Stem cells, Differentiation and specialized cells Flashcards
What are stem cells?
Stem Cells: Undifferentiated cells that can indefinitely divide to form specialized cells.
What are the two kinds of stem cells?
There are two types of stem cells: embryonic stem cells and tissue stem cells (also called “adult stem cells”).
In what shape are stem cells usually found?
They tend to occur in clumps that differentiate into different tissue layers, like epithelial, muscle, and nerve tissues.
What is the difference between embryonic stem cells and tissue/adult stem cells?
Embryonic stem (ES) cells are pluripotent, so they can be differentiated into any kind of specialized cell, and they exist in the early embryos (7 days old).
Tissue/Adult stem (AS) cells are multipotent, so they can only differentiate into certain types of cells, and there are small amounts found in babies/throughout their lives.
Ex: Adult stem (AS) cells in bone marrow differentiate into white blood cells, red blood cells, or platelets.
What are some possible sources for embryonic stem (ES) cells?
ES cell lines
Excess embryos from fertility clinics
Therapeutic cloning
Some stem cell lines created ___________ are still dividing today
Some stem cell lines created 13 years ago are still dividing today
What is cell differentiation?
Cell Differentiation: A process by which certain parts of the cell’s DNA (in the chromosomes) are turned off/on to specialize the cell.
What part of the cell directs the process of cell differentiation?
This process is directed by the genetic information inside the cell and passed down to offspring in the eggs/sperm cells.
What commonly successful practice is used to treat diseases like leukemia (bone marrow cancer) that involves killing off the old bone marrow cells and injecting healthy (carefully matched) donor stem cells?
Tissue Stem Cell Transplantation
What is the best case scenario for a patient who has undergone a tissue stem cell transplant to treat leukemia (bone marrow cancer)?
In a successful case, the donor stem cells grow in the sick patient’s bone marrow and eventually produce healthy and cancer-free blood cells on their own.
What does regeneration mean (in the context of the human body), and what are some examples of body parts that can undergo regeneration?
Regeneration is the ability of a tissue to repair itself.
Some cells, like skin/muscle cells and bone, can naturally recover after injury.
What is a part of the body that doesn’t typically regenerate?
Nerves in the central nervous system typically don’t regenerate, and nerves in the peripheral nervous system can regenerate, albeit slowly and often incompletely.
What is Tissue Engineering?
Tissue Engineering: The field of research that deals with regenerating parts of the body that normally don’t regenerate.
How could Tissue Engineering be useful in the medical field?
This would be very useful for treating spinal cord injuries and different types of tissue grafting.
How could Tissue Engineering be useful in the field of pharmaceutical/medical research?
This field could also provide a source of biological models for testing drugs and other potentially dangerous substances.
What is Therapeutic Cloning?
The process of an adult creating their own embryonic stem (ES) cells.
How is the process of therapeutic cloning done?
This is done by removing the nucleus from one of the adult’s cells, putting the nucleus into an egg cell, letting the cell divide to form an embryo, and removing the embryonic stem (ES) cells from the embryo, which destroys the embryo.
The diagram below represents therapeutic cloning
Explain the steps illustrated below:
https://drive.google.com/file/d/1bDLgCfgYsSD9jQ_muAUqLN5ZpCNcHpoG/view?usp=drive_link
- A cell is taken from the person whose cells we want to clone.
- This cell fuses with an egg that has had its nucleus
removed. - The cell divides to form an embryo.
- We remove the cells and grow them in a Petri dish.
- We use the cells to fix the problem the person is facing
(in theory, so far)
Why could therapeutic cloning be useful for humans?
This process could be necessary for curing diseases like lymphoma and leukemia by using embryonic stem (ES) cells, which have shown promise in animal studies.
What are the ethical issues associated with therapeutic cloning?
Harvesting embryonic stem (ES) cells destroys the blastocyst, which has the potential for human life, something that is commonly seen as murder.
How does the United States regulate embryonic stem (ES) cell research?
Stem Cell Lines, Fertility Clinic Embryos, Therapeutic Cloning.
Stem Cell Lines: Allowed (but can’t get public funds to make new ones)
Fertility Clinic Embryos: Not allowed
Therapeutic Cloning: Not with public funds
How does Canada regulate embryonic stem (ES) cell research?
Stem Cell Lines, Fertility Clinic Embryos, Therapeutic Cloning.
tem Cell Lines: Allows research on stem cell lines (but no new ones can be made)
Fertility Clinic Embryos: Allows research to be conducted
Therapeutic Cloning: Conducting research is Illegal
How does Australia regulate embryonic stem (ES) cell research?
Stem Cell Lines, Fertility Clinic Embryos, Therapeutic Cloning.
Stem Cell Lines: Allowed
Fertility Clinic Embryos: Allowed
Therapeutic Cloning: Allowed in only some provinces
How does the United Kingdom regulate embryonic stem (ES) cell research?
Stem Cell Lines, Fertility Clinic Embryos, Therapeutic Cloning.
Stem Cell Lines: Allowed
Fertility Clinic Embryos: Allowed
Therapeutic Cloning: Allowed
What is a specialized cell?
Specialized Cell: A cell that has physical & chemical characteristics that differ from other cells, allowing it to perform specific functions.
Fill in the blank
Some specialized cells have more of ___________ ___________ depending on their function.
Some specialized cells have more of certain organelles depending on their function.
What two kinds of organisms can have specialized cells?
These cells exist in both animal and plant cells.
What are some examples of specialized cells in an organism?
Examples:
Cells that line the trachea contain many Golgi bodies to help in the production of mucus. (Protection and Moisturization)
Muscle cells have a lot of mitochondria since they require a lot of energy. (Mitocondria in fat cells < Mitocontria in muscle cells)
Cells found in a plant leaf are different than those found in the tree trunk because of the different functions (photosynthesis and transporting sap).
What are genes?
Genes: The working subunit of DNA, combining to make up chromosomes.
How does the specialization process continue after mitosis?
After mitosis, one of the daughter cells becomes a specialized cell, and the other remains unspecialized.
What is a consequence of cells/DNA becoming specialized?
Once specialized, DNA/cells stop replicating.
How are specialized cells observed?
Blood samples from the patient are used to prepare a blood smear for examination, the slide is usually prepared with a stain that makes certain cells more visible.
These are used as cell samples and examined by very skilled technicians.
How does a cell become specialized?
a) Cells specialize randomly
b) Certain genes turn on/off
c) Generated through cell division of other specialized cells
d) Through mutations
b) Certain genes turn on/off
