoptosis Significance/ Applications/ Roles
- Examples of Apoptosis
- Apoptosis and Cancer
- Apoptosis in Plants
- References and Sources
Most cells are provided with an in-built mechanism of apoptosis as a part of the cell cycle.This mechanism allows the body to get rid of unnecessary cells or infected cells.Apoptosis is considered a vital part of various processes including normal cell cycle, proper development and functioning of the immune system, embryonic development, and chemical-induced cell death.Apoptosis is a part of development as it is essential in the differentiation of a mass of tissue into various groups.The process of apoptosis is highly complex and sophisticated, involving an energy-dependent series of molecular events. Image Source: CUSABIO. Three different pathways work on different mechanisms to achieve apoptosis. All three of these pathways converge at the same terminal pathway, which results in the sequential degradation of cellular organell...
Inhibition of apoptosis inhibits the cell death signaling pathways, which helps the tumor cells to escape apoptosis.Different groups of proteins act as negative regulators of apoptosis which are categorized as anti-apoptotic factors like IAPs and Bcl-2.IAP (Inhibitor of apoptosis) proteins represent a group of negative regulators of both caspases and cell death.IAP group in humans consists of 8 proteins, all of which have a characteristic BIR (Baculovirus IAP Repeat) domain that binds with the caspases and other proteins involved in apoptosis.Several proteins and genes regulate apoptosis. Specific families of proteins are involved in the regulation of apoptosis in various steps.Among all the factors, IAPs and Bcl-2 are two of the most important proteins involved that decide whether the apoptosis is going to complete or inhibit.The extrinsic pathway of apoptosis is inhibited by a protein called c-FLIP which will bind to FADD and caspase-8, rendering them ineffective.Another mechanism of apoptosis regulation in the extrinsic pathway involves a protein called Toso, which blocks Fas-induced apoptosis in T cells by inhibition of caspase-8 activation.Because the process of apoptosis is regulated tightly at various points, it is possible to evaluate the activity of different proteins involved.It is essential to confirm the mechanism of cell death by two different assays as the process of apoptosis and necrosis might overlap.The first essay detects the initial events of apoptosis, whereas the second identifies the execution or terminal phase.Apoptosis assays have been divided into six different groups, which are:Apoptosis is essential during development where many cells undergo programmed cell death, thus contributing to the formation of various tissues and organs from a single mass of tissue. It can even...The regular removal of old cells from the body enables the body to produce new cells, helping maintain the cell population in the body. The inability to do so might result in dramatic consequences...Apoptosis helps in the removal of redundant and damaged cells from the body. At the same time, cells that are infected with a virus, and the ones that cannot be repaired are removed via apoptosis.Apoptosis is often used by the body’s immune system to check if the newly formed cells are self-destructive or not. If the immune cells are found to be destructive against the body’s cell, these ar...Metamorphosis of the adult frog from tadpole
1. Apoptosis is seen in frogs where many structures are destroyed and reabsorbed while the tadpole frog metamorphoses into an adult form. 2. Tadpoles have gills, tail, and even fins which are removed from the body during its transformation into an adult frog. 3. All of these structures are known to be destroyed by different mechanisms of apoptosis.
The nervous system in humans
1. During the early development of the nervous system in the human embryo, a large number (almost 50%) of cells are removed via apoptosis. 2. The exact reason behind the death of this many neurons is not entirely known. However, it has hypothesized that because the neurons tend to form complex connections, a larger number of cells are produced to ensure the efficiency of the process. 3. As a result of this, a larger number of neurons will be produced, which are removed later to maintain the n...
Sloughing off of endometrium
1. The process of removal of layers of cells in the endometrium of the uterus occurs by apoptosis. 2. The periodic loss of cells in the endometrium and the corpus luteum forms the basis for menstruation, which is an important process in the female reproductive system.
Figure: Mechanisms contributing to the evasion of apoptosis and carcinogenesis. Image Source: Rebecca SY Wong. 1. Cancer is considered a result of several genetic changes in a normal cell, causing it to transform into a malignant one which requires the evasion of cell death as an essential change during the process. 2. In simpler words, for a norma...
Figure: Sites of programmed cell death (PCD) in a Vascular Plant. Image Source: The American Society of Plant Biologists. 1. The process and mechanism of apoptosis in plants have some similarities with the mechanism of programmed cell death in animals. 2. However, some differences arise due to the presence of a cell wall in plants and the lack of a...
Tortora GJ and Derrickson B (2017). Principles of Physiology and Anatomy. Fifteenth Edition. John Wiley & Sons, Inc.Waugh A and Grant A. (2004) Anatomy and Physiology. Ninth Edition. Churchill Livingstone.Sharma S, Kaufmann T, Biswas S. Impact of inhibitor of apoptosis proteins on immune modulation and inflammation. Immunol Cell Biol. 2017;95(3):236-243. doi:10.1038/icb.2016.101Elmore S. (2007). Apoptosis: a review of programmed cell death. Toxicologic pathology, 35(4), 495–516. https://doi.org/10.1080/01926230701320337Jan 4, 2024 · Apoptosis, necroptosis, pyroptosis, and ferroptosis are four forms of regulated cell death in mammalian cells that are controlled by distinctive biochemical pathways and have important physiological functions in development and immunity and pathological contributions to many human diseases including cancer, autoimmune diseases, and organ degenerative diseases.
Aug 23, 2023 · Cell death is a biological process that results in the cessation of cell function and, eventually, cell death 1.Its main function is to maintain tissue homeostasis by removing nonfunctional ...
Programmed cell death ( PCD; sometimes referred to as cellular suicide [1]) is the death of a cell as a result of events inside of a cell, such as apoptosis or autophagy. [2] [3] PCD is carried out in a biological process, which usually confers advantage during an organism's lifecycle. For example, the differentiation of fingers and toes in a ...
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Which biochemical events lead to morphology and death?
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Jun 1, 2004 · The morphology of cells dying by necrosis is fairly diverse. The cell membrane becomes permeable early during the death process (Fig. 1 D ). Organelles may dilate, and ribosomes may dissociate from the endoplasmic reticulum. The nucleus disintegrates late, and in some cases chromatin condensation occurs.
