Stem cells
53 flashcards covering Stem cells for the MCAT Biology & Biochemistry section.
Stem cells are special cells in the body that have the unique ability to develop into many different types of cells, such as muscle, blood, or nerve cells. They can also divide and renew themselves, making them essential for growth, repair, and regeneration. There are two main types: embryonic stem cells, which are versatile and can become almost any cell in the body, and adult stem cells, which are more limited but still play key roles in maintaining tissues. This concept is fundamental to understanding human development, disease treatment, and biotechnology.
On the MCAT, stem cells frequently appear in Biology and Biochemistry questions, often as multiple-choice items testing their properties, sources, and applications, such as in regenerative medicine or ethical debates. Common traps include confusing stem cell potency levels—like pluripotent versus multipotent—or overlooking their role in experimental contexts. Focus on key ideas like differentiation mechanisms, ethical implications, and how stem cells are used in research, as questions may involve interpreting data from studies or passages on cell therapy. Remember to practice distinguishing stem cell types from descriptions.
Terms (53)
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Stem cell
A cell that has the ability to divide and create an identical copy of itself as well as differentiate into various specialized cell types, serving as a foundational building block in development and repair.
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Totipotent stem cell
A stem cell that can give rise to all cell types in an organism, including extra-embryonic tissues like the placenta, and is typically found in the earliest stages of embryonic development.
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Pluripotent stem cell
A stem cell capable of differentiating into nearly any cell type of the body but not extra-embryonic tissues, commonly derived from the inner cell mass of a blastocyst or through reprogramming.
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Multipotent stem cell
A stem cell that can differentiate into multiple, but not all, cell types within a specific lineage, such as blood cells from hematopoietic stem cells.
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Unipotent stem cell
A stem cell that can only produce cells of its own type, such as skin stem cells that generate more skin cells, limiting its differentiation potential.
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Embryonic stem cell
A pluripotent stem cell derived from the inner cell mass of a blastocyst, used in research for its ability to form any body cell type, though it raises ethical concerns.
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Adult stem cell
A multipotent or unipotent stem cell found in various tissues of a mature organism, such as bone marrow, which helps maintain and repair the tissue where it resides.
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Induced pluripotent stem cell
An adult cell reprogrammed to a pluripotent state by introducing specific transcription factors, allowing it to differentiate into various cell types for therapeutic applications.
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Hematopoietic stem cell
A multipotent stem cell in the bone marrow that gives rise to all blood cell types, including red blood cells, white blood cells, and platelets, essential for blood production.
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Neural stem cell
A multipotent stem cell in the nervous system that can differentiate into neurons, astrocytes, and oligodendrocytes, playing a key role in brain development and repair.
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Mesenchymal stem cell
A multipotent stem cell found in bone marrow and other tissues that can differentiate into bone, cartilage, fat, and muscle cells, often used in regenerative therapies.
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Self-renewal
The process by which stem cells divide to produce at least one daughter cell that remains a stem cell, maintaining a pool of undifferentiated cells for ongoing tissue maintenance.
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Asymmetric cell division
A division in stem cells where one daughter cell retains stem cell properties and the other differentiates, allowing for both self-renewal and tissue production.
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Symmetric cell division
A division in stem cells that produces two identical daughter cells, either both stem cells or both differentiated, which can expand stem cell numbers during development.
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Cell differentiation
The process by which a stem cell becomes a more specialized cell type through changes in gene expression, guided by signals from the environment.
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Stem cell niche
The specific microenvironment in tissues that supports stem cell maintenance, including surrounding cells and signals that regulate self-renewal and differentiation.
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Epigenetic regulation in stem cells
The modification of gene expression in stem cells through mechanisms like DNA methylation and histone changes, which maintain pluripotency and control differentiation.
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Transcription factors in stem cells
Proteins such as Oct4, Sox2, and Nanog that bind to DNA in stem cells to activate genes for maintaining pluripotency and preventing premature differentiation.
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Wnt signaling pathway
A key signaling pathway in stem cells that influences cell fate decisions by stabilizing proteins like beta-catenin, promoting self-renewal in contexts like intestinal stem cells.
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Notch signaling pathway
A cell communication pathway in stem cells that regulates differentiation by transmitting signals across the cell membrane, often inhibiting differentiation in neighbors.
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Teratoma
A tumor that can form from pluripotent stem cells, containing tissues from all three germ layers, highlighting the risk of uncontrolled differentiation in stem cell therapies.
