AQA Biology Unit 4 January 2011

can anybody help with this:



(c) In a population, 168 had red wings (dominant) and 32 had black wings (recessive). Showing your working in each case, calculate the frequency of:
(i) the r allele;


(ii) the R allele.


answers are 0.4 and 0.6 but i got 0.16 for i).......


never mind - i realised i've worked out rr, so need to square root for r. duh =)

can anybody help with this:



(c) In a population, 168 had red wings (dominant) and 32 had black wings (recessive). Showing your working in each case, calculate the frequency of:
(i) the r allele;


(ii) the R allele.


answers are 0.4 and 0.6 but i got 0.16 for i).......


never mind - i realised i've worked out rr, so need to square root for r. duh =)

I dont know if you guys can help me because I'm doing the OCR paper but it is A2 biology, i just couldnt find a thread for it. Do you know what it means when it says - 'you can measure the rate of photosynthesis experimentally by measuring the rate of increase in dry mass of the plant'. Thanks in advance!

i think the dry mass (biomass) of the plant will increase as the rate of photosynthesis increases. This is because as more photosynthesis occurs, more carbohydrates (glucose) are produced, if you refer to the photosynthesis equation. So if these are more carbohydrates the biomass will be greater. for AQA we have to know about the uptake of oxygen to measure the photosynthetic rate so i'm not sure if what i said earlier was 100% correct.

Thank you!

Your welcome. When's your exam? Good luck for it

Extracellular digestion literally involves the saprobiotic microorganisms secreting enzymes onto the dead organic matter. Process of enzymes and substrates and break down is litterally that learnt in Biol1. Basically, in the carbon cycle the saprobiotic's will produce co2 when they respire the products of digestion whilst in the nitrogen cycle they will produce NH3 gas instead of CO2. In eutrophication there is not normally any sapribiotic microorganisms invloved is there?

When in the nitrogen cycle are there saprobiotic micro-organisms?
Yeah in eutrophication there are saprobiotic mircroorganisms.

It's when they decompose the dead matter, it's the ammonification process because they convert dead matter which is converted into ammonia gas and then ammonium ions (NH4+)

Eutrophication

1) Leeching occurs, nitrates enter a watercourse i.e . stream, lake.
2) This increase in nitrates leads to an algal bloom of those algae on top of the water.
3) Significantly less light is available to plants at the bottom of the water.
4) Photosynthesis and hence glucose production cannot occur so plants begin to die.
5) With fewer plants producing O2, there is an increased interspecific competition for 02
6) Fish, plants and other aquatic organisms die.
7) Anaerobically respiring bacteria decompose the dead matter, releasing co2 and acids. (Theres the decomposers, not sure if they are saprobiotic.)
8) Water becomes a mucky soup.

Thats how we were taught it

Do you think we will need to know the specific amounts of energy yields at each stage e.g. amounts of rNAD and ATP produced? xx

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