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    (Original post by wwwwwwwwwwwf)
    It was biological control for sure

    Chemical control would be something like DDT. The Bt is a bacteria, not a chemical so it has to be biological.


    Bacillus thuringiensis (or Bt) is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide.

    source : https://en.wikipedia.org/wiki/Bacillus_thuringiensis

    Sorry for the bad news though, it was a really tough question


    I know love but it really is chemical. Bt is notoriously famous as a "pesticide " .. lol even sold on ebay as a "pesticide" 😂😂
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    I feel exactly the same, I was replying on BY4 to bring my grade up as I revised so much and was getting straight a's on the past papers. I honestly feel horrible at how it went, was relying on this as I'm a lot less confident on BY5 and I'm now scared BY5 will also be stupidly hard and 100% application.
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    (Original post by Mr Average.98)
    I know love but it really is chemical. Bt is notoriously famous as a "pesticide " .. lol even sold on ebay as a "pesticide" 😂😂
    http://www.nrcan.gc.ca/forests/fire-...-insects/13401

    http://www.biocontrol.entomology.cor...s/bacillus.php


    https://www.fruithillfarm.com/protec...edator-bt.html
    Also sold here as a biological control
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    I'm team #biological
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    (Original post by Mr Average.98)
    I know love but it really is chemical. Bt is notoriously famous as a "pesticide " .. lol even sold on ebay as a "pesticide" 😂😂
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    pretty sure it's biological... a pesticide is a poisonous chemical, whereas the question was talking about a bacteria...
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    Can go further into it and say
    Biological control is defined as the control of a pest using organisms that are either predators or parasites of the pest.And a predator is defined as an organism that preys upon another organism. Bt is a bacterium, so therefore is an organism and a predator of the catapillarFor the Bt to be a chemical control agent, it would have to be a chemical, and bacterium isnt a chemical so yea :/
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    (Original post by Tamsyng)
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    pretty sure it's biological... a pesticide is a poisonous chemical, whereas the question was talking about a bacteria...
    Right. Clearly there is both refuting evidence for each other . But thinking critically to given case study. The Bt produces "toxins" which kills catepillar by destroying its guts and etc . So omission is the toxins is insinuating that it may be chemical .. but i will say that biological control do have substance to its argunment. Maybe biological...? Who knows ...🙈
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    http://www.strawpoll.me/10503390

    lol
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    Lol...good idea tho.

    Btw .. lets say if someone got the control question wrong (1 mark) .. would they also loose the 3 marks for continuing Qs asking for advantages and disadvantages .. or will they not.

    Losing 1 mark is better than 4 right?
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    (Original post by Mr Average.98)
    Lol...good idea tho.

    Btw .. lets say if someone got the control question wrong (1 mark) .. would they also loose the 3 marks for continuing Qs asking for advantages and disadvantages .. or will they not.

    Losing 1 mark is better than 4 right?
    They may do a markscheme like
    if biological control answered in (i) then ...biolocial control adv/disadv

    If chemical control answered in (i) then allow ....chemical control adv/disadv
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    (Original post by Mr Average.98)
    Lol...good idea tho.

    Btw .. lets say if someone got the control question wrong (1 mark) .. would they also loose the 3 marks for continuing Qs asking for advantages and disadvantages .. or will they not.

    Losing 1 mark is better than 4 right?
    If they read the question correctly they wouldn't, because it asked using the information given, otherwise if they got the control wrong and gave disadvantages for the wrong control then they'd lose the marks.
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    (Original post by wwwwwwwwwwwf)
    They may do a markscheme like
    if biological control answered in (i) then ...biolocial control adv/disadv

    If chemical control answered in (i) then allow ....chemical control adv/disadv
    Seems unlikey to me. Answer is not up for debate . Either its chemical or biological. .. lets say i write chemical but answer was biological.

    But when it comes to adv i say: highly selective to one pest specie (dont harm other species)
    Disadv: costly and time taking to apply all over the leaves effeciently
    AND pests can develop resistance to the toxins produced by Bt ( these were my adv and disadv points) ?? Is it creditable ??
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    (Original post by Mr Average.98)
    Seems unlikey to me. Answer is not up for debate . Either its chemical or biological. .. lets say i write chemical but answer was biological.

