OCR Biology F215 Control, Genomes and Environment Fri 15 June 2012

Don't take this the wrong way. But i didn't think someone with your 'academics' would post that.
*after reading your sig*
but i was surprised when i saw you got rejected from your unis.
Do you know why you were rejected?

guys im revising for this ..and all im doing is rewriting my notes..but i still feel like im not remembering some of the stuff :/ how do you properly revise for this exam i hate bio -.-

for me the way to revise for biology is to read the text book a few times (i know its boring) then after doing old spec questions from old past papers then eventually move onto the new papers. i guess the first thing to do is to make sure u more or less understand most things and then practice loads, u learn new things wen u practice aswell. just revise efficiently, not to be rude but i dont see how rewriting ur notes or making notes from the text book is efficient because its already there u can jus read it lol

I actually have a genuine problem with OCR Biology. Some of the questions I do not understand the way the mark scheme does, I always answer it differently, correctly, but differently. Quite frustrating. I got an A for AS, but flopped and got a D in F214 in Jan. Has anyone had the same problem? I also find I tend to overcomplicate the question?...

haha i just find the nitrogen cycle hard to get around, mind boggling stuff lol

well ive asked for feedback but i would say it was due to either my ukcat score or personal statement or both :/

thankyou! (: is that how you get the A? just reading a textbook then doing past papers??? thanksss x

yeh its the most efficient way, all u need is a way for u to take in all the information. then the most important bit is doing all old spec and new spec past papers and learning from the mark scheme etccc

Hey guys,

Do we need to know the Hardy Weinberg equation? (as in learn it?) or will they give it to us?

we need to know it and we need to know how to apply it,
q+p=1
and p^2+2pq+q^2=1

we need to know it and we need to know how to apply it,
q+p=1
and p^2+2pq+q^2=1

This is going to be abit long, sorry. I am going to try to simplify it epistasis. Epistasis is bascially when two different genes on two different loci (loci means position on the chromosome) interact to affect one phenotypic charecteristic such as the colour of a flower. There are two types of how these genes can work together, one is antagonistically and one is where they work together (complementary). Antagonistic epistasis is basically where one gene will "mask/supress" the expression of the other gene. So you have two types of antagonistic, one which is recessive and one that is dominant.

The recessive epistasis is basically, if I have a recessive aa at one loci (lets say this is a white colour for flowers), it does not matter what gene comes after that, that specific aa will always be expressed in the phenotype. So aaBB/aaBb will give me the same white colour of the flower. The phenotypic ratio for recessive is 9:3:4. Whilst with dominant epistasis, ifI have Aa/AA at one loci (lets say this is a pink colour), it does not matter what gene comes after that , that dominant Aa/AA will be expressed in the phenotype. So AaBB/AABB/Aabb/AaBb will all give me the same pink colour. If you see the phenotypic ratio 13:1/12:3:1 it suggests dominant epistasis.

And with complementary epistasis, it means that the two dominant alleles at the two different loci work together to give the phenotypic expression. a 9:7 ratio suggests it is complementary epistasis.

The alleles at the first loci are epistatic (so they are doing the masking/suppressed) to the alleles at the second loci, which are called hypostatic(they are being masked/suppressed).

Erm yerh, alot of waffling sorry . If I have made any mistakes, please do correct me.

It is all the letters that confuse me :P
But thankyou!! That did help thankyou again!!!!

Yerh I would say so because the alleles at the first loci are thr epistatic alleles. So the first alleles are doing the "masking/supressing" and will be expressed in the phenotype. So in dominant epistasis, if there is a dominant allele in the first gene loci, it does not matter what comes after it. The second alleles at the other gene loci (in this case bb) is hypostatic (masked/supressed). Correct me if I am wrong

yes ur right thanks!
hows revision going?

Does anyone know of any good sites to revise F214 and F215? There seems to be loads of amazing sites for OCR A2 chemistry but none for biology