POST-MORTEM: AQA Additional Science Biology B2 (May 2013)

Oh yeah, I got 4 and 8, but surely the offspring will have 12 chromosomes?

Okay I'm jet going to try and recall what I wrote for Q8, what did you guys write?

8a) They duplicate.
8b) Something about having to replicate so that when the cell splits into two they are the same as the original?
8c) They may have been descendants from a common ancestor because Species B has double the number of chromosomes as Species A and because they can successfully interbreed.
8d) They can no longer interbreed because there may have been a mutation in the alleles or… idek

Totally messed up there.

Reply 22

CathRM26

Original post by Hgat

Oh yeah, I got 4 and 8, but surely the offspring will have 12 chromosomes?

Yeah I also put 12.

Reply 23

CathRM26

Original post by HugeBicepLAD

AQA just got dicked by the HugeBicepLAD but unfortunately or fortunately my huge biceps lead me to believe that the HEXA enzyme didnt work because the amino acids would have been coded differently so the protein would have been a different shape so the substrate would no longer fit into the active site thus my biceps.. I mean the enzyme would not work

Did everyone mention substrate and active site for the one about why a change in DNA would affect the enzyme ?

I didn't.

i just talked about how it wouldn't work cos DNA is made of four bases which work in threes and then these code for amino acids which are enzymes etc. And if the bases in Dna were changed then the enzyme would not work.

Reply 24

scottystreet

OP

Original post by HugeBicepLAD

For the numbers in the box the answers were 4 then 8 and the offspring would have 8 chromosomes in the body cell

Original post by Hgat

Oh yeah, I got 4 and 8, but surely the offspring will have 12 chromosomes?

Original post by CathRM26

Yeah I also put 12.

It would appear there are quite a few contradicting opinions on the matter... I got 8, due to some kind of irrational change of mind from my original answer of 12, but we'll see.
I'll try and find something solid on Google.

Reply 25

HugeBicepLAD

Question 1:
a) Xylem and phloem
b)Diffusion is the net movement of particles from an area of high concentration to an area of low concentration down its concentration gradient.
c)Oxygen

Reply 26

username937957

18

I hope it went quite well but I did Foundation so yeah.

Reply 27

HugeBicepLAD

Original post by scottystreet

It would appear there are quite a few contradicting opinions on the matter... I got 8, due to some kind of irrational change of mind from my original answer of 12, but we'll see.
I'll try and find something solid on Google.

I had 12 and 8 lined up but I recognized it could be 8 because only 8 matched up

Reply 28

techno-thriller

14

Ok so for q3 I wrote 7 and a half BUT WHY IS NOONE DISCUSSING THE Q WHERE IT SAID HOW MANY CHROMOSOMES DOES A PLANT HAVE. I WENT ON GOOGLE AND IT SAID DEPENDS ON THE TYPE OF PLANT???

Reply 29

HugeBicepLAD

Original post by CathRM26

Okay I'm jet going to try and recall what I wrote for Q8, what did you guys write?

8a) They duplicate.
8b) Something about having to replicate so that when the cell splits into two they are the same as the original?
8c) They may have been descendants from a common ancestor because Species B has double the number of chromosomes as Species A and because they can successfully interbreed.
8d) They can no longer interbreed because there may have been a mutation in the alleles or… idek

Totally messed up there.

for 8a) I wrote they have two because one from maternal and one from paternal, can anyone confirm the answer?

Reply 30

Hgat

5

Original post by techno-thriller

Ok so for q3 I wrote 7 and a half BUT WHY IS NOONE DISCUSSING THE Q WHERE IT SAID HOW MANY CHROMOSOMES DOES A PLANT HAVE. I WENT ON GOOGLE AND IT SAID DEPENDS ON THE TYPE OF PLANT???

You just had to count them, there were 8

Reply 31

scottystreet

OP

Original post by HugeBicepLAD

I had 12 and 8 lined up but I recognized it could be 8 because only 8 matched up

Just found some stuff about the Przewalski horse reproducing with the wild horse (http://www.ansi.okstate.edu/breeds/horses/przewalski/).
Gametes are 32 and 33. They reproduce to form offspring with 65 chromosomes. Therefore, the answer in the exam would have been 12.
DAMN. I got it wrong.

Reply 32

techno-thriller

14

Original post by Hgat

You just had to count them, there were 8

stupid me I wrote 46!

Reply 33

HugeBicepLAD

Original post by techno-thriller

Ok so for q3 I wrote 7 and a half BUT WHY IS NOONE DISCUSSING THE Q WHERE IT SAID HOW MANY CHROMOSOMES DOES A PLANT HAVE. I WENT ON GOOGLE AND IT SAID DEPENDS ON THE TYPE OF PLANT???

Its different for all plants, you just had to count them so 8 and 16 and then divide by two to get the amount in a gamete so 4 and 8

Reply 34

Hgat

5

Anyone doing biology next year? (I can't decide between biology and economics)

Reply 35

techno-thriller

14

Original post by Hgat

Anyone doing biology next year? (I can't decide between biology and economics)

hell no. I've just burnt the biology sectionod the book

Reply 36

scottystreet

OP

Original post by Hgat

Anyone doing biology next year? (I can't decide between biology and economics)

Don't do Biology. I know a guy who did Biology, and he regrets it. (Mind you, he also regrets taking Maths, so...)

Reply 37

CathRM26

Original post by Hgat

Anyone doing biology next year? (I can't decide between biology and economics)

yep unfortunately :frown:

damn I really needed an A* in this one. I did about 11 past papers but still found the exam difficult today - it was the one on transects which caught me out initially and then Question 8 I just totally blanked on.