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B1 F) Stem Cells
B1 F) Stem Cells
In the first section we looked at a typical eukaryotic cell (plant and animal cell). However, there is no such thing as a typical eukaryotic cell and instead there are hundreds of different types of cells in humans, plants and animals. For example, humans and animals have sperm cells, nerve cells, muscle cells and many more different types of cells. Plants are also made out of many different types of cells, but the cells that they are made up of are different to the cells in humans and animals. Examples of plants cells are root hair cells, xylem cells, phloem cells and many more. The structure of all of these different types of cells relates to their function in a tissue, an organ or organ system (tissue is a group of cells working together to perform a particular function. An organ is a made up of different tissue working together. An organ system is different organs working together). It is important for cells to specialise for their specific roles because by the cells specialising, it allows the cells to carry out their role more effectively, which means that the organism functions more efficiently. Throughout the whole GCSE biology course we will be looking at many different types of cells, and we will see that the different types cells have a structure that best allows them to perform their specific role in tissues, organs or organ systems.
Differentiation is the process where a cell changes to become specialised for the job that it is carrying out. Most human and animal cells differentiate early on in the cell’s life and they are unable to differentiate again to become a different type of cell i.e. if the cell becomes a red blood cell, they will stay being a red blood cell until the end of their life (the red blood cell will be unable to differentiate and become a different type of cell, such as a nerve cell). Many plant cells never lose the ability to differentiate, which means that most plant cells can change the type of cell that they are.
Differentiation is the process where a cell changes to become specialised for the job that it is carrying out. Most human and animal cells differentiate early on in the cell’s life and they are unable to differentiate again to become a different type of cell i.e. if the cell becomes a red blood cell, they will stay being a red blood cell until the end of their life (the red blood cell will be unable to differentiate and become a different type of cell, such as a nerve cell). Many plant cells never lose the ability to differentiate, which means that most plant cells can change the type of cell that they are.
Stem Cells
Stem cells are undifferentiated cells, which means that they can develop into any cell. The cell that the stem cell develops into depends on the instructions that the stem cell is given. Stem cells are found in two places in humans.
One place where stem cells are found is in early human embryos (an unborn offspring). These types of stem cells are known as embryonic stem cells and they have the potential to turn into any type of cell.
Stem cells are also found in adults, but they are only found in certain locations like bone marrow. Bone marrow is found on the inside of some long bones in adults. Stem cells that are found in bone marrow are unable to turn into any type of cell. Instead they can only turn into a few types of cells, such as red and white blood cells.
Stem cells are undifferentiated cells, which means that they can develop into any cell. The cell that the stem cell develops into depends on the instructions that the stem cell is given. Stem cells are found in two places in humans.
One place where stem cells are found is in early human embryos (an unborn offspring). These types of stem cells are known as embryonic stem cells and they have the potential to turn into any type of cell.
Stem cells are also found in adults, but they are only found in certain locations like bone marrow. Bone marrow is found on the inside of some long bones in adults. Stem cells that are found in bone marrow are unable to turn into any type of cell. Instead they can only turn into a few types of cells, such as red and white blood cells.
Meristems
Plants also have stem cells that are grouped together in structures called meristems. Meristems are found in areas of the plant that are growing, which are the tips of shoots and roots. Meristems produce cells that are unspecialised. The cells that meristem produce divide by mitosis and become specialised (they may become xylem and phloem cells or any other type of cells). Also, the cells that are produced by meristem can change what type of cell they are over the course of their life.
Meristems from plants can be produced quickly and cheaply. This means that rare species of plants can be protected from extinction. Furthermore, crops that are resistant to certain diseases can be cloned to produce large quantities of identical plants for farmers that will all be resistant to a disease. This will mean that farmers receive a good crop yield.
Plants also have stem cells that are grouped together in structures called meristems. Meristems are found in areas of the plant that are growing, which are the tips of shoots and roots. Meristems produce cells that are unspecialised. The cells that meristem produce divide by mitosis and become specialised (they may become xylem and phloem cells or any other type of cells). Also, the cells that are produced by meristem can change what type of cell they are over the course of their life.
Meristems from plants can be produced quickly and cheaply. This means that rare species of plants can be protected from extinction. Furthermore, crops that are resistant to certain diseases can be cloned to produce large quantities of identical plants for farmers that will all be resistant to a disease. This will mean that farmers receive a good crop yield.
