"Unlock the Secrets of Cellular Regeneration: Discover the Power of Stem Cells and Mitosis. Learn how cells divide, differentiate, and renew themselves through the complex process of mitosis, ensuring the transmission of genetic information from mother cell to daughter cells. Explore the potential of adult and embryonic stem cells in cellular therapy, where healthy cells are grafted to repair damaged tissues. Understand the intricacies of DNA replication, cellular differentiation, and the cell cycle, and how these processes impact tissue renewal and regeneration. Dive into the world of cellular biology and uncover the latest insights on cancerous cell mutations and the role of stem cells in maintaining healthy tissues."
Extract
[...] - The replication is said to be semi-conservative: the double helix of each new DNA molecule always contains an old strand and a newly formed strand Cellular differentiation - Process by which cells lose certain abilities and acquire others in relation to their future function within a tissue. For example: erythrocytes: loss of the nucleus and most of their organelles to give them a more adapted shape for oxygen capture (storage of a large number of hemoglobin molecules) - Process composed of 2 stages: ? Stage of proliferation: a large number of identical cells is produced. [...]
[...] Cell cycle Cells: cyclic functioning necessary for proliferation or renewal of the tissue to which they belong. A cycle : - Division of the mother cell into 2 daughter cells - DNA of the mother cell must be copied with maximum reliability during the process of mitosis Each cell is genetically programmed to perform a maximum number of divisions (apoptosis or cellular suicide) A cell can exit the cycle to acquire a specialization related to the tissue to which it belongs = cellular differentiation. [...]
[...] The prophase = individualization of chromosomes o The metaphase = the chromosomes are arranged in the equatorial plane of the cell. ? The anaphase = the chromatids of each chromosome separate ? Each daughter cell will thus receive the same chromosomes as those of the mother cell ? Each chromatid migrates to a pole of the cell and becomes a complete chromosome with a single chromatid ? The telophase = disappearance of chromosomes and appearance of 2 daughter cells. ? [...]
[...] Stage of proper differentiation: the newly created cells transform. - Stem cells main properties: ? Author renewal: they multiply by giving new stem cells. ? Differentiation: they are capable of differentiating to give birth to any type of tissue Present in the embryo, the ftissues, the umbilical cord blood and various tissues of the individual after its birth. Adult stem cells (after birth) have a lesser potential for renewal and differentiation than embryonic stem cells, called 'totipotent' (capable of producing the entire tissue of our organism) Cellular therapy Principle: grafting of healthy stem cells at the level of a damaged tissue, so that they differentiate and can repair the tissue so that it functions normally again. [...]
[...] Cellular differentiation allows for cellular regeneration ? Apoptosis = mechanism leading to the death of cells - Use of stem cells to treat certain diseases = cellular therapy Tumoral process and cancer The tumoral process = the abnormal proliferation of cells leading to the formation of a new autonomous tissue called a tumor Cancer = malignant tumor composed of abnormal cells that escape all control of their division, and which tend to invade neighboring tissues The transition of a normal cell to a cancerous cell is not immediate (several steps and over a long period) Initiation : modification of genetic material of the cell Benign tumor: a long-term process, during which one observes an hyperplasia (proliferation of cells at a slow rate) Transformation: the benign tumor undergoes a dysplasia (abnormal development) in which cells dedifferentiate, divide uncontrollably Invasive Cancer: cancerous cells detach from the tumor and pass through the bloodstream to invade other tissues = formation of secondary tumors or metastases Genetic Modification and Cancer The genes activators of division, or proto-oncogenes, code for growth factors - A mutation transforms them into oncogenes which will excessively stimulate cell proliferation The division-inhibiting genes, or anti-oncogenes code for proteins that prevent cell multiplication - A mutation inactivating its genes, nullifies the control of cell division and causes uncontrolled cell proliferation. [...]
