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Edexcel igcse biology may 2012 exam discussion

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I just sometimes get unnecessarily nervous about things but my answers turns out to be correct and it's hard to say without looking at the paper but I would say near ~110/120
you?

Same here, I have no clue without the paper in front of me. I would estimate 110 /120 as well but I'm not taking any chances, I have revised beer, milk, yoghurt etc in preparation for tomorrow. :smile:

Reply 521

Big-Daddy

Original post by Umackjiggles

I'm starting to think 105/120 is optimistic for that paper. :frown:

I really don't know ... I did far worse than in either of my mocks, and I didn't do that great in them either.

However, I hope I'm ready for tomorrow. :smile:

If I got 105/120 on that one and I get 50/60 in this one, I can be confident of an A*. And hopefully I'll get much higher in this one.

What do you think will come up? Beer rarely comes up, and it already has, and I don't think I've ever seen a question on yoghurt production ...

Reply 522

Clare2012

I think yoghurt production will come up too and maybe something about the phloem, placenta and maybe nitrogen cycle as they are on the spec but not come up too much.

I also think that transgenic animals/how to make transgenic thing with the restriction/ligase enzymes could potentially be a 5 or 6 marker.

But I really don't know...any more ideas???

Reply 523

Umackjiggles

Original post by Big-Daddy

I'm starting to think 105/120 is optimistic for that paper. :frown:

I really don't know ... I did far worse than in either of my mocks, and I didn't do that great in them either.

However, I hope I'm ready for tomorrow. :smile:

I am nearly 100% certain that GM will come up as will eutrophication. The comprehension question will be 11 marks, GM will be 6 and eutrophication will either be 3 or 6 depending on the length of the question. The other half of the paper will probably deal with the heart, germination possibly as it hasn't come up in recent papers and almost certainly the eye / nervous system.

Reply 524

Clare2012

Original post by sahajkaur

Yeah i guess it can be used for both. Good luck tomorrow!

You too!!

Reply 525

username967389

Does anyone know whether the A* boundary is dictated by a certain mark or by position in the country compared to others? Because that would mean an easy paper would mean a harder A* for me...

Reply 526

member963009

Original post by eebootwo

Does anyone know whether the A* boundary is dictated by a certain mark or by position in the country compared to others? Because that would mean an easy paper would mean a harder A* for me...

They take everyone's score and they give an A* to the highest scoring people. Only 20% of people who take the exam can get an A*

Reply 527

Umackjiggles

I think we should do an in-thread revision session where we each ask one question to another user who then answers and comes up with their own question, etc. What do you guys think?

yeah

Do it, you go first!

What changes occur in the eye when you focus on an object that is far away, assuming you were focussing on a nearby object previously?

Reply 531

Big-Daddy

Original post by Umackjiggles

Wow, how can you have guessed so many topics? The comprehension will be 11 marks? GM will 6? Presumably in one long question (a 6-marker) - what GM question could offer 6 marks?

And can you really ask questions about germination? I guess they could ask what the radicle, plumule and cotyledons are, or what conditions are needed (warmth, water and oxygen, right?) ...

Original post by sahajkaur

Do it, you go first!

I'd be happy to, but I'm not going to be on here consistently. :tongue:

(I actually have to revise.)

Reply 532

Big-Daddy

Original post by Umackjiggles

What changes occur in the eye when you focus on an object that is far away, assuming you were focussing on a nearby object previously?

SPEED answer:

The ciliary muscles relax and the suspensory ligaments contract; this causes the lens to be pulled thin, as light needs to focused increasingly less.

:biggrin:

Reply 533

Big-Daddy

My question:

Explain the process of GM to enhance a plant and give an example of this in real life. (6)

Reply 534

Umackjiggles

you use restriction endonucleases in order to isolate and extract the gene for resistance to cold temperatures(for example). You then use the same restriction endonucleases on the plasmid of the bacteria Agrobacterium. You then mix the two together and they stick together on account of their sticky-ends. You then add DNA Ligase in order to hold them permenantly together. You then add a solution contain the plasmid which acts as a vector and you pour it into a petri dish with leaves (explants) from the plant you want to modify. The explants should take up the plasmid thus creating a genetically modified plant with a resistance to cold temperatures thus increasing the expected yield of the crop.

Reply 535

aaa_aaa

Label the main parts of the brain. (5)

Reply 536

aaa_aaa

Btw, for the question about an example of biological control, did the example have to be specific or could you just say a predator?

Reply 537

aaa_aaa

One more thing, was there a q about ADH in the bio exam?? I can't remember it but my mate told me there was???!??

Reply 538

Umackjiggles

Original post by aaa_aaa

Label the main parts of the brain. (5)

Not on the syllabus :biggrin:

, also ADH was in the exam (they asked what effect it had on the body) and they wanted you to give a specific example for the biological control such as ladybirds in order to eliminate aphids.