producing new cells Flashcards
what are stem cells?
unspecialised cells that all cells stem from
what are the two types of stem cells?
- embryonic stem cells
- tissue stem cells
where are embryonic stem cells found?
found in the embryo at a very early stage of life
where are tissue stem cells found?
found in the body throught life
- bone marrow
- muscles
- skin
- liver
why are stem cells needed?
they are needed by the body for growth and repair of tissue and to replace damaged cells
stem cells allow growth and repair by?
- cell division in order to self renew
- produce specialised cells
what is the ethical issue involving embryonic stem cells?
using embryonic stem cells involves destruction of the embryo which is unethical
how are stem cells used in modern medicine?
- to replace cells damaged by chemotherapy
- fights some cancers and blood related diseases
- for drug testing
- for regenerating tissues (e.g skin grafts)
what is mitosis?
cell division which produces two identical diploid cells
for growth and repair
why do cells undergo mitosis?
to produce new cells for growth and repair of damaged cells/tissue
what does mitosis maintain?
the diploid chromosome complement when producing daughter cells
what is the diploid chromosome complement?
number of chromosomes
what is stage 0 of mitosis?
long uncoiled chromosome not yet visible
what is stage 1 of mitosis?
- chromosomes shorten, thicken and replicate forming 2 identical chromatids
- chromosomes now visible
- nuclear membrane disappears
what is stage 2 of mitosis?
chromosomes line up at equator of the cell and spindle fibres attatch to chromosomes
