U1KA1 Flashcards
What are somatic cells?
Any cells apart from the cells involved in reproduction.
What do somatic cells do?
they form tissues in the body and can be specialised for specific functions.
How do somatic cells divide?
by mitosis
What are somatic cells essential for?
growth and repair of tissues
What are germline cells
cells that form gametes (sperm and ova)
How do germline cells divide
mitosis and meiosis.
Germline stem cells can also divide by ______ to form haploid gametes.
meiosis
What are the two division stages in meiosis?
- homologous chromosomes are seperated
- chromatids are pulled apart.
What is cellular differentiation
the process by which a stem cell expresses certain genes to produce proteins characteristic for that type of cell.
What does cellular differentiation allow a cell to carry out?
specialised functions.
an example of cellular differentiation?
a cell in the heart muscle has the genes for insulin production switched off, but the genes for respiration enzymes switched on.
What are the two types of stem cells?
embryonic and adult tissue stem cells.
What can embryonic cells do?
differentiate into all the cell types that make up the individual.
embryonic stem cells are ______.
pluripotent
where are embryonic stem cells found?
very early embryo
What can adult tissue stem cells do
differentiate into all types of cell found in a particular tissue, involve themselves in the growth, repair and renewal of the cells found in that tissue
adult tissue stem cells are _______.
multipotent
Example of adult tissue stem cells differentiating?
blood stem cells located in bone marrow can give rise to red blood cells, platelets, phagocytes and lymphocytes.
What are the two uses of stem cells?
therapeutic and research uses.
What does it mean when stem cells can be used therapeutically?
to repaid damaged or diseases tissues or organs.
What are 2 examples of therapeutic use of stem cells?
skin graft and cornea transplant.
How does a skin graft work and what is it used for?
its used to treat large areas of burned or damaged skin. To provide a skin graft that is identical to the patient’s DNA. Cells taken from undamaged area and grow new skin in lab. Then grafted onto the burned patient.
How does a cornea transplant work and what is it used for?
used to treat the protective layer over the surface of the pupil and iris of eye. stem cells can be removed from healthy area and grow cornea in lab, then replacing it.
How can stem cells be used for research?
Potential to treat most human diseases, studying them meaning humans gain a better understanding, can mimic diseases, also possible to test medical drugs.
what are the ethical issues of using stem cells
embryonic stem cell research requires the destruction of an embryo. consider this as the destruction of a potential human life.
How do cancer cells occur?
through mutations in specific genes of cells can cause excessive cell division.
Why do cancer cells excessively divide?
because they do not respond to regulatory signals.
what is the mass of rapidly dividing cells formed called?
a tumour