exam 2 Flashcards
Why is maintaining HSCs in culture difficult?
HSCs tend to differentiate spontaneously in culture unlike ESCs.
What is the key difference between ESCs and ASCs in terms of potency?:
ESCs are pluripotent while ASCs are multipotent.
Which type of stem cell is easier to isolate and culture?
ESCs are easier to isolate and culture compared to ASCs.
Why are ASCs harder to use than ESCs?
ASCs are rare and potentially difficult to isolate
What is Type 1 Diabetes (T1D)?
T1D is an autoimmune disorder where the body’s immune system destroys insulin-producing cells in the pancreas.
Insulin
Hormone that regulates blood sugar levels.
What happens when insulin-producing cells are destroyed?
The pancreas fails to produce insulin, causing glucose regulation issues.
What are some potential causes of T1D?
Autoimmune attack on insulin-producing cells, viral infection, or pancreatic injury (less common)
How common is diabetes in the population?
Approximately 1 in 10 people have diabetes.
What are common treatments for T1D?
Insulin replacement therapy via injection, insulin-producing cell transplantation from cadavers.
What is a major drawback of insulin-producing cell transplantation?
Transplantation is only temporary and patients require immunosuppressants.
How can stem cells help treat T1D?
Stem cells can be placed in the liver to secrete insulin into the bloodstream without needing to reach the pancreas.
What is the pancreas’ dual function?
The pancreas acts as both an endocrine gland (secreting hormones into the blood) and an exocrine gland (secreting digestive enzymes into the small intestine).
What are pancreatic islets?
Clusters of endocrine cells scattered throughout the pancreas that regulate blood sugar.
What cells produce insulin?
Beta (β) cells in the pancreatic islets.
How does insulin regulate blood sugar?
Insulin acts as a “key” that allows glucose to enter cells, lowering blood sugar.
What are two strategies to prevent the immune system from attacking transplanted cells?
Immunosuppressants and encapsulation (physical barrier that blocks immune cells but allows insulin secretion).
Why might ESCs be preferred over ASCs in research and therapy?
ESCs are pluripotent and ESCs are straightforward to isolate
What is the process of egg formation called?
Oogenesis (occurs in the ovary)
Where do early cell divisions occur during early human development?
In the oviduct (fallopian tube)
What are the key stages of early development from zygote to blastocyst?
Zygote → Morula → Blastocyst (by Day 5).
How does the egg get released and moved along the fallopian tube?
Follicles literally explode to release the egg and cilia help move the egg along.
At what stage are cells fated to become different tissues?
Blastocyst
What are the two key components of a blastocyst and their roles?
Inner Cell Mass (ICM) - Pluripotent becomes all parts of the embryo; Trophoblast - Multipotent
When is the developing organism called an embryo and when is it called a fetus?
Embryo: Up to 9-10 weeks post-fertilization; Fetus: From 10 weeks until birth.
What is gastrulation?
A physical movement of cells that reorganizes the embryo into three germ layers.
What are the three germ layers and their associated tissues?
Ectoderm:
Nervous system (brain, spinal cord, peripheral nerves)
Skin (epidermis, hair, nails)
Sensory organs (eyes, ears)
Tooth enamel
Pituitary gland
Adrenal medulla
Mesoderm:
Muscular system (skeletal, cardiac, and smooth muscle)
Skeletal system (bones, cartilage)
Circulatory system (heart, blood vessels, blood cells)
Excretory system (kidneys, ureters)
Reproductive system (gonads)
Connective tissue (tendons, ligaments)
Dermis of the skin
Endoderm:
Digestive system (lining of the stomach, intestines, liver, and pancreas)
Respiratory system (lining of the lungs and trachea)
Endocrine glands (thyroid, parathyroid)
Urinary bladder
Liver
Pancreas
When do most miscarriages occur?
During gastrulation, often before most people know they are pregnant.
How does cell potency change as cells differentiate?
As cells differentiate, they lose potency.
What drives cell differentiation?
Gene expression changes triggered by environmental signals. Epigenetic changes that alter chromatin structure (without changing DNA sequence).
What alternative method can preserve embryos for future use?
Cryopreservation (freezing).
What is a feeder layer and why is it important?
A layer of irradiated mouse fibroblast cells that promotes self-renewal and inhibits differentiation; These fibroblasts are alive but not dividing.
What is the predicted level of telomerase activity in an adult stem cell?
Medium
What is the predicted level of telomerase activity in a terminally differentiated cell?
None
What is the predicted level of telomerase activity in an embryonic stem cell?
High.
What is the predicted level of telomerase activity in a cell from one of Thomson’s colonies?
High
Why do the authors induce teratoma tumors in immunodeficient mice?
To prove pluripotency by demonstrating differentiation into all three germ layers.
What does the Dickey-Wicker Amendment prohibit?
It prohibits federal funding for the creation of new embryonic stem cell lines.
Under which U.S. president was federal funding available for ESC lines created after 2001
Obama.
What are three frameworks for determining the moral status of an embryo?
Embryo as person, potential, or property.
What are two criteria sometimes used to determine when personhood begins?
Genetic criteria - DNA presence defines a person; Embryological criteria - Implantation marks the beginning of personhood.
What are positive and negative controls in an experiment and why are they important?
Positive control: Demonstrates what a successful outcome should look like
Negative control: Demonstrates what a negative outcome should look like; Both ensure the experimental setup is working properly.
HSCs (Hematopoietic Stem Cells)
Stem cells that give rise to blood cells and immune cells.
Where are ESCs (Embryonic Stem Cells) found?
Pluripotent stem cells are derived from the inner cell mass of the blastocyst.
ASCs (Adult Stem Cells)
Multipotent stem cells found in adult tissues that can only differentiate into a limited range of cells.
