Honors BiologyName
DatePeriod
Online Activity: Stem Cells
Go to the following website for this activity:
Part 1. Click on “The Nature of Stem Cells”
Click on the arrow tabs to navigate through this narrated slideshow. Make sure your volume is “on” to hear the narration, but you can also click on the “CC” button to have the text shown on screen.
1. Specialized cells that carry out specific functions are called ______cells. In contrast, since a stem cell’s role in the body is not yet determined and it can give rise to multiple cell types (including other stem cells), it is considered ______.
2. The important roles of stem cells begin during our ______development and continue through ______.
3. At fertilization, a special kind of stem cell (in this case, a fertilized egg or zygote) is formed which has the potential to grown into a new ______as well as the ______which nourishes the embryo.
4. All cells remain ______during the first few cell divisions in the newly-formed embryo and each one has the same potential as the fertilized egg. As development continues, the process of differentiation begins, in which instructions or signals gradually ______each cell’s potential.
5. One week after fertilization, the embryo is called a ______and looks like a lopsided hollow ball. The cells around the outside will form the ______. The inner cell mass will form all the cells of the ______.
6. Two weeks after fertilization, we can see the organization of the embryonic cells into ______distinct cell layers as the potential of these cells is limited even further. Different sets of cell types will result from each of the three layers.
7. The ectoderm (outer layer) will form the:______. The mesoderm (middle layer) will form the: ______.
The endoderm (inner layer) will form the:______.
8. Cells will further differentiate as development continues, leading to approximately ______different cell types found in the body. However, even adults still have some stem cells – these are known as adult or ______stem cells and they are important for growth, maintenance and repair.
9. Some stem cells divide only when they receive a specific signal to direct them to do so; others work constantly to ______cells that are lost on a daily basis.
10. Somatic (adult) stem cells are different than embryonic stem cells because, under natural conditions:
11. ______is special in that it contains massive amounts of stem cells.
However, most somatic stem cells in other tissue of the body are found sitting amongst large numbers of ______cells.
12. Name at least 4 other types of tissues in the human body which have been found to contain somatic stem cells:
13. Stem cells give rise to all of our differentiated ______and ______as we grow from fertilized eggs into fully formed human beings. Even into adulthood, stem cells help us to ______and maintain our bodies.
Part 2. Click on “Reversing Cell Differentiation”.
1. Until fairly recently, cell differentiation was seen as ______and ______. Once a cell became specialized, it was referred to as “______”. It was considered locked-in and unable to become any other cell type.
2. Scientists first reported they were able to turn a differentiated cell back into a stem cell in the year ______.
3. The difference between a stem cell and a differentiated cell is shown by the fact that stem cells’ DNA is arranged ______with its genes ready to be used. However, as differentiation begins due to signals which enter the cell, only the genes required for a specialized function remain open and active; genes that will not be needed are ______by wrapping those sections more tightly around histone proteins.
4. iPS cells are” ______stem cells” which are created by the reintroduction of ______(how many?) specific genes back into differentiated cells that made them behave like stem cells. It is thought that these genes may actually unlock the genes that were shut down during ______.
You can skip the sectiondescribing STAP cells.
Part 3. Click on “Stem Cells Quick Reference”.
1.______(also known as adult stem cells): Exist naturally in the body. Blood and bone marrow stem cells are routinely used to treat blood-related diseases. Limited because these stem cells can only become a subset of related cell types. Most types of somatic stem cells are in low abundance and are difficult to isolate and grow in culture. Furthermore, isolation could cause considerable tissue/organ damage.
2. ______(ES or hES): Isolated from anearly embryoand grown in a dish -hES have the potential to become any type of cell in the body. Significant ethical/legal concerns surround the destruction of a human embryo.
3.(iPS): Created artificially in the lab by “reprogramming” certain readily available cell types within a patient. Appear to be able to become any type of cell in the body, though more research is still needed in this area.
4. : a method for creating embryonic stem cells (ES) which are specific to each patient. This process involves somatic cell nuclear transfer in which the nucleus of a cell from a patient is transferred to an egg cell which has had its own nucleus removed. As the cell divides, it forms a blastocyst. The inner cell mass of that blastocyst contains ES cells which contain the patient’s own DNA. Significant ethical/legal concerns surround the creation and destruction of a cloned human embryo.
Part 4. Click on “Stem Cells in Use.”
1. When was the first successful bone marrow transplant?
2. In one form of somatic stem cell therapy, a bone marrow transplant is used to cure ______which is a cancer of the white blood cells (leukocytes).
3. ______: These are blood stem cells that can be found in the bloodstream. These PBSC’s can be used just like bone marrow stem cells to treat leukemia, other cancers and a variety of blood disorders. These are easy to collect from drawn blood but are few in number, making it difficult to collect enough for a transplant.
4. Stem cells from the blood of the ______cord (traditionally a discarded by-product of the birthing process) of a newborn baby has proven useful in treatments similar to the uses of bone marrow stem cells and PBSC’s. These cells have a benefit of being less prone to ______than either bone marrow stem cells or peripheral blood stem cells. This may be due to the fact that these cells have not yet developed the features that the recipient’s immune system can recognize and attack.
Part 5. Click on “Unlocking Stem Cell Potential”.
1. The process of regeneration relies on stem cells and is common in many animals. Give one example of regeneration:
2. Explain why regeneration in humans is described as “limited”.
3. ______medicine is a new field of medicine involving the use of stem cells to heal damaged tissue that cannot repair itself.
4. It can be difficult to isolate and grow stem cells from our tissues once we are past the embryonic stages. Scientists are trying to find ways to ______the cells while they are still in the body to coax them to surpass their natural healing abilities.
5. ______drugs stimulate the growth of neurons in the brain. Scientists would like to develop new drugs that can do activate the healing abilities of stem cells in other types of damaged tissues.
6. Another approach involves giving patients transplants of stem cells that were grown in a ______.
7. Scientists are developing new ways to use somatic stem cells as they build on technology used in bone marrow transplants. Other treatments may instead utilize ______stem cells or ______(induced pluripotent stem cells), both of which can develop into any type of cell in the body.
8. Scientists can grow hES and IPS indefinitely in culture and give them certain ______molecules which can cause them to differentiate into cells of different types which may someday be used for transplants in order to grow new, healthy tissue.
9. Give an example of the technique described in #8 above:
10. Summarize the successful use of stem cell transplant in treating mouse spinal cord injuries.
11. Scientists are using what they have learned by making ______mice to develop a new kind of gene therapy.
12. Doctors create ______(IPS) from cells from a patient with a genetic disorder. Then, the a copy of the functional gene is put into the cells in place of the defective gene. After the cells are differentiated into the proper cell type they can be put back into the patient.
13. The technique described in #12 above to successfully cure ______in mice.
14. Stem cells are helping us learn more about ______. Like stem cells, cancer cells grow rapidly and remain undifferentiated. Some tumors may in fact be stem cells growing out of control. Learning about the regulation of growth and differentiation of stem cells may help with the development of new medications to fight cancer.
15. The possibilities for stem cells seem ______, but we are discovering the actual potential and limitations of these techniques as more research is carried out.
Part 6. Click on “The Stem Cell Debate : Is it Over?”
1. List 2 concerns that cause people to debate the use of stem cells.
a)
b)
2. How has President Obama facilitated future research and utilization of stem cells?
If time permits, check out “Go, Go Stem Cells” for engaging animations of stem cells at work.
1