Module 5 Flashcards
(49 cards)
What is cell differentiation?
The process by which a less specialized cell becomes a more specialized cell type, developing unique structural and functional characteristics (e.g., blood, muscle, skin cells).
What can cells do after division regarding their fate?
They can remain identical to the parental cell, differentiate into a specialized cell, or undergo apoptosis (cell death).
What are the two mechanisms of cell division that produce different daughter cells?
Asymmetric cell division and symmetric cell division.
What role do molecular signaling pathways play in differentiation?
They determine cell fates by influencing how cells respond to developmental signals, which can change over time.
How do asymmetric cell divisions affect cell fate in C. elegans?
They segregate specific cellular components (e.g., P granules) into the founder cell, influencing the developmental fate of daughter cells through signaling pathways.
What are stem cells classified by?
Their degree of specialization and the types of daughter cells they produce, known as potency (totipotent, pluripotent, multipotent, unipotent).
What are totipotent stem cells?
Cells that can develop into any cell type of the body, including both embryonic and extra-embryonic tissues, like those forming the placenta.
What is the difference between pluripotent and totipotent stem cells?
Pluripotent cells can develop into most tissues necessary for fetal development but not extra-embryonic tissues, while totipotent cells can develop into all cell types, including those tissues.
What are multipotent progenitor cells?
Cells that can give rise to multiple but limited cell lineages (e.g., hematopoietic stem cells can develop into several types of blood cells).
What is a unipotent cell?
A cell that can differentiate into only one type of tissue or cell type, such as epidermal keratinocytes in the skin, which have self-renewal properties.
What is Waddington’s landscape model of stem cell differentiation?
It suggests that stem cells move irrevocably to more differentiated states over time, akin to a marble rolling down a hill, with specific gene networks shaping these differentiation paths.
What is the importance of stem cell niches?
Tissue stem cells require a specialized microenvironment for maintaining their stem cell properties, provided by neighboring specialized cells through signaling molecules.
How can mouse embryonic stem (ES) cells be maintained in culture?
They can be cultured to remain pluripotent, retaining the ability to differentiate into various cell types.
What are the ethical issues surrounding human embryonic stem cells?
They relate to the potential therapeutic approaches for tissue regeneration and repair, alongside concerns about the moral implications of using human embryos.
What is Waddington’s landscape in relation to cell differentiation?
It describes how differentiated cells can be programmed in vitro or in vivo to revert to a stem-like state, illustrating the concept of plasticity in cell fate.
Do all cells have the same genes?
Yes, all cells in an organism generally have the same genetic information; however, different genes are expressed in different cell types, leading to their unique functions.
What was the significance of Dolly the sheep?
Dolly was the first mammal cloned from an adult somatic cell, demonstrating that differentiated cells can be reprogrammed to become pluripotent.
What is SCNT and its potential use in therapy?
Somatic Cell Nuclear Transfer (SCNT) involves transferring a nucleus from a somatic cell into an enucleated egg cell, potentially used for therapeutic cloning and regenerative medicine.
What was the hypothesis behind Yamanaka’s Nobel Prize-winning research?
Introducing a limited number of genes into a differentiated cell could reprogram that cell to a pluripotent stem cell.
What was the approach taken by Yamanaka to identify genes for stem cell reprogramming?
He compiled a list of candidate genes essential for “stemness,” developed a cell assay based on fibroblasts, and tested the effects of gene introduction on these cells.
How many genes did Yamanaka initially study, and what was the outcome?
He studied 24 genes, finding that while individual genes had no activity, all 24 together induced pluripotency through G418 resistance.
Which four genes did Yamanaka identify as necessary and sufficient for inducing pluripotency?
Myc, Klf4, Sox2, and Oct4. These genes can reprogram fibroblasts into induced pluripotent stem cells (iPS cells) with characteristics similar to embryonic stem cells.
What are some applications of iPS cells?
Patient-derived iPS cells can differentiate into various cell types, and they have been used to model diseases like Alzheimer’s, producing neurons that exhibit disease-specific characteristics.
How do neurons derived from Alzheimer’s disease (AD) iPS cells respond to treatments?
Neurons from AD iPS cells produce active _-amyloid and Tau and can respond to secretase inhibitors, providing insights into disease mechanisms and potential therapies.
