IAL 2018 biology unit 2

Osh0711

Is it just me or was the paper hard :frown:

Reply 1

ItsFrznn

I really liked it, what did you find hard? Which questions?

Reply 2

Osh0711

Original post by ItsFrznn

I really liked it, what did you find hard? Which questions?

How did you figure out the base sequence? From the percentage distance.

Reply 3

The Korean girl

Original post by Osh0711

How did you figure out the base sequence? From the percentage distance.

I got stuck in that question though hahah
my answer was A C D B ,, with 3 boxes inbetween each bases... UGhhh somebody pls tell me the answer bf I get cancer :2in1:

,..
Oh and btw for the stone question, the pangolia (?) has no teeth, it ingest stones to tear the food it consumes,, basically it act like the teeth!!

Reply 4

Mughundhun SL

Hey guys,
This is Mughundhun SL from India. I wrote my Biology Unit 2 today and the paper was sort of easy except for a very few sub questions. If you want anything related to advice and tips on improving your personal self all you gotta is just contact me and i will reply to all of your questions. And by the way what was the base sequence that was worth 3 marks? Would really appreciate an answer
Thank you

Reply 5

Osh0711

Original post by The Korean girl

I got stuck in that question though hahah
my answer was A C D B ,, with 3 boxes inbetween each bases... UGhhh somebody pls tell me the answer bf I get cancer :2in1:

,..

Oh and btw for the stone question, the pangolia (?) has no teeth, it ingest stones to tear the food it consumes,, basically it act like the teeth!!

Ohhh yesss it makes so much sense now. It doesn’t have teeth. I didn’t think of it that way :/

Reply 6

Bsjz

Guys what do you think the curve of A would be?? I actually found it pretty hard

(edited 6 years ago)

Reply 7

Osh0711

Original post by Bsjz

Guys what do you think the curve of A would be?? I actually found it pretty hard

Which curve?

Reply 8

ThatGuy26

For the question asking us to plan an investigation to compare the rate of mitosis in cancer and normal cells, I basically wrote down the procedure for the root tip squash experiment which I'm sure we're all familiar with. I wrote that we should use two samples of onion root meristem cells - one normal and one cancerous.

Here's the thing, though - plant cells cannot get cancer. This fact was only made apparent to me after the exam. My teacher says I should have mentioned using human skin cells instead, but the procedure for the experiment would otherwise be similar.

Will I still get marks for describing the procedure correctly, or will I not gain any marks at all because of the flawed premise of my experiment?

Reply 9

Osh0711

Original post by ThatGuy26

Oh :/ you should use two samples of human cells. One sample of cancer and one sample of healthy cells. And also the part where you add HCL to macerate the tissue should be excluded. Because HCL is used in root tip tissue to break the middle lamella. Since there’s no middle lamella in animal cells you should exclude that step. I don’t know whether they’ll give you marks for the rest of the answer. Since it was a * question they’ll be strict with their marking :/ lets hope they give marks for the rest of the points. Did you write about calculating the mitotic index between the healthy and cancer cells?

Reply 10

ThatGuy26

Original post by Osh0711

I know, I screwed up. I mentioned HCl and middle lamella because I thought we were working with root tip meristem cells. Since Edexcel supposedly doesn't practice negative marking, hopefully they'll just ignore my wrong points instead of penalising me for those.

- I mentioned using a stain (acetocarmine).
- I mentioned squashing the cells and further teasing them apart with a scalpel (not sure if still relevant with regards to human cells).
- I mentioned gently heating the slide to intensify the colour of the stain.
- And yes, I mentioned calculating and comparing mitotic index.

Not sure if I could still net myself a mark for [the idea of] comparing normal and cancerous cells even though I used the wrong cell type. That might be pushing it.