A2 Biology OCR June 2015 Revision Thread

Original post by tewas

would i be able to say no repeats for the reliability one?
Also so annoyed that I put FEBADC first then crossed out B and put another A :frown:

was the first behaviour type, kinesis?
I wrote the chain termination method because that was in the context of the question?
The synoptic stuff ruined me, good for people who retook F212 though :frown:

First behaviour was reflex.

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Reply 4822

tewas

Original post by Captain Anonymous

First behaviour was reflex.

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for gods sake, put that first then crossed it hate myself

Reply 4823

tewas

possibly got around 66-70, still an A, anybody hazard a guess at the approx. UMS?

Reply 4824

hajs

11

Original post by Student23478

Hi guys for the % efficiency Q cud u get marks for net producvity / net producvity of previous tropic level??

i think so, well thats what i wrote anyway lol

Reply 4825

bengali mandem

Original post by tewas

possibly got around 66-70, still an A, anybody hazard a guess at the approx. UMS?

118-128 ums

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Reply 4826

Student23478

Original post by hajs

i think so, well thats what i wrote anyway lol

Did you also talk about gross productivity first and also biomass etc

Reply 4827

Student23478

For the sepreation question on DNA did anyone talk about gel electrophoresis ? About making sure the same size so base sequence can be read ?

Reply 4828

tewas

Original post by Student23478

Did you also talk about gross productivity first and also biomass etc

my answer for this was such a mess and quite incoherent but i put a range of answers like dry organic mass, pyramids of biomass and calorimeter and measuring the temp rise of water, hopefully would get the marks?

Reply 4829

bengali mandem

Original post by Student23478

For the sepreation question on DNA did anyone talk about gel electrophoresis ? About making sure the same size so base sequence can be read ?

For this question, some people were talking about radioactive nucletodies and shiz

BUT IIRC, the question said how you would separate dna fragments... So it must be electrophoresis

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Reply 4830

ekk123

11

The bit with the flies with the 1:1:1:1 ratio, could you have said the difference was due to epistasis??

Reply 4831

Bomb calorimeter isn't needed. You say how the herbivore loses energy through faces, respiration and movement it would all that was required was to talk about it primary productivity and how it forms net by taking away respiration. The % available (denominator over available in herbivore after all those reductions) x 100

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Reply 4832

AsianBeauty

Grade boundaries for a* ?

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Reply 4833

hajs

11

Original post by Student23478

Did you also talk about gross productivity first and also biomass etc

yeah omg lol
and then spoke about loss of energy through photosynthesis and respiration (measured using respirometer)

Reply 4834

bengali mandem

Original post by AsianBeauty

Grade boundaries for a* ?

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73

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Reply 4835

Original post by bengali mandem

For this question, some people were talking about radioactive nucletodies and shiz

BUT IIRC, the question said how you would separate dna fragments... So it must be electrophoresis

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You had to make the link to the nucleotide sequencing and not just describe electrophoresis.

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Reply 4836

Koloterrorita

8

Original post by ekk123

The bit with the flies with the 1:1:1:1 ratio, could you have said the difference was due to epistasis??

Genes were linked hence a big 1:1 and a small 1:1 ratio

Reply 4837

A* will be 72 I think

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Reply 4838

ChoccyPhilly

13

Original post by Koloterrorita

Genes were linked hence a big 1:1 and a small 1:1 ratio

Did I have to say autosomal linkage or would I getaway with just linkage?

Reply 4839

Lizzieee4