Qualification > Sciences
Edexcel BIOLOGY Doubts!!!!
ksitna:
--- Quote from: Uchia on June 07, 2010, 09:20:33 pm ---cancer is when the rate of cell division is greater than the rate of cell death. Cancer could also form tumour which is abnormally living cells that invades other cells. Tumor could also break releasing small clumps of cells which we call it the metastasis method. The cancer cells are also able to live longer than normal healthy cells. Cancer could be formed by either a change in the enviroment or by mutation (gene changes). ok now for the 2 important parts about the gene mutation which causes cancer 1. supressor gene which removes the break on the cell cycle which increases the cell division. 2. protoncogenes which increase the amount of protein provided. The tar in the ciggeratte could cause this protoncongenes and the supressor thingiiis. As for the role of the enviroment u could talk about the uv light and how does it burn the skin and cause cancer + the melanin production where the uv causes the putitary gland to form MSH hormone, MSH could then join to receptor, move inside the cell and turn the gene that is responsible for the formation of tryosenase on. Tryosenase then converts the tryosin to melanin. Many melanin would join/get near to each other preventing the uv from reaching the cells which results in cancer and mutation
THANK YOUUU!!! :D
They might also bring u a normal graph and ask you to describe their values
that's everything
--- End quote ---
Uchia:
when they get near close we call it melasonomes
Uchia:
melanosomes****
Ibiza279:
i need help with gene expression and differentiation :( n also, im confused in learning the mitosis stages, can anyone give me an easier method :| sovvy fer the botherrrr :3
Kim:
--- Quote from: ksitna on June 07, 2010, 09:20:06 pm ---k can someone plz explain the maoa?
--- End quote ---
ok welll
MAOA is monoamine oxidase A
it break downs nuero transmitter such as serotonin and dopamine
if the level of MAOA is raised or decreased it causes mutations
low levels -nervous disorder
dependance on alcohol
parkinsons disease
high levels-risk takin and aggressive behavior
tension favors high release of MAOA
and maltreatment causes low release
this enzyme is produced with the help of a dominate gene located on the X chromosome
if there is to much of this enzyme it breaks down too many of the nuerotransmitters which can affect ur mood
hence it is linked with depression
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