    But when it comes to adv i say: highly selective to one pest specie (dont harm other species)
    Disadv: costly and time taking to apply all over the leaves effeciently
    AND pests can develop resistance to the toxins produced by Bt ( these were my adv and disadv points) ?? Is it creditable ??
    That's not what i mean, couldn't word it properly.

    I meant that if you answered chemical and it was biological, they may allow chemical advs and disadvs in the following two questions.
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    (Original post by Mr Average.98)
    Seems unlikey to me. Answer is not up for debate . Either its chemical or biological. .. lets say i write chemical but answer was biological.

    But when it comes to adv i say: highly selective to one pest specie (dont harm other species)
    Disadv: costly and time taking to apply all over the leaves effeciently
    AND pests can develop resistance to the toxins produced by Bt ( these were my adv and disadv points) ?? Is it creditable ??
    You would Deffo get the marks for reason, because whether or not you out biological or chemical you had to use the information in the question for the advantages and disadvantages
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    Why y'all *****ing yourself over one mark
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    (Original post by matt1997x)
    If you think about that pest control question, it wasn't very good at all. In my opinion, it is Biological but I answered Chemical, didnt even cross my mind. As well as that, on one of the bullet points it said something along the lines of 'it kills SUSCEPTIBLE INSECTS', suggesting that it affects more than just the caterpillar. But then in the last bullet point it said 'it does not harm any other species'. It's stuff like that that really annoys me. We've all worked our backsides off this year despite your intelligence, and the fact they give you an exam that attempts to trick you into saying one thing is a joke. I read something before that 45% is recall, 45% is application, and 10% is synoptic. This exam was 20% synoptic, 50% application and 30% recall. It really annoys me that my chances of doing the career I want are hindered by some clever examiner choosing these types of questions. I don't feel confident for BY5 at all, I needed an A in BY4 so I could manage a D in BY5. That's not going to happen, and I bet we're shovelled the exact same sh** when we come to sit BY5. Exams boards are a joke man.
    Feel you like ****. For me this wasn't that bad but I'm in the same boat for the CHEM 4 exam. It's screwed my chances of uni, I don't even know if I managed 15/100 marks. I've been putting in 9 hour days for the last 4 months and for what? For one exam to be the difference between uni and no uni. **** it
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    Ive just realised that for the nitrogen 10 marker it said some thing like name 'describe the biochemical processes that happen during the nitrogen cycle' i explained the entire nitrogen cycle but i didnt say things like "this biochemical process is denitrification" or "this is process is ammonification" I just said it as nitrates are denitrified to their products and decomposer form ammonium ions. Does this mean i will lose loads of marks for the esaay? Omg im panicing right now.
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    (Original post by Spwoosh)
    Ive just realised that for the nitrogen 10 marker it said some thing like name 'describe the biochemical processes that happen during the nitrogen cycle' i explained the entire nitrogen cycle but i didnt say things like "this biochemical process is denitrification" or "this is process is ammonification" I just said it as nitrates are denitrified to their products and decomposer form ammonium ions. Does this mean i will lose loads of marks for the esaay? Omg im panicing right now.
    The january 2010 BY4 paper 10 marker was essentially the same. This was the mark scheme: so no, maybe 3 marks of the possible ones will be down to what you left out
    A. Decomposition / putrefaction; B. Recycling nutrients; C. Breakdown of organic materials into inorganic / suitable e.g.; D. Nitrifying bacteria; E. Nitrosomonas, Nitrobacter; F. ammonium compounds to nitrites; G. nitrites to nitrates; H. ammonium compounds to nitrates if no F/G; I. Nitrogen fixing bacteria; J. atmospheric nitrogen converted into organic nitrogen / e.g.; K. free living azotobacter; L. rhizobium; M. root nodules of (legumes); N denitrification [Max 8] O. encourage aerobic conditions (to stop denitrifyers) / ploughing; P drainage for aerobic conditions to stop denitrifyers; Q grow leguminous crops / add organic waste products / manure / urea etc;[Max 2]
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    does anyone have a previous markscheme for the cyclic/noncyclic 10 marker???
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    (Original post by Tamsyng)
    does anyone have a previous markscheme for the cyclic/noncyclic 10 marker???
    Name:  image.png
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Size:  209.6 KB This one didn't specify about non-cyclic but briefly mentions it
 
 
 
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