2.5 - Stem Cells

Question 1

Potency (Of A Stem Cell)

Answer 1

Is its ability to differentiate to become more different kinds of cells

Question 2

Totipotent

Answer 2

can differentiate into any cell type and give rise to a new individual
e.g - zygote

Question 3

Pluripotent

Answer 3

can differentiate into any cell type
e.g - human embryonic stem cell

Question 4

Multipotent

Answer 4

can differentiate into a range of cell types within a lineage
e.g - hematopoietic stem cells (that specialize into various blood cells), adult bone marrow

Question 5

Unipotent

Answer 5

can only differentiate to form one cell type
e.g - skin cells

Question 6

Types Of Stem Cells

Answer 6

Adult → multipotent, unipotent

Embryonic → totipotent, pluripotent

Question 7

Embryonic Stem Cells

Answer 7

are found in the early embryo and can differentiate into any cell type

Question 8

Differentiation

Answer 8

describes the specialisation of a cell to perform a specific role

Question 9

Stem Cells

Answer 9

are undifferentiated cells in multicellular organisms that can give rise to differentiated cells or self replicate to produce more stem cells

Question 10

Why Are There Stem Cells?

Answer 10

• stem cells are also needed to produce differentiated cells to replace dead or damaged cells throughout the lifetime
• these stem cells are found in select populations in adult tissues and can give rise to a more limited range of cell types. For example, stem cells found in bone marrow give rise to a variety of blood cells
• once a cell has fully (terminally) differentiated, it is unable to divide to make more copies of itself

Question 11

Self-Renewal In Stem Cells

Answer 11

Stem cells must self-renew to ensure that they do not all differentiate in order to maintain an adequate population of stem cells