Pluripotent
The ability of a stem cell to differentiate into all cell types in the body.
Multipotent
The ability of a stem cell to differentiate into a limited range of cells.
Type 1 Diabetes (T1D)
An autoimmune disorder in which the immune system destroys insulin-producing pancreatic beta cells.
Insulin
A hormone produced by the pancreas that regulates blood sugar levels by enabling glucose uptake in cells.
Autoimmune Attack
A condition where the immune system mistakenly attacks the body’s own cells.
Pancreatic Islets (Islets of Langerhans)
Clusters of endocrine cells in the pancreas that regulate blood sugar.
Beta Cells
Insulin-producing cells found in the pancreatic islets.
Immunosuppressants
Drugs that suppress immune system activity often used to prevent organ or cell rejection after transplantation.
Encapsulation
A method of physically protecting transplanted cells from immune attack while still allowing nutrient and hormone exchange.
Oocytes (Eggs)
Female reproductive cells that are large and contain nutrients
Oogenesis
The process of egg cell development that occurs in the ovary.
Sperm Cells
Male reproductive cells that are small and highly motile
Acrosomes
Specialized protein structures on sperm that aid in penetrating the egg.
Zygote
A fertilized egg formed when a sperm cell fuses with an egg cell.
Morula
A solid ball of cells formed from a zygote before developing into a blastocyst.
Blastocyst
A hollow ball of cells formed in early development that contains the inner cell mass (ICM) and the trophoblast.
Inner Cell Mass (ICM)
A group of pluripotent cells in the blastocyst that develop into the embryo.
Trophoblast
Outer cells of the blastocyst that form the placenta and support the embryo.
Gastrulation
A key developmental process in which the embryo’s cells reorganize into three germ layers.
Ectoderm
The outer germ layer that forms the nervous system and skin.
Mesoderm
The middle germ layer that forms muscles and bones
Endoderm
The inner germ layer that forms the digestive system and internal organs like the pancreas.
Gastrula
The embryonic stage during gastrulation when the three germ layers are formed.
Potency
The ability of a stem cell to differentiate into different cell types.
Differentiation
The process by which stem cells specialize into specific cell types.
Gene Expression
The process by which specific genes are activated or deactivated to guide cell differentiation.
Epigenetics
The study of how environmental and molecular changes affect gene expression without altering the DNA sequence.
IVF (In Vitro Fertilization)
A procedure that fertilizes eggs outside the body for implantation in the uterus.
Cryopreservation
A method of freezing embryos or cells for long-term storage.
Feeder Layer
A layer of irradiated cells (e.g. mouse fibroblasts) that provides nutrients and growth signals for ESC culture.
Confluence
A state in which cultured cells fill the entire dish, requiring passaging.
Passaging
The process of transferring cells from a crowded dish to a new dish for continued growth.
Karyotype
A profile of an organism’s complete set of chromosomes used to assess genetic stability.
Teratoma
A tumor containing cell derivatives from all three germ layers used to demonstrate pluripotency.
Telomerase
An enzyme that maintains telomeres, enabling cell division and renewal in ESCs.
Endometrium
The inner lining of the uterus that grows and sheds monthly.
Basal Layer (Basalis)
The base layer of the endometrium that remains intact during menstruation and regenerates the functional layer.
Functional Layer (Functionalis)
The top layer of the endometrium that thickens and sheds during menstruation.
Uterine Glands
Glands in the endometrium that secrete nutrients for potential embryos.
Endometriosis
A condition in which endometrial tissue grows outside the uterus, causing pain and fertility issues.
Blastocyst Grading System
A method to evaluate IVF blastocysts based on cavity expansion and inner cell mass quality
Dickey-Wicker Amendment
A 1995 U.S. law that prohibits federal funding for the destruction of human embryos for research.
Personhood
The concept of when a human embryo or fetus is considered a person with moral status.
Positive Control
An experimental condition that is expected to produce a successful outcome, confirming the experiment’s validity.
Negative Control
An experimental condition that should produce no effect, ensuring false positives are ruled out.
Self-Renewal
The ability of stem cells to divide and maintain their undifferentiated state.
Unspecialization
The characteristic of stem cells to remain undifferentiated.
Endocrine Function (Pancreas)
The role of the pancreas in producing hormones like insulin.
Exocrine Function (Pancreas)
The role of the pancreas in producing digestive enzymes.
qPCR (Quantitative Polymerase Chain Reaction)
A laboratory technique used to measure gene expression levels.
Immunohistochemistry
A technique that uses antibodies to detect specific proteins in tissue samples.
ESC-Derived Beta Cells
Beta cells generated from embryonic stem cells to replace damaged pancreatic cells.
Pagiluca et al. (2014) Positive Control
Primary beta cells isolated from the pancreas that function like healthy beta cells.
Pagiluca et al. (2014) Negative Control
A known differentiation protocol that produces incomplete beta cells.
H9 Cell Line
A well-established ESC line that demonstrated self-renewal for over 8 months in Thomson et al.’s (1998) study.
Geron Corporation
A biotech company that funded Thomson et al.’s ESC research in 1998.
Voltarelli Trial (2007)
A clinical trial using autologous bone marrow transplants to treat Type 1 diabetes patients by rebuilding their immune system.
ESC-Derived Pancreatic Beta Cells
Lab-generated beta cells used in clinical trials to restore insulin production in T1D patients.
Vertex Pharmaceuticals VX-880
A clinical trial that demonstrated successful ESC-derived beta cell transplantation.
Alabama Supreme Court 2024 Ruling
A legal ruling that classified frozen embryos as children, affecting IVF procedures.
ASRM (American Society for Reproductive Medicine)
An organization that advocates for embryo protection while supporting ESC research.
