B2 - Cell division Flashcards
What is a stem cell?
undifferentiated cells that can differentiate into a specialised cell to carry out a function
What are adult stem cells?
stem cells from adults that can only differentiate into certain specialised cells
Where are adult stem cells found?
bone marrow
What are embryonic stem cells?
stem cells from embryos that differentiate into any cell
Where are embryonic stem cells found?
early embryos - usually from spare embryos from fertility clinics
What is therapeutic cloning?
parent cells are used to create early embryo clone of themselves - embryo’s stem cells can then be used to treat patients medical condition
one advantage of therapeutic cloning
stem cells cannot be rejected because they are from the same genes as the patient
one advantage of using adult stem cells
fewer ethical issues - adults can consent to use of their cells
two disadvantages of adult stem cells
- can take a long time for suitable donor to be found
- only differentiate into some specialised cells so treat fewer diseases
two advantages of using embryonic stem cells
- differentiates into any cell type so can be used to treat many diseases
- easier to obtain as they are found in spare embryos at fertility clinics
two disadvantages of embryonic stem cells
- ethical issues - every embryo has a possible life
- potential risks with treatment like transfer of viral infections
what are plant meristems
area where rapid cell division occurs in the roots and shoots
two advantages of using plant meristems to clone plants
- rare species can be cloned to protect them from extinction
- plants with special features (e.g. disease resistance) can be cloned to produce many copies
one disadvantage of using meristems to clone plants
no genetic variation - entire crop can be destroyed by one disease if they have no resistance to it
what is cell division by mitosis
body cells divide to from two identical daughter cells
