Biology — Stem Cells & Differentiation

What is a specialized cell?

a cell with a unique structure and function suited to a specific task

What is cellular differentiation?

the process that turns unspecialized cells into specialized cells

What is a stem cell?

an unspecialized cell that can differentiate into specialized cells

What are the two defining traits of stem cells?

potency and self-renewal

What is potency?

a stem cell's ability to differentiate into specialized cells

What is self-renewal?

a stem cell's ability to divide many times while staying unspecialized

Where are stem cells found?

in embryos, and in some adult tissues like the lungs, intestines, and skin

Why are stem cells needed in adult tissues?

those cells are often damaged, so stem cells allow regrowth and repair

What are the three levels of potency?

totipotent, pluripotent, and multipotent

What is a totipotent stem cell?

one that can become every cell type, including the tissues surrounding the embryo

Give examples of totipotent cells?

a fertilized egg, its first few divisions, and plant meristems

What is a pluripotent stem cell?

one that can become all body cell types, except the tissues surrounding the embryo

Which stem cells are pluripotent?

embryonic stem cells

What is a multipotent stem cell?

one that can only become the cell types within a specific tissue

Which stem cells are multipotent?

adult stem cells

Give an example of a multipotent stem cell?

intestinal stem cells, which only replace the intestinal lining

If all cells share the same DNA, how do cell types differ?

each type expresses only a subset of its genes

Does specialization involve gaining or losing genes?

no, every cell keeps the same genes but expresses different ones

What is a memory aid for the potency levels?

toti means all, pluri means many, and multi means several within one tissue

What is regenerative medicine?

using medical techniques to grow healthy cells that replace diseased or injured ones

What is one stem cell therapy in use today?

a bone marrow transplant

How does a bone marrow transplant work?

donor bone-marrow stem cells are infused into a patient, where they differentiate into blood cells