cell division (4.1.2) Flashcards
what is a chromosome?
made of DNA molecules so carries genes
In body cells normally found in pairs.
the cell cycle step one
The DNA replicates to form two copies of each chromosome.
the cell cycle step two (mitosis)
In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides.
the cell cycle step three
Finally the cytoplasm and cell membranes divide to form two identical cells.
what is a stem cell
A stem cell is an undifferentiated cell of an organism
which can create more cells of the same type
what is the function of stem cells from a human embryo?
can be cloned and made to differentiate into most different types of human cells.
what is the function of stem cells from adult bone marrow?
can form many types of cells including blood cells.
what is the function of stem cells from meristem tissue in plants?
can differentiate into any type of plant cell throughout life of the plant.
how are stem cells used in humans for treatment
in treatment such as may be able to help conditions such as diabetes and paralysis.
what is therapeutic cloning?
an embryo is produced with the same genes as the patient.
Stem cells from the embryo are not rejected by the patient’s body
may be used for medical treatment.
what are the risks of stem cell use?
transfer of viral infection
some people have ethical or religious objections
how can stem cells from plants be used
- Rare species can be cloned to protect from extinction
* plants with special features such as disease resistance can be cloned to produce large numbers of identical plants
