Stem Cells

Question 1

what is a stem cell?

Answer 1

a single cell that can replicate itself, or differentiate into many cell types

Question 2

what is the journey of a stem cell?

Answer 2

• all cells begin as stem cells, these are not specialised to a particular job, but are able to divide many times by mitosis to make new cells
• some stem cells then differentiae (develop new features) to become specialised cells, ones which have the structures and proteins needed to carry out a specific job in the organism

Question 3

what is differentiation controlled by?

Answer 3

the genes

Question 4

what happens during differentiation?

Answer 4

genes are switched off so that they cannot be transcribed - this ensures the only proteins produced in the specialised cell are the ones needed to carry out its particular job

Question 5

what are the two types of stem cell?

Answer 5

embryonic and adult

Question 6

what are embryonic stem cells?

Answer 6

they are found in the early form of the embryo - they can differentiate into any type of cell

Question 7

what are adult stem cells?

Answer 7

• adult stem cells are present in some tissues in organisms (from the time they have recognisable organs) - there are several different types
• they divide by mitosis and each type of stem cell can differentiate into a few different types of specialised cell

Question 8

how are stem cells used to treat many different diseases, repair damaged tissues and even new organs for transplant?

Answer 8

• we can transplant adult stem cells
• adult stem cells are easy to collect for treatment, but can only become a limited number of cell types
• scientists can also collect embryonic stem cells and culture them - grow large numbers in a lab