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Bone marrow transplantation
A procedure using hematopoietic stem cells from bone marrow to treat blood disorders by repopulating the patient's blood system with healthy cells.
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Cord blood banking
The collection and storage of blood from the umbilical cord, which contains hematopoietic stem cells, for potential use in treating diseases like leukemia.
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Regenerative medicine
A field using stem cells to repair or replace damaged tissues, such as growing new heart muscle from pluripotent cells to treat heart disease.
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Therapeutic cloning
The creation of embryonic stem cells through somatic cell nuclear transfer to produce patient-specific cells for treating diseases without immune rejection.
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Somatic cell nuclear transfer
A technique where the nucleus of a somatic cell is transferred into an enucleated egg cell to create an embryo that can yield embryonic stem cells.
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Ethical issues in stem cell research
Concerns about the destruction of embryos in deriving embryonic stem cells, leading to debates on the moral status of embryos and research regulations.
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Differentiation potential
The range of cell types a stem cell can become, determined by its potency level, such as pluripotent cells having broader potential than multipotent ones.
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Stem cell plasticity
The ability of stem cells to change their differentiation potential under certain conditions, allowing adult stem cells to adopt new lineages in some cases.
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Cancer stem cells
A subset of tumor cells with stem-like properties that can self-renew and drive tumor growth, making them a target for cancer therapies.
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Stem cell therapy for diabetes
Using stem cells, such as beta cell-derived ones, to replace damaged insulin-producing cells in the pancreas, potentially curing type 1 diabetes.
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Stem cell treatment for Parkinson's
Transplanting dopamine-producing neurons derived from stem cells into the brain to replace lost cells and alleviate Parkinson's disease symptoms.
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Blastocyst
An early embryonic stage consisting of an inner cell mass and an outer trophoblast, from which embryonic stem cells are typically derived.
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Inner cell mass
The cluster of cells inside a blastocyst that will develop into the embryo proper and is the source of pluripotent embryonic stem cells.
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Trophoblast
The outer layer of cells in a blastocyst that forms the placenta and other supporting structures, distinguishing it from pluripotent inner cells.
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Zygote
The initial cell formed by the fusion of egg and sperm, which is totipotent and divides to form the early embryo including stem cells.
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Morula
A solid ball of cells resulting from early zygote divisions, containing totipotent cells that can develop into a blastocyst.
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Gastrulation
The process in embryonic development where cells differentiate into the three germ layers, involving the organization of pluripotent stem cells.
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Organoids
Three-dimensional structures grown from stem cells that mimic organ functions, used to study development and disease in a lab setting.
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Yamanaka factors
The four transcription factors (Oct4, Sox2, Klf4, c-Myc) used to reprogram somatic cells into induced pluripotent stem cells.
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Dedifferentiation
The reversal of a specialized cell to a less differentiated state, similar to stem cells, enabling potential therapeutic reprogramming.
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Transdifferentiation
The direct conversion of one mature cell type into another without passing through a pluripotent state, using stem cell-like mechanisms.
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Lineage commitment
The point in stem cell differentiation where a cell irreversibly commits to a specific cell lineage, influenced by environmental signals.
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Stem cell markers
Proteins like CD34 or SSEA-1 expressed on the surface of stem cells, used to identify and isolate them for research and therapy.
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Asymmetric inheritance
The unequal distribution of cellular components during stem cell division, ensuring one daughter remains a stem cell.
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Stem cell quiescence
A dormant state in some stem cells that protects them from damage and allows activation only when needed for tissue repair.
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Germ layers
The three primary layers (ectoderm, mesoderm, endoderm) formed during gastrulation from pluripotent stem cells, each giving rise to specific tissues.
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iPSC reprogramming efficiency
The variable success rate of converting somatic cells to induced pluripotent stem cells, affected by factors like cell type and delivery method.
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Telomerase in stem cells
An enzyme that maintains telomere length in stem cells, enabling repeated divisions without aging, unlike in most differentiated cells.
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Microenvironment influence
The role of surrounding factors like growth factors and extracellular matrix in directing stem cell behavior and fate decisions.
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Stem cell exhaustion
The depletion of stem cell reserves due to factors like aging or disease, leading to impaired tissue regeneration.
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Chimera formation
The creation of an organism with cells from two different zygotes, often using stem cells in research to study cell contributions.
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Parthenogenesis in stem cells
The development of an egg without fertilization to produce stem cells, an alternative method with ethical implications.