Final Biology Essay

8/8/2019 Final Biology Essay

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stem cells is known as potency. Multipotent stem cells can produce cells of a

closely related group while unipotent stem cells can produce just one cell type.

Totipotent cells are produced from the fusion of the egg and the sperm cells.

During the first few divisions, that a fertilized egg undergoes, it produces

totipotent cells. Germ layer is a collection of cells formed during animal

embryogenesis. Pluripotent cells can differentiate into the cells, which are derived

from any of the germ layers. Embryonic stem cells are cell cultures that are

derived from the epiblast tissue of the inner cell mass of a blastocyst, an embryo

that is 4-5 days old. Human embryonic stem cells need the basic fibroblast growth

factor. Embryonic stem cells still remain untested. Adult stem cells, however, can

create a cell like themselves as well as more differentiated cells. Mostly they are

multipotent. Adult stem cells are a natural solution. They naturally exist in our

bodies, and they provide a natural repair mechanism for many tissues of our

bodies.

They belong in the microenvironment of an adult body, while embryonic

stem cells belong in the microenvironment of the early embryo, not in an adult

body, where they tend to cause tumors and immune system reactions. Most

importantly, adult stem cells have already successfully used in human therapies

for many years. As of this moment, no therapies in humans have ever been

successfully carried out using embryonic stem cells. New therapies using adult

type stem cells, on the other hand, are being developed all the time. These cells

have already shown success in treating blood or bone cancers. There are three

germ layers stem cells can be found in: endoderm, mesoderm, and ectoderm.


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Research has shown that stem cells can, not only differentiate into specialized cell

types but they also retain their capacity to regenerate themselves by cell

divisions. Stem cells of the inner cell mass in blastocysts develop into other

tissues of the body. The multipotent stem cells in adults act as the wear and tear

system of the body. Science has not yet been able to conclude the presence of

pluripotent stem cells in adults.

As stem cells can repair damaged tissues, they can be used to cure certain

diseases related to brain or heart damages and the spinal cord. Stem cells have a

potential use in gene therapy as well. Embryonic stem cells are supposed to be of

great use in the treatments for nervous system disorders. Because of the fact

adult stem cells naturally exist in our bodies, they cannot be easily transferred

into young embryos or young developing bodies (children). Not only can adult

stem cells cause problems in embryos and kids but any variation of stem cells can

grow in a different form once in the position originally introduced to that specific

stem cell. This usually results in the growing of excess bone marrow, which could

be extremely hazardous to the people who had stem cells replace their heart

tissue or other vital organ areas. Stem cells require tons of effort to maintain a

stable environment where they can be coaxed into what they need to be

replacing. Most stem cells are pluripotent which gives them the potential to

differentiate between any of the three germ layers. This advantage of

pluripotency means that stem cells can become virtually any of the about 220

cells in our bodies. There is a special division of stem cells called

Hematopoietic Stem Cells. HSC is a stem cell that is isolated from the blood or


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bone marrow that can renew itself, can differentiate to a variety of specialized

cells, can mobilize out of the bone marrow into circulating blood, and can undergo

programmed cell death called apoptosis. These cells are currently more commonly

used for transplants with cancer patients. HSCs are responsible for creating

immune system and blood cells. Stem cells are very diverse, interesting cells,

whos possibilities may only be limited by imagination.

In vitro fertilization is one of the more shady sides of early assisted

reproductive technology. At first IVF was thought of as a joke or more simply,

scientists showing off. Most of the early fears about IVF were that IVF would turn

us into child producing machines. Alas, IVF didnt create legions of less-than-

human children, nor did it destroy the regular family. IVF was simply a new way to

create children through assisted reproduction. There was a frenzy trying to ban

IVF because IVF was a hodgepodge of unregulated activities with absolutely no

support from the public or the government. IVF involves the production of extra

embryos that, eventually, would be unceremoniously destroyed. IVF research

came to somewhat of a compromise with the public by making a rule that

scientists must have a special regard for the potential of human life. Despite

this agreement, the government has never sponsored a single research grant for

IVF, thus making it a private science.

The politicians seemed to have taken charge in the matter of IVF and have

now divided cloning into two categories, therapeutic cloning and reproductive

cloning. Even though the politicians seemed to have taken over, it took nearly

twenty five years to realize that IVF children are at increased medical risk. After


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IVF medical risks were looked into it was revealed that one third of all IVF

pregnancies resulted in twins or triplets, doubling of the miscarriage rate, a

tripling of the rate of still births and neonatal deaths, and a fivefold increase of

ectopic pregnancies. The weights of IVF babies are also more commonly less that

the regular about five and a half pounds. Test-tube babies (IVF babies) are twice

as likely to develop some sort of birth defect or chromosomal or musculoskeletal

differences. Although many problems with IVF came to light the worst of the fears

have been dispelled as myths.

Therapeutic cloning is an excellent way to heal many types of diseases.

Therapeutic cloning starts with the same procedure as is used in adult DNA

cloning. The resultant embryo would be allowed to grow for perhaps 14 days. It's

stem cells would then be extracted and encouraged to grow into a piece of human

tissue or a complete human organ for transplant. The end result would not be a

human being; it would be a replacement organ, or piece of nerve tissue, or

quantity of skin. The first successful therapeutic cloning was accomplished in

2001-NOV by Advanced Cell Technology, a biotech company in Worcester, MA.

If therapeutic cloning using embryos is successful, then perfectly matched,

replacement organs could become freely available to sick and dying people. That

would save countless numbers of lives, and increase the quality of life of

countless others. Three possible examples of therapeutic cloning might include

the use of insulin-secreting cells for diabetes; nerve cells in stroke or Parkinson's

disease; or liver cells to repair a damaged organ. There would probably also be


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side benefits resulting from the research. Further advances in understanding of

how organs regenerate would increase the range of possible treatments that

could be considered. In the United States during 1998, more than 50 disease

advocates and scientific societies, representing such concerns as diabetes,

blindness, Parkinson's disease, glaucoma, AIDS, Down Syndrome, cystic fibrosis,

stroke, lymphoma, infertility and cancer recently sent a letter to the members of

Congress urging them to support federal funding for stem cell research.

Unlike other cloning, therapeutic cloning does not strive to make whole

humans. Instead, it makes embryos as a source of embryonic stem cells for

therapeutic purposes. Because embryonic stem cells can grow into any body of

the body cells, they might be cultured into nerve cells, skin cells, and even hair

follicles for the bald. The obvious use of therapeutic cloning would be treating

deadly diseases like diabetes and Parkinson's where a specific type of cell has

died. It's a good bet that replacing those cells would restore health. Therapeutic

cloning research would end in this country, however, if restrictive legislation

passes the Senate. But society is already willing to tolerate the death of lab-

created embryos during in-vitro fertilization. Therapeutic could be one of the best

new technologies in medicine.

Stem cells have, so far, proven to live up to, and in some cases exceed, our

high standards. These incredible small cells can completely remake the medical

universe. In both the fields of science and medicine, stem cells have struck awe

and wonder into the many healed by their amazing properties.


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