1.1 Flashcards
germline cell
Cells are gametes (sperm and ova) and the stem cells that divide to form gametes.
stem cells
Stem cells are undifferentiated cells that have the ability to differentiate into specialised cells and can divide to produce more stem cells.
what do somatic cells divide by
Somatic Stem cells divide by mitosis to form more somatic cells.
what do germline cells divide by
Germline cells divide by mitosis and meiosis to produces haploid gametes
cellular diffrrentation
is the process by which a cell expresses certain genes to produce proteins characteristic for that type of cell. (This allows the cell to carry out a specialised function).
embryonic stem cells
Cells in the very early embryo can differentiate into all the cell types that make up the individual
(This means all genes in embryonic stem cells can be switched on so these cells can differentiate into any type of cell)
tissue stem cells
Tissue stem cells are involved in the growth, repair and renewal of the cells found in that tissue. They are multipotent.
(Tissue stem cells are multipotent as they can differentiate into all the cells types found at that particular tissue.)
theraputic uses of stem cells
corneal repair or reservation of damaged skin (skin graft).
ethical issues
Destruction of an early embryo can raise ethical issues and there are many arguments for/against the use of embryonic stem cells.
how do tumours form
Cancer cell divide excessively because they do not respond to regulatory signals.
This results in a mass of abnormal cells called a tumour
how do secondary tumours form
Cells within the tumour may fail to attach to each other, spreading through the body where they may form secondary tumours.
where are adult tissue stem cells found
in the skin or bone marrow
stem cells in bone marrow
stem cells in bone marrow can diffrrentiate into red blood cells , platelets and various forms of phagocytes and lymphocytes
