Qualification > Sciences

Edexcel BIOLOGY Doubts!!!!

<< < (32/139) > >>

ksitna:

--- Quote from: Psyclax on June 07, 2010, 09:14:16 pm ---can someone help me with january 2009 unit 2 question 1 b) i)
idk how the diagram should look like

--- End quote ---


well u kinda draw like lines or circles like


0(------)
0(-----)
0(----)   o and arrow going down

ksitna:

--- Quote from: kim on June 07, 2010, 09:15:32 pm ---well it is pretty simple
for eg lets take skin cancer
the colour of the skin is caused by melanin
melanin is produced by the tyrosinase enzyme
melanin is stored in specail cells called melanocytes in organelles called melanosomes
cancer is caused by genes and environment
cell divison is controlled by 2 types of genes
protoncogenes
and tumor supressor genes
UV radiations causes the conversion of protonco to onco genes and tumor supressor to tumor activator genes
which results in the uncontrolled division of cells and formation of tumor

also some general facts about cancer u shud know
cancer cells divide rapidly to form a mass of abnormally growing cells or a tumour which invades the surrounding tissues
the uncontrolled division is called metasis
a tumour that invades surrounding tissues is called malignant


--- End quote ---

Thank you sooo much!!!!

ksitna:
k can someone plz explain the maoa?

Uchia:
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


They might also bring u a normal graph and ask you to describe their values

that's everything

Uchia:
I think i was a bit late :P anyways i tried my best

Navigation

[0] Message Index

[#] Next page

[*] Previous page