biology aqa (b) mod 5 environment

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Reply 40

holzy_baby

Goku_ssj4

ermm i put that random co-ordinative number generation but i think thats completely rong!:|

huh? xx

Reply 41

Gaz031

belis

We know detailed structure of amino acid from Module so it is no secret for anybody that NH2 group is there. And if it is easier to convert or not that is purerly my assumption.

Erm, isn't this Biology and not Chemistry? If it's so easily convertable into amino acids then why don't plants absorb ammonia?

Lets agree to disagree :smile:

Reply 42

joshdajoker

It's not ammonia as a species of nitrifying bacteria are needed to convert ammonia to nitrite then nitrate and no such mechanism was shown on the diagram.

And no Nitrites or Nitrates where mentioned in the diagram. I also understand that leguminous plants have nitrogen fixing bacteria and not nitrifying bacteria.

I talked about a mutation altering the base sequence and thus causing a different amino acid sequence to be built up in translation, so a protein has different structure and thus different properties, making it resistant.

Fair enough but I think this is wrong and wont gain credit. I think the key to the question was the fact that both parents were susecptible to the disease but could produce young who were resistant.Your example could apply to any parents of organisms. I think they wanted you to pick up on the fact that the gene for resistance is recessive and that they could produce offspring with resistance should they both pass on the recessive resistant gene.

Reply 43

sokas

leguminous plants have nitrogen fixing bacteria so they take nitrogen from the air and convert it to ammonia which is then made into amino groups which is then used as a source of amino acids for the plant. The enzyme used by the plants is nitrogenase, so I put X and Y as ammonia and glucose... either way it was only worth one mark!

Reply 44

belis

Erm, isn't this Biology and not Chemistry? If it's so easily convertable into amino acids then why don't plants absorb ammonia?

Lets agree to disagree

I think I have the answer that will made us bot happy. Ammonia is initialy produced in the first nitrogen fixation reaction but then it is converted into nitrate which can be absorbed by plants. I think both should be acceptable as an answer. I realy need to stop thinking about mysterious molecule X as this will drive me creazy :biggrin:

Reply 45

joshdajoker

belis

I think you need to stop thinking about biology full stop. You have 370/390 UMS :biggrin:

Reply 46

belis

I am thinking about that question not becouse I am so conserned about 1 stupid mark but becouse I am simply curious what is the right answer and why.

Offtopic remark: I think that the main problem of educational system in UK is concentraiting to much on exams and too little on studying just for gaining some new knowledge (I am not going to say for plesure as it takes it one step too far :biggrin:

Reply 47

Gaz031

I can run with that that, though as you're applying to do medicine I suppose you're likely to be more informed than I about this subject.
I can afford to give up the mark though. There was more than enough 'gift' marks in BYB4 and BYB5 for A grades (eg synaptic transmission, accomodation, diabetes, eutrophication, hedgerows, monoculture) and a few extra UMS in case the synoptic module goes badly.

Offtopic remark: I think that the main problem of educational system in UK is concentraiting to much on exams and too little on studying just for gaining some new knowledge (I am not going to say for plesure as it takes it one step too far

Whenever a subject seems to start getting really interesting you realise that you're moving off the syllabus :rolleyes:

Reply 48

Vijay1

Gaz031

But how do plants use ammonia to produce amino acid? :confused:

Amino acids are made up of a carboxylic group -COOH attached to a amine group -NH2 to get NH2COOH

Amine is ofcourse a derivative of ammonia. So Ammonia both as a fertliser and a mineral is absorbed by plant.

Assumed knowledge from Bio modules 1 and 2

Reply 49

bricktops

erm ok then, for the first question about carrots i put that increase in mass, due to increase in growth due to exponential phase and no limiting factors, then stationary phase due to lack of light and build up of toxic substances. as you can see i brought a bit of module 7 knowledge in. but do you thinks thats right.

Reply 50

Gaz031

Vijay1

Amino acids are made up of a carboxylic group -COOH attached to a amine group -NH2 to get NH2COOH

In my unit one book it distinctly calls it an 'amino' group,

Amine is ofcourse a derivative of ammonia. So Ammonia both as a fertliser and a mineral is absorbed by plant.

I've never heard the word 'amine' before. Why does my unit 5 textbook state that ammonia (from saprophytic decompostion) need to be converted into nitrite and then nitrate before it can be absorbed by plants and used to produce amino acids?

Reply 51

Gaz031

bricktops

Briefly I put that as the nutrients per area are constant as you put more plants per area then they absorb a greater proportion of the nutrients to make a greater amount of biomass, but after a certain density increasing the number of plants no longer increases total biomass after 120 days as all nutrients have been converted into carrot structures.

Reply 52

justchar

reading all these makes me sad. i dont think i gained a single mark :frown:

Reply 53

Gaz031

justchar

reading all these makes me sad. i dont think i gained a single mark :frown:

Of course you have. There were enough giveaway marks in BYB4+BYB5 to get >=C
Stay positive! Don't fall into the trap of thinking back about the exam negatively just because you found it stressful.

Reply 54

nayanayan

Not to be silly or anything, but IS THERE ANYONE WHO IS LIKE PROPER GOOD AT BIOLOGY LIKE A**** PERSON WHO FOUND THE BIOLOGY PAPER HARD YESTERDAY FOR MOD 4 AND 5 :tsr: