Stem Cells

Stem cell

cells which have not yet differentiated which can divide an unlimited amount of times

Totipotent stem cells

can form any type of cell (including placental cells)

where totipotent cells are most common

first few divisions of a fertilised egg

Pluripotent stem cells

can form many types of cells but cannot form placental cells

Multipotent stem cells

can form a limited number of specialised cells

where multipotent stem cells are found

in adult mammals in the bone marrow

unipotent stem cells

cells which can only differentiate into a single type of cell

Main example of unipotent stem cells

cardiomyocytes (cardiac muscle cells)

function of cardiomyocytes

main type of heart cell, ensure the heart contracts to pump blood throughout the body

Transcription factors

proteins which select which genes should be transcribed for a specialising stem cell

where transcription factors attach to on DNA

the promoter region

what transcription factors do to ensure a gene is or isn’t transcribed

signal RNA polymerase to start or stop transcribing a gene

IPS (induced pluripotent stem) cells

created in a lab from adult somatic cells using transcription factors

The type of stem cells IPS cells are similar to

embryonic stem cells

what IPS cells allow scientists to do

express/activate any genes which were not previously expressed

why IPS cells may be more effective than a stem cell transplant

-transplant has to be from a different person so may reject

-IPS is the patients own stem cells