IAL Biology Unit 2 January 2018

What are your thoughts on this paper guys

Reply 1

Original post by newyorkfries

What are your thoughts on this paper guys

It was okay. What was the answer for when does random assortment happen. It was an MCQ

Reply 2

I'm gonna try to remember most questions as possible
*How many ants eaten per year? I got 31025000
*When does crossing over happen? I put prophase 1
*Fill in BCD? I put D close to A, then B further away and C after that (A D B C)
*Use of ingesting stones? I have no idea

Reply 3

Original post by hami_2000

I'm gonna try to remember most questions as possible
*How many ants eaten per year? I got 31025000
*When does crossing over happen? I put prophase 1
*Fill in BCD? I put D close to A, then B further away and C after that (A D B C)
*Use of ingesting stones? I have no idea

The stones ingested by the pangolin build up in its stomach and act as a form of mechanical digestion by grinding down the insects that the pangolin eats. Basically, they perform the function of teeth, compensating for the fact that the pangolin is toothless. Chickens swallow pebbles for the same reason.

Now, I have a query for you. I asked this on another thread but I haven't gotten any replies yet.

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 4

You'll still get marks I think for the rest of the procedure. But I wrote we should use one cancerous piece of tissue and one normal piece of tissue. I didn't specify where it comes from. Are you sure we have to specify?

Reply 5

Original post by hami_2000

You'll still get marks I think for the rest of the procedure. But I wrote we should use one cancerous piece of tissue and one normal piece of tissue. I didn't specify where it comes from. Are you sure we have to specify?

I don't think so, no. I just wanted to be thorough, but it looks like I may have done myself more harm than good.

Does Edexcel practice negative marking, ie. do they take away a mark for a wrong point given? Or will they just ignore it and give me marks for whichever points I got correct?

Reply 6

Original post by ThatGuy26

I don't think so, no. I just wanted to be thorough, but it looks like I may have done myself more harm than good.

Does Edexcel practice negative marking, ie. do they take away a mark for a wrong point given? Or will they just ignore it and give me marks for whichever points I got correct?

They'll just ignore it. They never take away marks for wrong points made

Reply 7

Original post by hami_2000

They'll just ignore it. They never take away marks for wrong points made

Yeah, that's what I've been told as well. The only exception to this is if you make a wrong point that directly contradicts a correct point that you made.

Thanks for the reassurance.

Reply 8

Original post by ThatGuy26

Yeah, that's what I've been told as well. The only exception to this is if you make a wrong point that directly contradicts a correct point that you made.

Thanks for the reassurance.

Btw what did you put for when random assortment happen. the MCQ

Reply 9

Original post by hami_2000

Btw what did you put for when random assortment happen. the MCQ

Metaphase I is the correct answer, I believe. Crossing over between non-sister homologous chromosomes takes place during Prophase I. The next phase, Metaphase I, is when the chromosomes line up on the equatorial plate. That is when independent assortment occurs, as the chromosomes can either be arranged as such:

C1 | C2

or like this:

C2 | C1

where C1 and C2 are a homologous pair of chromosomes.

Reply 10

Hridita Bal

There was this question which asked to name two factors that increase biodiversity and two factors that decrease it. What did you put in that?

Reply 11

Canwave28

6

Original post by ThatGuy26

Metaphase I is the correct answer, I believe. Crossing over between non-sister homologous chromosomes takes place during Prophase I. The next phase, Metaphase I, is when the chromosomes line up on the equatorial plate. That is when independent assortment occurs, as the chromosomes can either be arranged as such:

C1 | C2

or like this:

C2 | C1

where C1 and C2 are a homologous pair of chromosomes.

Were you guys ever taught this? When I asked my teacher she said that Edexcel specifically asks them not to teach the metaphase 1, 2 and anaphase 1, 2 etc in meiosis 2. It's not in our syllabus!

Plus the question didn't give any context for us to answer based upon that....

Reply 12

Canwave28

6

Original post by Hridita Bal

There was this question which asked to name two factors that increase biodiversity and two factors that decrease it. What did you put in that?

I'm a little worried for this one. What did you put for it???

Reply 13

Original post by Canwave28

Were you guys ever taught this? When I asked my teacher she said that Edexcel specifically asks them not to teach the metaphase 1, 2 and anaphase 1, 2 etc in meiosis 2. It's not in our syllabus!

Plus the question didn't give any context for us to answer based upon that....

That's weird. The textbook we used covered the entire process of meiosis in extensive detail, and my teacher definitely did teach it.

Reply 14

Original post by Hridita Bal

There was this question which asked to name two factors that increase biodiversity and two factors that decrease it. What did you put in that?

Increase:
- New species migrating into the habitat (species richness)
- Mutation resulting in new alleles within the gene pool of a species (genetic variation)

Decrease:
- Poaching
- Habitat loss

Reply 15

newyorkfries

OP

Original post by canwave28

were you guys ever taught this? When i asked my teacher she said that edexcel specifically asks them not to teach the metaphase 1, 2 and anaphase 1, 2 etc in meiosis 2. It's not in our syllabus!

Plus the question didn't give any context for us to answer based upon that....

i do agree with this.

Reply 16

Hridita Bal

Well, for increase I gave -
Captive breeding programme and re introducing them into wild
And decrease in pollution
For decrease I gave -
Habitat loss
Increased risk of disease
Are they okay?😞

Reply 17

Canwave28

6

Original post by Hridita Bal

Well, for increase I gave -
Captive breeding programme and re introducing them into wild
And decrease in pollution
For decrease I gave -
Habitat loss
Increased risk of disease
Are they okay?😞

They all seem plausible. I wrote:
for increase:
-Nature reserves.
-reforestation
for decrease:
-deforestation
-hunting/ poaching

I am terrified too!😞😞
I hope they have a LOOONNGG list of answers including all these!

Reply 18

Hridita Bal