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Cell Division and Reproducing New Organisms. Science 9. Regeneration is the ability to regrow a tissue, an organ or a part of the body Humans are only capable of re-growing tissue and skin
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Regeneration is the ability to regrow a tissue, an organ or a part of the body • Humans are only capable of re-growing tissue and skin • Animals with little cell specialization are capable of reproducing an entire organism – this is called fragmentation • As cells become more specialized, the ability to grow “replacement parts” becomes limited Regeneration
The nucleus of every cell in the human body contains a complete code for all your characteristics and all cellular functions • Every cell contains identical DNA • Every cell, however, uses different parts of the DNA because they are directed by different genes • Specialized cells only use parts of their genetic information Specialization and DNA
Skin, bone marrow and other tissues contain stem cells • These cells are capable of continuous dividing and may be able to differentiate into different specialized cells • They may be activated by an injury or disease Stem Cells
Cloning is a natural process • Asexual reproduction is an example of cloning • It is the process of forming identical offspring from a single cell or tissue Cloning
Cells that are capable of reproducing quickly are given hormones to encourage even faster cell division • They then transferred from the area where the hormone is and growth slows down • Cells begin to specialize and the plant begins to form • Delaying specialization appears to be the key in successful plant cloning Cloning Plants
The nucleus is removed from an unfertilized egg cell • A nucleus from an embryo (reproducing cells of a fertilized egg from sperm) is inserted into the egg cell • The cell continues to divide, much like a fertilized egg, and begins to grow into an organism • In order for cloning to work, dividing cells cannot begin to specialize Cloning Animals
Mammalian cells have been successfully cloned • They were only successful when the nucleus used came from a cell that was very early in its division (8 cells) • However, the cloning of a sheep named Dolly changed this • Udder cells were taken from one sheep (Finn Dorset) • Egg was taken from another sheep(Poll Dorset) and its nucleus was removed • The two cells fused and began to reproduce • Cell mass was transferred back into the uterus of another sheep (Blackface) • Clone is born that has the genetic markings of the Finn Dorset Mammals and Cloning