Human Genome, Stem Cells, & Reparations
Stems Cells are the source of all body tissues. Growth and development of the human body arises from the stem cell and is maintained by it. Although all cells can divide or copy themselves, stem cells are unique because they can replicate and create all other types of cells. This ability of the stem cell to develop into any of the 220 cell types that make up the human body makes it a powerful tool for biological research and medicine. Scientists believe that stem cell research has the potential of leading to previously incurable diseases.
How are Stem Cells Formed?
When a sperm cell fertilizes an egg, a zygote (fertilized egg) is formed. The zygote divides itself almost immediately to form stem cells. These unspecialized stem cells have the ability to replicate (to form other stem cells) and to make all other specialized cells that make up the body tissues such as bone cells, blood cells, muscle, and skin cells. Although stem cells are present in every cell of the body even in an adult, they lose some of their ability to make a wider range of cells with age. Hence, the youngest stem cells, i.e., those found in the embryo are most useful for research and medicinal purposes.
Sources of Stem Cells
Stem Cells can be obtained for research purposes through four different methods.
Fertility Clinics: During fertility treatment, a process known as in-vitro fertilization is used in which eggs removed surgically from a female ovary are fertilized with sperms in a lab for subsequent implant in a woman's uterus. Numerous fertility clinics fuse more than one egg with sperm as a routine -- this is done to try another implant if the first one does not work. There are thousands of such "left-over" embryos in liquid nitrogen freezers in the U.S.A. And elsewhere. These embryos are the most common source for scientific research.
Aborted Fetuses: Aborted fetuses donated by women were first used for developing stem cell culture by researchers and could be another source for embryos.
Cloning: Privately funded research companies, e.g., Advanced Cell Technology of Worcester, Mass., are trying to create cloned human embryos as sources for stem cells for commercial purposes.
Made to Order: Some companies have fertilized eggs specially to create stem cell sources for research purposes. These include the Jones Institute in Virginia, USA.
Out of the 4 sources the "left-over" embryos from the in-vitro fertilization clinics are the most ethically acceptable and widely used source for stem cell research.
Methodology
The methodology for cultivating stem cell lines in the laboratory (usually in vitro fertilization clinics) is briefly described below:
An egg removed surgically from a female ovary is injected with a sperm. A day after its fertilization, the egg splits into a two-celled embryo, which splits into 4 cells the day after and continues to split until, on the 4th or the 5th day, the embryo becomes a multi-celled ball called a blastocyst. At this point the embroyo (blastocyst) is very tiny and its size can be compared to the dot on an "i."
The embryo can then either be implanted into a woman's womb for starting a pregnancy or stored (frozen in liquid nitrogen) for later use; or it can be used for stem cell research. In case the embryo is used for research, the scientists remove stem cells from inside the blastocyst; thus destroying the embryo. The stem cell lines can now be cultivated in the laboratory and can be made to multiply indefinitely. Research scientists are attempting to treat or "coax" the stem cells in developing them into different kinds of cells, such as muscle cells, nerve cells etc.
The Ethical Debate
Because embryos are destroyed when harvested for research, stem cell research has become a controversial issue and become entangled with the abortion debate. The opponents of stem cell research oppose the use of anything for research that is "viable," i.e., able to grow and argue that it is wrong since it destroys human life and. Supporters of the research point out that the frozen embryos kept in the fertility clinics by the thousands would either be eventually discarded or kept frozen indefinitely. They are of the opinion that the cell research holds immense potential for benefiting mankind through development of cures for diseases such as diabetes, Parkinson's and Alzheimer's.
The opponents are in favor of research conducted through "adult" cells, such as the ones derived from bone marrow or umbilical cords instead of embryos. Most researchers, however, are of the opinion that adult cells are not as versatile or flexible as embryonic cells and far less capable of growing into different types of tissues. The development of human embryos specifically for research by a private company has provided further ammunition for the opponents. They argue that a life start at conception and any destroying of the embryo, thereafter, is morally wrong...
Plant Cell and describes the structure & function of each part Parts of a Plant Cell: Cell Wall' Protoplast': is bounded by a Cell Membrane and contains Cytoplasm, which consists of: Vacuoles Organelles (consists of Plastids, Mitochondria, Ribosomes, Golgi Apparatus & Endoplasmic Reticulum) Nucleus Structure and Functions of Each Part Cell Wall: The Cell Wall is composed mainly of Cellulose whose molecules are joined together in fibrils as layers and contains openings to make it permeable. Most
Photosynthesis 1231 Plant Cell and Solar Cell: Similarities and Differences Photosynthesis is that process by which plants harness the solar energy for producing food. These cells help the plants to trap energy from the daylight. This trapped light is converted into other constituents that are then used by the plant to manufacture food. The additional components such as oxygen are released to the atmosphere. After these processes, the light energy is converted
The RHDl gene product appears to be necessary for proper initiation of root hairs, whereas the RHDS, RHD3, and RHD4 gene products are required for normal hair elongation. These results demonstrate that root hair development in Arabidopsis is amenable to genetic dissection and should prove to be a useful model system to study the molecular mechanisms governing cell differentiation in plants.(Schiefelbein & Somerville, 1990, p.235) The genetic analysis of root
Meiosis, Transpiration, Monocots, Dicots, Plant Cell, Angiosperms, Fungi, Algae The Events of Meiosis and the Importance of Prophase 1 Generally, meiosis has two divisions of events. Each constitutes 4 phases of same names but of different division number. They are prophase, metaphase, anaphase, and telophase. From Meiosis of Access Excellence, the events in meiosis can be summarized as the following. Prophase 1 - chromosomes duplicate into a pair of chromatid. Later, exchanging of
Enzymes 1. How does temperature affect enzyme function? Every enzyme demonstrates maximum activity at a particular temperature known as its optimum temperature. Generally, all enzymes are inactivated at temperatures below 10°C and get denatured (lose its three-dimensional protein nature) above its optimum temperature (Seager & Slabaugh 2010). Experiments conclude that enzyme activity increases by almost ten percent coupled to each degree rise in temperature until it reaches its optimum state and declines beyond
Cells are known as the basic units of life. One thing that plant cells and solar cells have in common is that they are very important to humans and living things on earth. One main difference between plant cells and solar cells is how each harnesses solar energy. Plants harness solar energy to use photosynthesis. Solar cells harness solar energy to convert it to electricity. One of the main duties of
Our semester plans gives you unlimited, unrestricted access to our entire library of resources —writing tools, guides, example essays, tutorials, class notes, and more.
Get Started Now