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Edexcel igcse biology may 2012 exam discussion

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Reply 480
Original post by sahajkaur
YES! Thank you. Finally someone with a brain.

My syllabus had 2 'mock exams' at the end, and even they didn't ask to describe an experiment or anything. There were 3 experiments in the paper. The first one said 'state the dependent variable'. The second asked to give the temperature readings off the thermometers, and to draw a table with the measurements, and the 3rd said 'suggest a safety precaution'. I highly doubt another question asking to write out a specific experiment will come up again...?


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Reply 481
Original post by Clare2012
Evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation?????? Could anyone give me a few ideas as to what this is about. Thanks :smile:


It's stuff like people think it's immoral to clone animals for such selfish human purposes but on the other hand it would significantly improve the amount of donors available and animals can be genetically modified to carry human antigens meaning that they are less likely to be rejected. But the minus is that the organism (such as a transgenic pig) may carry hidden viruses in their DNA, may have a pathogen which does not affect them but is fatal to the recipient and also that immune-suppressant drugs given to the person will mean an increased likelihood of the pathogen reproducing and infecting the body. Hope my rant helped! :smile:

Original post by IGCSE
you would know that already ^^^ from theory but at the same time how would you know that the cause of the purple colour of hydrogen carbonate is due to the removal of an acidic gas (Co2) causing it to be alkaline and therefore purple?


Yeah so none of your experiment BS came up did it. Like I said common sense.
Reply 482
Describe simple controlled experiments to demonstrate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms...is this the thermos experiment???
Reply 483
Original post by Tazxx_xx
My syllabus had 2 'mock exams' at the end, and even they didn't ask to describe an experiment or anything. There were 3 experiments in the paper. The first one said 'state the dependent variable'. The second asked to give the temperature readings off the thermometers, and to draw a table with the measurements, and the 3rd said 'suggest a safety precaution'. I highly doubt another question asking to write out a specific experiment will come up again...?


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Yes same! We did two mocks and it's always like that so I find it very foolish that people are rote learning the experiments!
Original post by IGCSE
you would know that already ^^^ from theory but at the same time how would you know that the cause of the purple colour of hydrogen carbonate is due to the removal of an acidic gas (Co2) causing it to be alkaline and therefore purple?


I don't quite understand why it's purple but I could easily predict that the removal of CO2 causes the solution to be increasingly alkaline. And if I had studied the sodium hydrogen-carbonate indicator I would know the necessary colours.

But I didn't need to, because they were given. See? It's simple! Everything you don't know is given. The rest is basic biological knowledge. The only indicators you need to know are iodine (starch), Benedict's (glucose) and the biuret solution (protein).
Reply 485
Original post by sahajkaur
Yes same! We did two mocks and it's always like that so I find it very foolish that people are rote learning the experiments!


Yeah, it's just simple questions ABOUT the experiment. Common sense, that's all


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Reply 486
Original post by akhamba12
did anyone do igcse maths and igcse english too? confident about Bio tomorrow?


yes :smile:

Original post by Clare2012
Describe simple controlled experiments to demonstrate the evolution of carbon dioxide and heat from respiring seeds or other suitable living organisms...is this the thermos experiment???


You put seeds on a gauze in a test tube with hydrogencarbonate indicator and then test for colour change. And yes I did not need to rote learn experiments to know this! :smile:
Reply 487
Original post by Big-Daddy
I don't quite understand why it's purple but I could easily predict that the removal of CO2 causes the solution to be increasingly alkaline. And if I had studied the sodium hydrogen-carbonate indicator I would know the necessary colours.

But I didn't need to, because they were given. See? It's simple! Everything you don't know is given. The rest is basic biological knowledge. The only indicators you need to know are iodine (starch), Benedict's (glucose) and the biuret solution (protein).



Original post by Tazxx_xx
Yeah, it's just simple questions ABOUT the experiment. Common sense, that's all


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Thank you you two seriously! Glad I'm not the only one! ^_^ I would like your posts but TSR won't let me :frown:
Reply 488
Original post by sahajkaur
yes :smile:



You put seeds on a gauze in a test tube with hydrogencarbonate indicator and then test for colour change. And yes I did not need to rote learn experiments to know this! :smile:


Exactly. It's basic knowledge.


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Original post by sahajkaur
It's stuff like people think it's immoral to clone animals for such selfish human purposes but on the other hand it would significantly improve the amount of donors available and animals can be genetically modified to carry human antigens meaning that they are less likely to be rejected. But the minus is that the organism (such as a transgenic pig) may carry hidden viruses in their DNA, may have a pathogen which does not affect them but is fatal to the recipient and also that immune-suppressant drugs given to the person will mean an increased likelihood of the pathogen reproducing and infecting the body. Hope my rant helped! :smile:


Past papers appear to show a pro-cloning approach. The only point on this topic I've ever seen coming up in a past paper is that all cloned organs will possess the same characteristics (so if the original works and will not be rejected, none will be rejected and all will work) and people may not want to donate their organs.
Reply 490
your choice.....do whatever you please
Reply 491
All of you are so gassed! Fighting over exams on a forum...
Reply 492
everyone might already know this but the first question seems to be kinda passage based and you just gotta use the info from the passage and a bit of your own knowledge, i reckon there will be a 5 or 6 marker on something like cloning, GM, or maybe affects of smoking on the heart. Tbh i think we've had the majority of our experiment questions already in paper 1 because of the yeast experiment and the CORMS one...i don't think learning by rote will be useful at all
Reply 493
Original post by F H 95
All of you are so gassed! Fighting over exams on a forum...


easy bro
Reply 494
Original post by F H 95
All of you are so gassed! Fighting over exams on a forum...


Not really fighting. The poor girl was just trying to help. You don't need to learn experiments word-for-word. No one needs to make a big deal of it. If you want to waste the time on learning all those experiments- go for it. No one is stopping you.


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Reply 495
Original post by sahajkaur
yes :smile:



You put seeds on a gauze in a test tube with hydrogencarbonate indicator and then test for colour change. And yes I did not need to rote learn experiments to know this! :smile:


Oh I thought that was for investigating the effect of light on gas exchange?? But I guess they could be used for both experiments!!

Thanks!!
Reply 496
Original post by Clare2012
Oh I thought that was for investigating the effect of light on gas exchange?? But I guess they could be used for both experiments!!

Thanks!!


Yeah i guess it can be used for both. Good luck tomorrow!
Reply 497
Was there anything about the kidney/excretion in paper 1? Or will it come up tomorrow?


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Reply 498
Original post by Tazxx_xx
Was there anything about the kidney/excretion in paper 1? Or will it come up tomorrow?


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adh was briefly mentioned.
Reply 499
Original post by Tazxx_xx
Was there anything about the kidney/excretion in paper 1? Or will it come up tomorrow?


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There was just a little bit about Ultrafiltration if i remember correctly.

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