Stem Cells

Question 1

Definition of a stem cell

Answer 1

Undifferentiated cells that can continually divide and become specialised

Question 2

What is differentiation

Answer 2

Process by which stem cells become specialised

Question 3

What are the different types of stem cells

Answer 3

Totipotent
Pluripotent
Multipotent
Unipotent

Question 4

What is a totipotent stem cell

Answer 4

Can divide and produce any type of body cell

Occur only for a limited time in early mammalian embryos

During dev translate only one part of dna resulting in cell specialisation

Question 5

What is a pluripotent stem cells

Answer 5

Found in embryos and can become almost any type of cell

Used in research to be used to treat human disorders e.g regrow skin cells to replaced those damaged by a burn
Issues - continually divide to create tumours, therapeutic cloning, destroying embryo

Question 6

What are multipotent stem cells

Answer 6

Found in mature mammals - in bone marrow

Can differentiate into a limited number of cells

Question 7

What are unipotent stem cells

Answer 7

Found in mature mammals

Can only differentiate into one type of cell

Question 8

Sources of stem cells in mammals

Answer 8

Embryos up to 16 days after fertilisation (pluri)

Umbilical cord blood/placenta/bone marrow (multi)

Question 9

What are induced pluripotent stem cells (iPS cells)

Answer 9

Take a adult somatic (body) cell and manipulate dna in cells by using transcription factors (turn on all genes) — induced to become pluripotent again (return to state of pluripotency)

No cloning involved or destruction of embryos

Self renewal properties and can divide unlimitedly