AS Biology Edexcel IAL Unit 1 & 2 2015

Alright thanks! I reallly hope this paper would be easier that the unit 1.

I don't think Unit 1 was actually HARD. Just very unpredictable... But yeah I'm with you

I was so pissed off with that graph :P
Anyways, hopefully this is gonna be good.

haha Ikr? yeahhh... Good luck

unit 1 wasn't that hard but too lengthy! and the question structures were kinda weird plus they tried something new this time (that 3-D graph)
I get the feeling the unit 2 gonna be the same and yeah some new things definitely popping up, that weren't before!

Hope not

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sorry if I've scared you! even I don't support my thinking capabilities at times!!

so how many papers have u all done?
I did june 11-to june 14, and jan 12 and 13... will also do 14
ive noticed things repeat.. and for our unit 2, maybe the first chap will be asked more than the second one...

The totipotent cell will divide and differentiate into a pluripotent cell by activated genes which produce mRNA which will be translated into specific proteins that will modify the cell and differentiate it then the pluripotent cell will differentiate into a multipotent cell

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Hi can someone explain to me how natural selection takes place?

Thank you so much , that seems right but doesn't cell differentiation produce a specialised cell eg red blood cell as all genes are switched off in a specialised cell? I think multipotent cells still have a active genes ?

I'll try, from the top off my head...

(There are different alleles at one loci of a chromosome coding for the same characteristic within the gene pool of a species (polygenic inheritance)

SO..
There is a selection pressure (such as change of climate or increased predators)
.Only individuals carrying the "advantageous allele"/advantageous characteristics (such as certain behaviour or fur coat for camouflage etc) will survive and breed
Advantageous allele is passed to their offspring
The offspring have a better chance of survival until the next selection pressure arrives, they reach adulthood and breed, frequency of advantageous allele increases in the gene pool
Fairly soon the "disadvantageous allele" will have died out, now all individuals in the species have this new characteristic, they have adapted/evolved
This can only happen thanks to polygenetic inheritance