Chapter 22: Stem Cells and Cell Death

A collection of flashcards summarizing key concepts about stem cells and apoptosis based on lecture notes.

What are stem cells?

Stem cells are cells that can proliferate indefinitely.

What is the difference between symmetric and asymmetric cell divisions?

In symmetric cell division, daughter cells are identical in fate, while in asymmetric cell division, one daughter cell becomes a stem cell and the other becomes a differentiating cell.

What is apoptosis?

Apoptosis is a form of programmed cell death that occurs in a controlled manner without causing inflammation.

What factors contribute to maintaining the pluripotency of embryonic stem cells?

Three key transcription factors: Nanog, Sox2, and Oct4 help maintain the identity of embryonic stem cells.

What is necrosis?

Necrosis is a form of cell death resulting from acute injury where cells swell and burst, causing inflammation.

What is the role of Ca2+ during fertilization?

Ca2+ plays a crucial role in the process of fertilization by ensuring that one sperm fertilizes one egg.

What distinguishes pluripotent stem cells from totipotent stem cells?

Pluripotent stem cells can give rise to almost all cell types except for extra-embryonic tissues, while totipotent stem cells can form all cell types including those needed for embryonic development.

What is the function of embryonic stem cells?

Embryonic stem cells are pluripotent, meaning they can differentiate into any cell type in the body but cannot form placental tissue.

What initiates the restriction of cell fates during development?

Cell fate restriction is initiated by extracellular signals and asymmetric cell divisions.

What do adult stem cells require for their maintenance?

Adult stem cells require specific niches and signals from neighboring cells for their maintenance and proliferation.

What is the main niche for hematopoietic stem cells?

The main niche for hematopoietic stem cells is in the bone marrow.

How can somatic cells be transformed into induced pluripotent stem cells (iPS)?

Somatic cells can be reprogrammed into iPS cells using a combination of four transcription factors: Sox2, Oct4, KLF4, and Myc.

What is a key difference between intrinsic and extrinsic apoptosis pathways?

Intrinsic pathways are initiated by signals originating from within the cell, while extrinsic pathways are triggered by external death signals binding to death receptors.