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Upcoming Edexcel AS Biology: Unit 2 exam on 26 May 2011

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I'm annoyed that people thought it was quite easy, because the people in my year who found it easy were the ones who didn't revise so much, whereas I've spent so long on it and am really disappointed in myself

I just want to go into A2 with a high A (my coursework was 40/40 and my Jan exam for Unit 1 was 108/120 UMS) so I might have to re-take this paper next January and hope a better one comes up with stuff I'd actually revised!!!
do u think i would get a mark if i said golgi apparatus makes lysosomes?
Original post by heyadinzi
yeh so did i !! what other questions came up that were hard.. the telophase one was annoying !! what did u do for the crossing over one


I first literally swapped over the colours for the whole pieces that they pointed at
but then i thought hmmm maybe thats too easy, so rubbed out my shading up till the point they pointed at, so the left X was grey with half of its top right bit white, and the right X was white with its top half of the top left bit grey

if that makes sense haha
what did everyone else do for the crossing over Q???
Original post by britchick
I said 23,000 for that reason too, so it could be able to code for all proteins and to carry out all functions etc :smile:

For the Golgi Apparatus question:
- at least 3 convex sacs ranging from smallest to largest
- the largest sac is the sac facing the ER i.e. the smallest sac is where functions are last carried out and is closest to the membrane
- the smallest sac is more condense with enzymes, which might be visible with a stain
- i drew a labelled diagram in case my explanation didnt make sense XD

For the Golgi apparatus/rER question:
- the transcripted RNA comes through the nuclear pores and attaches to the ribosomes (proteins) on the rER's surface
- the protein and genetic information travel through the rER, taking its 3D-like structure along the way
- vesicles pinch off the ends of the rER containing the protein and genetic information
- vesicles travel through the cytoplasm to the ends of the G.A's sacs, where they fuse into
- enzymes in the G.A modify the protein along its journey
- this includes the idea that if certain proteins need to be a certain direction e.g. receptors, the protein is turned in a certin way so it can be facing the rigth direction
- vesicles pinch off the ends of the G.A and travel to fuse with the cell membrane so it can carry out either intercellular/extracellular functions

lool haha i drew a diagram too for this exact reason and then labelled it
Original post by godknowsprerna
what did u guys write about the endemism questions .. i wrote its in Area D cauz tht was the only area with a unique species o.O to other areas


YES that's what I did! Woohoo! A question I've seen I did right!
Original post by pakizrulez
do u think i would get a mark if i said golgi apparatus makes lysosomes?


Yes, you will.
For the bacteria questions, the awnser was evenly spread the bacteria all over the petri dish to create accurate results whilst using gloves.
Original post by Alakamind
For the bacteria questions, the awnser was evenly spread the bacteria all over the petri dish to create accurate results whilst using gloves.


I just said something like pour it in using gloves. Hopefully a mark for the gloves part.
Original post by Alakamind
For the bacteria questions, the awnser was evenly spread the bacteria all over the petri dish to create accurate results whilst using gloves.


Yeah, you melt the agar to a liquid form, add the bacteria, shake gently to disperse the bacteria evenly, then wait to solidify
Guys what did two labels did you circle on the egg cell question?

In an egg cell there are eight haploid cells. I believe you could have picked any two except polar nuclei (which are diploid collectively, they fuse with the haploid male gamete to make a triploid endosperm). So any combination of egg cell/synergid/antipodal right?
Original post by snow leopard
Guys what did two labels did you circle on the egg cell question?

In an egg cell there are eight haploid cells. I believe you could have picked any two except polar nuclei (which are diploid collectively, they fuse with the haploid male gamete to make a triploid endosperm). So any combination of egg cell/synergid/antipodal right?


This question was worded SO badly, "circle two of the labels of two haploid cells"
...WTH?

I drew a circle around one polar nuclei in the middle, and the bottom middle cell, because I know that's haploid as it fuses with one of the generative nuclei to become diploid.

Someone said they circled the label words i.e. "polar nuclei" and "antipodal", but I cricled the actual cells, is this wrong? :\
where does mitosis happen?....what did you cross ?
Original post by pakizrulez
where does mitosis happen?....what did you cross ?


I think I said stem cells. It was a guess
Original post by britchick
This question was worded SO badly, "circle two of the labels of two haploid cells"
...WTH?

I drew a circle around one polar nuclei in the middle, and the bottom middle cell, because I know that's haploid as it fuses with one of the generative nuclei to become diploid.

Someone said they circled the label words i.e. "polar nuclei" and "antipodal", but I cricled the actual cells, is this wrong? :\


No that someone is correct - it was labels! Sorry :s-smilie:

Tricky question nevertheless, you either had to have further knowledge that all eight cells are haploid in the embryo sac, or guess that it was antipodal or synergid given it couldn't be polar nuclei.
Original post by snow leopard
No that someone is correct - it was labels! Sorry :s-smilie:

Tricky question nevertheless, you either had to have further knowledge that all eight cells are haploid in the embryo sac, or guess that it was antipodal or synergid given it couldn't be polar nuclei.


Damn. I hate how I seem to have done so badly and everyone else found the paper quite nice :frown:
Original post by britchick
I think I said stem cells. It was a guess


lool sameeee :smile:
i like your thinking britchick haha:biggrin:
its similar to myn
Just a few answers that I can actually remember putting...
A and C for the highest species richeness and lowest respectively.
The prokaryotic cell showed a flagellum and I put the outer dashed area as a capsule however some people have told me it could have been a cell wall. :s-smilie:
I then labelled the ribosomes and circular DNA inside the cytoplasm for the other 2 marks.

There was also an adaptations question I seem to recall which I believe EVERYONE taking the exam should have got, it was behavioural therefore I think it was the one where they lie down in the heat of the sun (can't remember great detail).

I put 23,000 genes as none of them had differentiated and totipotenty is unspecialised and undifferentiated. (I'm probably wrong here).

With the allele question where it required shading I simple just swapped the point at where they cross over onto the other one. So on the new diagram I just didnt shade the little tip on the right and shaded the left top top on the right one. If that makes sense.

There was a lot of data questions and one of the stem cell questions through me completely :/.

Overall it was okay, could have been better, hopefully the grade boundaries are low and that I got a C :smile: .
Original post by britchick
Damn. I hate how I seem to have done so badly and everyone else found the paper quite nice :frown:


I'll be honest in that it was very easy in comparison to previous years, especially the lack of irrelevant and complex graphs - we got a bar chart with the mineral ions were we just had to look for the highest mass (B had highest mag and calcium right?) and throughout were very simple statistics.

Grade boundaries usually always 60 for A, so just remember that you can lose 20 and still get A :smile:
Reply 138
hey guys how many marks was the labelling the haplod thing again??? i put the specie for endemism for A?? i was not sure?? but did you put for the gihest c?? and lowest D i dont remember?
Original post by godknowsprerna
oh my god o_o you are right o_o chemical signals turn the genes on which differentiates it :/ tht means to start with all the genes are off :/ ughhhh how stupid of me :frown:


so what is the answeer then? 23000 or 11000?

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