STEM CELLS
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What are: MERISTEMS +where are they found
MERISTEMS are zones of mitosis in a plant and it is the only place a plant can grow -they are found at the tips of shoots and roots and around the stem NOTE: meristem is a tissue
What type of cells are found at meristems and what can they form?
STEM CELLS • they can form any PLANT CELL for GROWTH
define: TOTIPOTENT + where are they found
stem cells that can form any body cell including extra embryonic tissues -found in early embryos
define: PLURIPOTENT + where are they found
stem cells that can form almost all body cells except extra embryonic tissues -found in early embryos(after totipotent stage)
define: MULTIPOTENT + where are they found
stem cells that can become certain cell types • found in adult tissues (bone marrow , blood)
define: STEM CELLS
An unspecialised cell that has the ability to differentiate into other types of cells (depends on the type of stem cell )
when do animals grow ? when do they stop growing
animals grow in the EARLY STAGES of their lives when they reach ADULTHOOD ,they stop growing
What are stem cells used for in medicine?
to treat diseases where cells CANNOT FUNCTION PROPERLY or are DAMAGED
what theory is used to treat type 1 diabetes (immune system attacks beta cells that produce insulin) why can bone marrow stem cells not be used?
CELL REPLACEMENT THEORY -beta cells injected into pancreas -bone marrow stem cells are multipotent and can only form certain types of cells ,they cannot form insulin producing beta cells
What is THERAPUTIC CLONING? (what does it do?)
it makes stem cells from a patients own cells so the risk of rejection is reduced
define: DIFFERENTIATION
when a cell becomes specialised to carry out a role I would say: when an unspecialised cell differentiates / becomes specialised to carry out a specific function or role
Why is differentiation important?
it makes them more efficient at carrying out their specific jobs I would also add: this helps the organism to grow ,repair and work more efficiently
TRUE or FALSE : therapeutic cloning doesn’t involve embryonic stem cells
FALSE - an egg cell from a woman is taken and nucleus removed, then a nucleus from a patient’s body cell is put into the empty egg cell ….
give a reason FOR and AGAINST stem cell research (3 each )
FOR: - it can treat patients who have currently untreatable diseases -use of embryonic stem cells in therapeutic cloning reduces the risk of rejection (developed from the patient ‘s own cells ) -many frozen embryos from IVF are thrown away (so this means that they are used effectively?) AGAINST: -worry that embryos might be seen as products instead of potential life -people disagree on what stage of its development an embryo should be considered and treated as a human -therapeutic cloning involves creating embryos and extracting their stem cells which destroys it in the process ( it is not right to create potential life then destroy it in the process)