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    We learn that batch culture is used to produce secondary metabolites.

    However, yeast fermentation is a batch culture process. Ethanol is a primary metabolite however. So the question is, why do we use batch culture to produce ethanol using yeast? Why not continuous culture? Ethanol would still be produced using continuous culture because ethanol is a primary metabolite. June 2014 F215 examiners report states that it is a batch culture process. WHY????
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    Are we supposed to know what RNA interference is? Its not anywhere in the spec but it keeps popping up in past papers? Not sure oif this is just old spec though...
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    (Original post by jeslene)
    Any predictions on what questions will come up for unit 4 this year?
    it's almost pointless trying to predict with ocr. they can literally throw anything at you. resat f211 this year and they started talking about endosymbiont theory which is in f214 so there you have it! someone even made a predicted paper for f211 and none of it came up lol, just gotta revise it all i guess. What I did for f211 was go through every past paper and write down the spec points that had come up, so I could deduce which spec points had not come up. They haven't tested slightly less than half the spec points since June 2009, so it was impossible to predict what was going to come up!
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    (Original post by Hilton184)
    We learn that batch culture is used to produce secondary metabolites.

    However, yeast fermentation is a batch culture process. Ethanol is a primary metabolite however. So the question is, why do we use batch culture to produce ethanol using yeast? Why not continuous culture? Ethanol would still be produced using continuous culture because ethanol is a primary metabolite. June 2014 F215 examiners report states that it is a batch culture process. WHY????
    How is ethanol a primary metabolite for yeast? It's only produced when oxygen isn't available, hence anaerobic respiration, which therefore makes it a secondary metabolite. When oxygen is available, yeast undergoes normal respiration like most other organisms
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    Good definition for linkage...
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    (Original post by domcandrews)
    it's almost pointless trying to predict with ocr. they can literally throw anything at you. resat f211 this year and they started talking about endosymbiont theory which is in f214 so there you have it! someone even made a predicted paper for f211 and none of it came up lol, just gotta revise it all i guess. What I did for f211 was go through every past paper and write down the spec points that had come up, so I could deduce which spec points had not come up. They haven't tested slightly less than half the spec points since June 2009, so it was impossible to predict what was going to come up!
    Endosymbiosis? That's not in the spec for f214 nor is it in either of my books
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    (Original post by ChoccyPhilly)
    How is ethanol a primary metabolite for yeast? It's only produced when oxygen isn't available, hence anaerobic respiration, which therefore makes it a secondary metabolite. When oxygen is available, yeast undergoes normal respiration like most other organisms
    Ethanol is a primary metabolite. One of the questions in the 2014 F215 exam asks why is ethanol considered a primary metabolite.

    Also, some species of yeast prefer to use anaerobic respiration even in aerobic conditions.


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    Can somebody explain phylogenetic species concept please ?


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    is anyone who is doing the A2 exams and not retaking AS, what stuff are you going to try and revisit from AS to prepare for the A2 exams. i remmeber on one past paper they had a whole question where you needed knowledge from As about the diseases etc?
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    why waste time learning f215 chaper 4 when it almost certainly will only be 10 marks or less. Surely better to secure a higher mark in the others?
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    (Original post by AsianBeauty)
    Can somebody explain phylogenetic species concept please ?


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    So contrasting the two, the biological species concept is the traditional concept of species - a group of similar organisms able to interbreed to produce fertile offspring. However the biological species concept fails to classify species like bacteria that reproduce asexually - as these species do not interbreed.

    So this is why the phylogenetic species concept is better sometimes. This states that a species is an group of organisms similar in morphology, embryology etc, that are members of the same monophyletic group.


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    (Original post by Hilton184)
    So contrasting the two, the biological species concept is the traditional concept of species - a group of similar organisms able to interbreed to produce fertile offspring. However the biological species concept fails to classify species like bacteria that reproduce asexually - as these species do not interbreed.

    So this is why the phylogenetic species concept is better sometimes. This states that a species is an group of organisms similar in morphology, embryology etc, that are members of the same monophyletic group.


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    Thank you ! Do you need to know about cladistics ?


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    (Original post by maisie__x)
    Endosymbiosis? That's not in the spec for f214 nor is it in either of my books
    it's an application of knowledge for the mitochondria in respiration section for f214! I remember my teacher giving us a whole booklet on the theory, as extra reading around the course. didn't have the time to read over it yet, was planning to read over all the booklets she gave us extra for the f214 and f215 exam. turns out they chucked it in to the f211 exam!
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    (Original post by AsianBeauty)
    Thank you ! Do you need to know about cladistics ?


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    No problem:-) and no I don't think so. The official textbook throws extra stuff like that in for some odd reason even though it's not in the spec.


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    (Original post by normalman)
    why waste time learning f215 chaper 4 when it almost certainly will only be 10 marks or less. Surely better to secure a higher mark in the others?
    lol true, but what happens if half the paper is on chapter 4 ahaha? all that brain and behaviour stuff could be a big topic if they wanted to.
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    (Original post by domcandrews)
    it's an application of knowledge for the mitochondria in respiration section for f214! I remember my teacher giving us a whole booklet on the theory, as extra reading around the course. didn't have the time to read over it yet, was planning to read over all the booklets she gave us extra for the f214 and f215 exam. turns out they chucked it in to the f211 exam!
    Okay, thank you If i just read over it do you think that will be okay? I'm guessing its for possible suggest questions?
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    (Original post by maisie__x)
    Okay, thank you If i just read over it do you think that will be okay? I'm guessing its for possible suggest questions?
    lol yeah that was my plan for f214 and f215 but not for f211 aha! so i was slightly surprised to see it in there, but i got it in the end, but only because i remebered it vaguely from f214!
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    hi there guys, can someone explain to me why liposomes are inefficient vectors.
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    (Original post by kell123)
    hi there guys, can someone explain to me why liposomes are inefficient vectors.
    we have to know that ?! I just use Viruses on Qs about gene therapy
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    June 10 F214 Q5aiii - when is the membrane most permeable to potassium ions.

    Apparently the answer is D. But the potassium ion channels open at C, so this is when the concentration gradient will be greatest, so surely this is when the membrane is most permeable to potassium ions no? I don't understand how it could possibly be half way into re-polarisation, when clearly by this point there is a much lower electrochemical gradient.
 
 
 
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