B2- Cell division Flashcards
What are stem cells?
undifferentiated cell that can differentiate into one or
more specialised cell types
What are adult stem cells?
stem cells from adults that can only differentiate into some cells
Where can adult stem cells be found?
Bone marrow
What are embryonic stem cells?
stem cells from embryos that can differentiate into certain specialised cells
Where are embryonic stem cells found?
early human embryos
What is therapeutic cloning?
patient’s cells are used to create an early embryo clone of themselves- stem cells from the embryo can then be used to treat the patient’s medical conditions
Give one advantage of using therapeutic cloning.
stem cells from the embryo are not rejected when transplanted because they have the same genes as the patient.
Give one advantage of using adult stem cells
fewer ethical issues as obtained from adults who can consent to their use
Give two disadvantages of using adult stem cells.
can take a long time for a suitable donor to be found
- can only differentiate into some specialised cell types, so treat fewer diseases
GIve two advantages of using embryonic stem cells
- can differentiate into any specialised cell, so can be used to treat many diseases
- easier to obtain as they are found in spare embryos from fertility clinics
Give two disadvantages of using embryonic stem cells.
- ethical issues surrounding their use, as every embryo is a potential life
- potential risks involved in treatment such as transfer of viral infections
What are plant meristems?
area where rapid cell division occurs in the tips of roots and shoots
GIve two advantages of using plant meristems to clone plants.
- rare species can be cloned to protect them from extinction
- plants with special features (eg disease resistance) can be cloned to produce many copies
Give one disadvantage of using plant meristems to clone plants.
no genetic variation so for e.g an entire cloned crop could be destroyed by a disease
What is cell division by mitosis?
body cells divide to form two identical daughter cells
What is the purpose of mitosis?
growth and repair of cells, asexual reproduction
What happens during the first stage of the cell cycle?
cells grow bigger, chromosomes duplicate, number of subcellular structures (eg ribosomes and mitochondria) increases
What happens during mitosis?
one set of chromosomes is pulled to each end of the cell and the nucleus divides
What happens during the third stage of the cell cycle?
the cytoplasm and cell membrane divide, forming two identical daughter cells
What is the term for cell division in bacteria?
Binary fission
