Summary of APOPTOSIS CELULAR

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The video discusses the process of apoptosis, or cell death. This is a type of suicide that can occur in multicellular organisms, and there are various biochemical pathways that can activate it. The process is regulated by proteins in the Bcl2 family, and it leads to the death of the cell.

• 00:00:00 The video discusses apoptosis, which is a cellular process that results in the death of a cell. Apoptosis is a type of suicide that can occur in multicellular organisms. There are various biochemical pathways that can activate the onset of apoptosis, which is basically a external or mediated by receptor pathways. Ultimately, both pathways converge at the stage of execution of apoptosis, a molecular process mediated by enzyme called caspases. One external pathway uses extrinsic signals to induce apoptosis, and some examples of these signals include loss of growth factors, decrease in oxygen levels, and radiation exposure. The intrinsic pathway starts when ligands bind to receptors and cause structural changes in the receptor that consist of the aggregation of three or more molecules of receptor-fase R. These intracellular domains join a protein adaptor called farc and the adaptor subsequently associates with the caspase 8 enzyme. The caspase 8 enzyme undergoes a conformational change and becomes active, leading to apoptosis. The complex formed by receptor-fase R, adaptor-fase F, and caspase 8 is known as the apoptosis signal sequence and it leads to apoptosis execution.
• 00:05:00 The initiation of apoptosis cellular pathway is important because cell signals come from the inside of the cell. The general apoptosis pathway is regulated by members of the family of proteins, Bcl2. These proteins include vih3 and back. The process is such that toxic signals cause the over-regulation of proteins bh3 present in the cell's cytoplasm. These proteins detect these signals and move towards the cell's external membrane. They activate the pro-apoptotic proteins bucks and bach. Once activated, they bind and cause the membrane permeabilization of the cell's external mitochondrial membrane that then permits the release of apoptosis-inducing factors from the cell. Mitochondria will play a major role in this process as they are the main sources of these apoptosis-inducing factors. Both the external pathway and the internal pathway converge at level of activation of the caspase 3. Caspases are proteolytic enzymes that normally reside as inactive precursors within the cell, but are activated through the process of initiation of apoptosis. They lead directly to cell death. The main enzymes executing apoptosis are the caspases 3, 6 and 7. The pro-apoptotic complex, called aportó soma, formed
• 00:10:00 Cell death is a process that occurs when cells die or are injured. Cell death can be caused by trauma or exposure to toxins, and it is an active process that requires energy. In form of ATP, cell death results in a sudden loss of cell regulation, leading to an osmotic explosion and the release of intracellular content. This process leads to the death of nearby cells, as well as the death of the cell itself. It is also common to find new cells developing cell death in areas where necrotic cells are common. This process can also lead to an inflammatory response and a fibrous scar that deforms the affected organ.