i got 44.7% or something for hardy Weinberg not sure how.
and the first 5 marker put nitrification and ammonification then crossed it out and put about saprobiotic decomposers secreting enzymes etccc

Reply 905

Steerforth

Overall, not a bad exam set by AQA. They have certainly learnt from their mistakes on previous exam papers. I thought this one covered the specification reasonably well, quite a lot on genetics though, where they could have added either predation, food chains or speciation.

What do you guys think?

Reply 906

Stratos

Original post by Rickesh

I put directional because the environment is changing and the phenotypes also change?

Yeah that's what I put there was a selection pressure for those who had allele T therefore it moved towards allele T.

Original post by tehsponge

That Hardy Weinberg one REALLY threw me. First of all, you didn't even have to use the HW equation, which it told you to use. Also 4% seemed really low, but thats what everyone else got in my class.

It was unconventionally simple, I thought there had to be something behind it but I just had to square it and then make it a percentage, so I got 4%. too bad that it was the only hardy weinberg related question however I luckily skipped that part in revision since I couldn't be bothered so it came out good for me.

Reply 907

Laura-Robbie

Original post by alicetalbot

It favoured one allele therefore must be directional surely? As it favours one extreme

that does seem to make most sense, i guess directional wins :frown:

oops

Reply 908

tehsponge

Original post by cws121

both extremes wernt being eliminated though, and thats what happens with stabalising, i could be wrong though, thats just what i think

But how would you know if the T allele was an extreme? I mean if they're both extremes, then what is in the middle? O_o I thought that T had to be the mean/average allele, as it had a higher allelic frequency, whereas t was just 4%...

Reply 909

cleo101

Original post by Boo!xx

i did

i put 50:50 haha

Reply 910

budmed

Original post by tehsponge

I put stabilising but I think it could have been either...

I put down stabilising because although the population was reduced due to poaching they where then put in a conservation? therefore the enviroment is actually stable when the scientists are testing for recessive alle but to be fair i think its not what you put down for your answer but how you back it up, furthermore the selection pressure will be for a funtioning protein TT and tt will be the extremes and Tt will be the medium, why will it be directonal if your removing Tt which phenotype is the same as TT. Im sorry someone said a carbon cycle? I cant remember that? there was a nitrogen cycle, a calvin cycle and another essay cant remember what because I did it first but the carbon dioxide was in relation to calvin cycle.

(edited 12 years ago)

Reply 911

SK-mar

Original post by Stratos

I wrote that the nutrients were used to synthesize proteins e.g. microfibrils in muscles(actin fillament and myosin) therefore growth.

I wrote about extracelular decomposition, but first about intracellular digestion in invertebrates which digest the dead leaves into simpler organic molecules, afterwards saprobionts would further decompose the organic matter by releasing enzymes which break down the organic molecules and then absorb the usefull substances, ammonia is a waste product and is released into the atmosphere, nitrifying bacteria in the soil would convert ammonia into NO2 and then further nitrify into NO3, NO3 is soluble and can be absorbed into the roots of plants by active transport where it's used for biosynthesis(DNA replication, protein synthesis).

I wrote the same for the horses question!

for the decomposition one i wrote:

- decomoposers digest by extracellular digestion
- in doing so produce ammonium ions in soil
- these are converted into nitrates via nitrites by nitrifying bacteria
- nitrates used for protein synthesis, or nucleic acids
- microorganisms also respire aerobically releasing CO2
- CO2 can be taken in through stomata for photosynthesis
- products of photosynthesis, hexose sugars such as glucose which can be used in growth!

I also got 4% for hardy weinberg...

Reply 912

D*Star

that exam was soo stupid , i got an E last time i bet i got an E again.

Reply 913

SK-mar

Original post by Laura-Robbie

i put 50:50 for the cats but i wasn't too sure

I put 1:1

Reply 914

xbabycakes

4% for hardy weinburg and I put directional as it's one extreme but that could be wrong. I got the cat one wrong.. I somehow got 3:1 but it's 1:1 I think. Bahhh.

I thought the rest of the paper was ok.. but the mite question!? wtf! It started out alright but got more ridiculous as the question went on. Oh well, onwards and upwards to biol 5 now.. Have a feeling I won't get higher than a C.

Reply 915

Reccoshai

Original post by cleo101

i put 50:50 haha

haha same! :colondollar:

Reply 916

tehsponge

Original post by SK-mar

I put 1:1

I put 1:3 O_o This thread is depressing...

Reply 917

D*Star

on the last q i talked about carbon cylce and it was meant to be calvin cycle oops.

Reply 918

xbabycakes

Original post by cleo101

i got 44.7% or something for hardy Weinberg not sure how.
and the first 5 marker put nitrification and ammonification then crossed it out and put about saprobiotic decomposers secreting enzymes etccc

Well I put both so :P hopefully I've got some marks

Reply 919

SK-mar

I put stabilising selection because the recessive allele was present in such small numbers (only 4% from hardy weinberg question) and then went down to even lower which suggest it was at an extreme of the total alleles. therefore the decrease in recessive alleles means there were more alleles produced that weren't recessive and so closer to the middle of the range of alleles where most are present so its STABILISING SURELY :biggrin: