- To make these cells (needed by the body), the stem cell grows, and makes more organelles, and then all the chromosomes inside the nucleus are copied. This is by a process called mitosis;
- This is where the chromosomes copy themselves which makes them double stranded. Inside the cell, protein strands (which are attached to each end of the cell) begin to grow, when they are fully grown they pull the double stranded chromosomes apart. The cytoplasm also divides and both are identical. Then the cell begins to split having two different sets of chromosomes to form its own cells. This happens in all the body’s cells apart from the gametes.
- These are the sex cells, sperm and egg; these are made by a process called meiosis.
- This is where all the chromosomes in the testis and ovaries cells make exact copies of all the chromosomes (to begin with a cell in the ovaries/testis has 23 pairs of chromosomes, when it copies them all; it then has 46 pairs, 4 of each chromosome.) Then the cells begin to split into 4. It takes with it 1 of the 4 chromosomes from each set and then it has 1 of each chromosome inside it. It now is a sex cell because it only has 23 single chromosomes not 23 pairs.
- When scientists grow stem cells in a laboratory, they are artificially fertilized and then grown until the scientists can extract the stem cells.
Types of stem cells:
These are the main 3 stem cells that I will be talking about:
- Embryonic stem cells – Come from a 4 – 7 day old embryo. These can form virtually any cells needed by the body in this first period of time.
- Embryonic germ cells – come from a part of a human embryo or foetus that will ultimately produce gametes (the then unformed testis or ovaries).
- Adult stem cells – more specialized than embryonic stem cells. Found in most body tissues and organs. These make mature cell types.
- Stem cells can come from aborted foetuses, and other ways that don’t involve the destruction of the foetuses.
Arguments for:
- Stem cell research is thought to hold good promise for cures of diseases like cancer, Parkinson’s disease, Alzheimer’s disease, genetic and rare immune system disorders and many more.
- Scientists see stem cells as a good way of discovering more about human development, evolution and growth.
- The more time spent on stem cell research, the closer to finding cures scientists get.
- Many more lives will be able to be saved by it (eventually), surely this cannot be a bad thing?
Arguments against:
- When a blastocyst (a laboratory fertilized egg) is destroyed, some believe this to be murder as there are many people who cannot have children naturally, so this life being thrown into the bin is highly unsetting for them.
- Whether or not it may save lives, how many lives have been taken if the above is to be believed?
- Many believe that, embryonic stem cell use is immoral but that adult stem cells should be further researched and more attention paid to it. Yes, this type of stem cell is more specialized but more research should go into seeing whether it can do more in the areas that the embryonic stem cells can do less.
History:
This is only a brief history; I have put in what I feel to be the key development in stem cell research:
- 1960’s – The first presentation of evidence was largely ignored.
- 1968 – Bone marrow transplant successfully treats SCID (an immune system defect).
- 1978 – Haematopoiectic stem cells discovered in human cord blood cells.
- 1981 – Mouse embryonic stem cells are derived from inner cell mass.
- 1997 – Leukemia proved to originate from Haematopoiectic stem cells, first direct evidence/link for cancerous stem cells.
- 2003 – Adult stem cells discovered in primary teeth.
- 2007 – Research shows that skin cells can be ‘re-programmed’ to an embryonic state.
This clearly shows that over the years, research has helped science move forward a lot, and also to improve treatments and medicines for diseases like cancer.
What can be achieved by it?:
- Scientists all over the world are currently researching the many differing uses for stem cells.
- If cells can be ‘re-programmed’ then many diseases that can often cause death because they eat away at cells and the body cannot repair itself, could possibly be cured.
- This may also cause great advancements in the area of vaccinations, for there may be more cures discovered.
- Scientists may also be able to discover what triggers diseases such as breast cancer or retina blastoma cancer (cancer of the eye).
Conclusion:
From my research, I understand that on one hand stem cell research is an amazing advancement in technology. But on the other hand, some may feel that the disposal of the used stem cells is not ethical.
If it’s claims to be so great fall through, then there really isn’t much point of doing the research. But if the research proves to be a success then many cures could be found and in turn many lives saved.
The history of stem cell research shows that the longer we persevere with it, the more positive results will show.
I understand that many differing points of view have to be taken into account whether they are positive or negative. Researchers and scientists must respect other people’s views and try not to offend where possible.
I also see that this could be very difficult to do as there are many people who disagree with it.
I believe that stem cell research is a very good step forward for science but I am uncertain about the derivation of the stem cells used. I feel that further research into Adult stem cells could be highly beneficial to bioscience.
Glossary:
- Adult stem cell – An un-specialized stem cell that is found in tissues that renew themselves.
- Blastocyst – An embryo that is at a very early stage of development and that has been artificially fertilized in a laboratory.
- Cell division – the continuous process by which new cells are made. One dividing to make two, those two each dividing to have a total of four, them dividing to make eight, so on, and so forth.
- Clone – One thing that is in every way identical to its ‘mother’.
- DNA – Deoxyribonucleic acid. The chemical found in the nucleus.
- Embryo – The product of a fertilized egg.
- Embryonic stem cell – Self-renewing and have potential to make any cell needed by the body. Found in the inner cell mass.
- Foetus – The product of a fertilized egg at averagely seven to eight weeks through pregnancy.
- Haematopoiectic cell – Functional cell that makes blood.
- Haematopoiectic stem cell – The parent cell or mature blood cells, found in bone marrow, umbilical cord, cord blood, peripheral blood and in foetal liver.
- In vitro Fertilization (IVF) – Fertilization being achieved outside they body and then implanted into the womb.
- Stem cell – An un-specialized stem cell that has the ability to ultimately divide into any cell.
Bibliography:
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21st century science text books
- The Mail newspaper
- The ITV news
