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AQA AS-Level Biology Unit 2 [Unofficial Markscheme]

Kudos to mickel_w who posted this on the AQA BIOL2 original thread, correct any mistakes and add whatever is missing:
EDIT: I WILL CORRECT EVERYTHING WHEN I GET A COPY OF THE QUESTIONS

1.a Coronary artery transports blood to heart muscle cells providing them with glucose and o2 for respiration allowing them to contract

b.Blood vessels A H E

c. Aorta has a bigger elastic layer, highest pressure exerted out of all vessels, elastic layer stretches and recoils at systole/diastole

2.a.Female lizards wider range, higher mean length

b.Lower plants diversity results in fewer habitats/niches/food sources, reduces insects and therefore lizard species diversity(Dont remember the order or numbers of questions sorry so ill just list what i remember)-

cellulose and starch differences: 1. Starch made from alpha glucose, cellulose beta2. No microfibrils in starch-similarities: 1. Both polysaccharides made from identical repeating monomers2. Both contaon glycosidic bonds

Adaptations of cells: sieve cell- large vacoule allows fast rate of mass flow, little resistance (probs wrong)Helper/companion cells: many mitochondria, produce lots of ATP used for active transport of sugars

Crickets questions:Courtship behaviour causes: -stimulates release of gametes-allows for identification of same species partners-identifies fertile/sexually mature partners

Place the male with both wings with the same females, record percentage showing courtship after song, compare values to recorded song

Dna q: humans and grasshoppers may have similar & of bases but different sequences resulting in different codons coding for different amino acids hence different proteinsb.

Viral dna single strand, as no base pairing due to different %s of c+g and a+t

Differences bacterial and human dna: bacterial circular, as plasmidBacterial not associated with proteins

Genetic bottleneck question: small population, low genetic diversity/small gene pool, inbreeding increases frequency of faulty allele as it ispassed onfo offspring

Ratio 32:1 (to all of you arguing yes, it was more frequent in the small population but the population of america was much, muchh greater so overall more people are colour blind in USA)

Classification:- no overlaps between groups therefore it is a hierarchy

6-marker:
-mutation is a change in specific dna base sequence, affecting at least one codon

-this changes the specific amino acid sequence-resulting in a different primary polypeptide shape

-therefore different secondary shape as hydrogen bonds form between different amino acids and different places in the chain-different tertiary shape of enzyme-alters shape of active site, no longer complementary to substrate

-no e-s complexes formed
(edited 8 years ago)

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Reply 1
Avatar for 1144297
1144297
9
Original post by asian.mikehunt
]b.Blood vessels A H E



I thought it would be AHF because F was on the side of the aorta so would be the renal artery - E was on the same side as A (It went AB, CD, EF) so would be renal vein?




1.

EDIT: Apparently I dun goofed, and the ones I put were AHE as other people are saying. Apparently when I was remembering it I thought it was the other way around.

(edited 8 years ago)
Original post by ThatPerson2
I thought it would be AHF because F was on the side of the aorta so would be the renal artery - E was on the same side as A (It went AB, CD, EF) so would be renal vein?

I've changed it to your answer since it sounds more reasonable :smile:
Reply 3
Avatar for 1144297
1144297
9
Original post by asian.mikehunt
I've changed it to your answer since it sounds more reasonable :smile:


Good to hear, thanks :biggrin:
Reply 4
Avatar for A9M4D
A9M4D
8
For the 4 marker on mitiosis, you AREN'T REALLY SUPPOSED TO DESCRIBE THE STAGES fully. What you do do is explain how the ddaughter cells are identical = stuff like: chromosome no. stays the same throughout, no independent segregation nor crossing over so no genetic variation. Then you talk a little about the stages (i.e. interposer = DNA rep and cytonkenisis = two new cells formed).
Original post by ThatPerson2
Good to hear, thanks :biggrin:


I said it was A D E, as the hepatic portal vein is between the intestine and liver
Reply 6
Avatar for sunny69
sunny69
2
could you put that there was synchronised mating for the courtship Q
Reply 7
Avatar for mickel_w
mickel_w
9
Original post by asian.mikehunt
Kudos to the guy who posted this on the AQA BIOL2 original thread, correct any mistakes and add whatever is missing:


Lol, it was definitely AHE. (I wrote this ahah)
Reply 8
Avatar for Shuerer
Shuerer
1
Original post by CMooreFalcons
I said it was A D E, as the hepatic portal vein is between the intestine and liver


Yes you are right, what did you put for question 9, to do with oestrogen?

Also grade boundaries anyone?
Reply 9
Avatar for NourSamy
NourSamy
1
Are there any other qs?x
Reply 10
Avatar for Shuerer
Shuerer
1
Yh, the geezers left out everything after question 8a)
Reply 11
Avatar for corpeal
corpeal
9
I put the renal artery as the one moving out of the kidney, was that correct? I can't remember which letter it was.

It was the bottom left one
Original post by Shuerer
Yes you are right, what did you put for question 9, to do with oestrogen?

Also grade boundaries anyone?


My guess:
A = 55
B = 50
C =45
D =40
E =35

They'll be around about those values. The whole paper was out of 85.
Reply 13
Avatar for Shuerer
Shuerer
1
Nah 60 for an A surely?
Original post by A9M4D
For the 4 marker on mitiosis, you AREN'T REALLY SUPPOSED TO DESCRIBE THE STAGES fully. What you do do is explain how the ddaughter cells are identical = stuff like: chromosome no. stays the same throughout, no independent segregation nor crossing over so no genetic variation. Then you talk a little about the stages (i.e. interposer = DNA rep and cytonkenisis = two new cells formed).

I swear it was talking about interphase though! didn't it?
I just spoke about interphase :banghead:
What did u guys put for the 5 marker?? I put No, then i said although; and after i said although i put arguments for yes.
Original post by NourSamy
Are there any other qs?x
OP left out questions as he/she could not remember them. Sorry
Original post by Shuerer
Nah 60 for an A surely?

I'm not sure, just guessing :dontknow:
Original post by sunny69
could you put that there was synchronised mating for the courtship Q


yeah pretty sure you can :smile:
Original post by Banteramos
I swear it was talking about interphase though! didn't it?
I just spoke about interphase :banghead:


It said how interphase and mitosis lead to genetically identical cells

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