Applications of Stem Cells
Medical Application
Stem cells are interesting to the medical industry because they have the potential to turn into any type of cell. Stem cells are already used to cure certain diseases like the blood disease sickle cell anaemia. Individual who have sickle cell anaemia produce red cells that have abnormal haemoglobin, which results in the red blood cells becoming a sickle shape. It is an issue in the bone marrow of individuals who suffer from sickle cell anaemia that causes the red blood cells to become sickle shape. Doctors are able to treat individuals who suffer from sickle cell anaemia by doing a bone marrow transplant. During a bone marrow transplant, bone marrow is taken from an individual who does not suffer from sickle cell anaemia and is inserted into someone who does suffer from sickle cell anaemia. If the bone marrow transplant is successful, the patient will be able to produce normal red blood cells that do not turn into a sickle shape, thus curing the patient. However, bone marrow transplants are not always successful because sometimes the individual’s body who is receiving the transplant will reject the transplanted bone marrow.
Furthermore, scientists can extract embryonic stem cells and grow them into a variety of different types of tissue. The grown tissue can be used to replace faulty tissue in the human body. For example, we could grow insulin producing cells for people who suffer from diabetes. We could also grow nerve tissue for people who are paralysed or suffering from nerve degenerative diseases.
We are able to grow stem cells into different types of cells by altering the conditions that the stem cells are grown in. The conditions that the stem cells are put in is a guessing game, but when scientists know what conditions a specific cell will grow in, they are then able to grow that tissue for a transplant or other medical uses (other medical uses include testing new drugs on certain tissue).
Medical Application
Stem cells are interesting to the medical industry because they have the potential to turn into any type of cell. Stem cells are already used to cure certain diseases like the blood disease sickle cell anaemia. Individual who have sickle cell anaemia produce red cells that have abnormal haemoglobin, which results in the red blood cells becoming a sickle shape. It is an issue in the bone marrow of individuals who suffer from sickle cell anaemia that causes the red blood cells to become sickle shape. Doctors are able to treat individuals who suffer from sickle cell anaemia by doing a bone marrow transplant. During a bone marrow transplant, bone marrow is taken from an individual who does not suffer from sickle cell anaemia and is inserted into someone who does suffer from sickle cell anaemia. If the bone marrow transplant is successful, the patient will be able to produce normal red blood cells that do not turn into a sickle shape, thus curing the patient. However, bone marrow transplants are not always successful because sometimes the individual’s body who is receiving the transplant will reject the transplanted bone marrow.
Furthermore, scientists can extract embryonic stem cells and grow them into a variety of different types of tissue. The grown tissue can be used to replace faulty tissue in the human body. For example, we could grow insulin producing cells for people who suffer from diabetes. We could also grow nerve tissue for people who are paralysed or suffering from nerve degenerative diseases.
We are able to grow stem cells into different types of cells by altering the conditions that the stem cells are grown in. The conditions that the stem cells are put in is a guessing game, but when scientists know what conditions a specific cell will grow in, they are then able to grow that tissue for a transplant or other medical uses (other medical uses include testing new drugs on certain tissue).
Therapeutic Cloning
The diagram below show the steps in therapeutic cloning.
The diagram below show the steps in therapeutic cloning.
Therapeutic cloning is where the nucleus of an unfertilised egg is removed. We then removed the nucleus from a cell from the patient and insert this removed nucleus into the unfertilised egg that we have removed the nucleus from – the inserting of the nucleus into the unfertilised egg means that the egg has the same genetic information as the patient. The type of cell that the nucleus is taken from does not matter because the genetic information will be the same in all cells (providing that the cell is a diploid cell). The embryo with the inserted nucleus will start dividing and copying itself. After about 4-5 days, stem cells can be removed. The stem cells can then be grown into the type of cells/ tissue that is required for the patient. The advantage of growing tissue using the patient’s genetic information is that the patient’s body will not reject the tissue because the cells have the same genetic information. This means that the immune system does not attack the cells. However, if the tissue that was being transferred was from someone else, the transferred cells will have different genetic information, which may result in the immune system attacking them, thus causing the tissue/ organ to be rejected.
Issues with Stem Cells
Not everyone is keen on using stem cells. Some religious groups believe that it is immoral to use stem cells. This is because some stem cells are destroyed during the cloning process. Also, some people believe that embryos are alive and that it is ethically wrong to use them in this way. Furthermore, there is a risk of transmitting infections when we are removing cells from individuals and placing new cells/ tissue back into the body. However, the benefits from using stem cells are significant for the reasons outlined earlier. It may be the case that in the exam you are asked to examine the positives and negatives of using stem cells.
Not everyone is keen on using stem cells. Some religious groups believe that it is immoral to use stem cells. This is because some stem cells are destroyed during the cloning process. Also, some people believe that embryos are alive and that it is ethically wrong to use them in this way. Furthermore, there is a risk of transmitting infections when we are removing cells from individuals and placing new cells/ tissue back into the body. However, the benefits from using stem cells are significant for the reasons outlined earlier. It may be the case that in the exam you are asked to examine the positives and negatives of using stem cells.