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AQA BIOL2~3rd June 2013~AS Biology (Now Closed)

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Yeah I think it's 1 mark for filter paper and another for anything like "without lipid" or "water"

and for second bit should get 2 marks for that but maybe 1 because it doesn't help to move them, they line up on the equator themselves.
Also could have said it keeps sister chromatids together

Okay thank you and yeah I think I should get two maybe 1 but I think there were probably 3 marking points available

-centromere holds two sister chromatids together
-spindle fibres attach so to centromere so chromosomes move to equator
-centromere divide
But yeah maybe get 1 but thanks anyway!

Reply 3961

VigneshSB

For the missing amino acid, I think they would allow deletion of three bases coding for amino acid, because 1) We were'nt taught the unit 5 stuff about frame shifts, and 2) If the 3 bases were on the end of a chromosome, deletion would not change any other amino acids.

Reply 3962

Secret.

Original post by Scienceisgood

I put cytochrome c is a protein which is made of amino acids.
Amino acids are made/coded for via the triplet code on the DNA sequence.
Similar DNA sequences sequence the amino acids which code for cytochrome c. :rolleyes:

but haemoglobin is also a protein made from amino acid sequences isn't it? I thought it is becasue most organisms carry out respiration so most organisms will have cytochrome c

Original post by SarahEA

What did people put for the number of times the spiracles opened in a minute ???

Reply 3963

elgrace

Original post by MrMikeEsq

In the one saying why is cytochrome better than haemoglobin, what did you put?
I was gonna say they all have it but then again wouldnt they all have haemoglobin?

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This is what I thought too. I said different species have different haemoglobins as they have different DNA sequences but this is probably wrong.

Reply 3964

Scienceisgood

Original post by LaLady

And the opening of spiracles
It opened at 4-6 then 16-18???
so 16-4 = 12
60/12 = 5?

It was 6.
8 seconds to prepare opening spiracles and a further 2 seconds open.
totalling 10.

60/10 = 6

Reply 3965

laithmo96

Do we lose marks for not rounding up? The percentage increase question and the index of diversity

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Reply 3966

MrMikeEsq

Original post by Scienceisgood

But haemoglobin is made from amino acids too

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Reply 3967

Scienceisgood

Original post by Secret.

but haemoglobin is also a protein made from amino acid sequences isn't it? I thought it is becasue most organisms carry out respiration so most organisms will have cytochrome c

That's what I put but I crossed it out. :frown:

*Face laptop*

Reply 3968

SarahEA

Original post by DrFantastic

I'm afraid to say that the textbook is wrong.

Small organisms have a large surface area to volume ratio.

Never trust Nelson Thornes! The amount of mistakes they make in the Chemistry A2 Textbook is beyond belief.

I don't think it's wrong , it's just that think of an insect like a beetle or something , they don't have a very large surface area to volume ratio because they have like a waxy layer .... That's the way I think the publishers meant to say ... I know very confusing :/

Reply 3969

chloflorence

Original post by DrFantastic

Requoting so people can see this :smile:

I got quite a few of these answers. Was actually dreading reading this but it seems that I got a few right so I'm a bit more confident!

How did everyone find it? I think it was a tricky but a fair paper :smile:

Whilst doing it, I hated it. Honestly the worst exam of my life and I take Physics too. With that being said, after looking at this unofficial mark scheme I'm a little more confident but not enough to think I did that great on! :frown:

Reply 3970

nerd1

Original post by Scienceisgood

That's what I put but I crossed it out. :frown:

*Face laptop*

I wrote cytocrome c is present in all eukaryotes

Reply 3971

LaLady

The amount of stupid mistakes i made in this paper is unbelievable.
Would i still get the mark for the hierrarchy question I put: 'group within group' i forgot to put an 's'. Probablys because i lack of sleep didnt sleep till like 5am lol

Reply 3972

Liam2404

Original post by LaLady

Yes they'll know what you mean dont worry :smile:

Reply 3973

Scienceisgood

Original post by nerd1

I wrote cytocrome c is present in all eukaryotes

That's the first mistake (possibly second given I said control temperature in what would you control in snake experiment).

Reply 3974

VigneshSB

UNIT 5 A2 Students gonna HATE THIS! Just got conformation from my uncle who is a doctor! In the missing amino acid question, the Deletion of 3 bases is perfectly plausible, and NO FRAME SHIFT occurs because all other triplets remain intact. So all you people from the year above, GO AND LEARN YOUR UNIT 5 MORE! HAha! :P

Reply 3975

Shaadi Baba

Original post by VigneshSB

How do you know 'your uncle who is a doctor' (lol heard that one before) isn't wrong?

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Reply 3976

Ddiamondsea

Deletion is mentioned in unit two text books very briefly when talking about mutation

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Reply 3977

SarahEA

Original post by DrFantastic

Damn I think I put 5 because I did 60/12 which is 5 but then I also put down 60/10=6 , so might get a mark lol !

Reply 3978

chelley2

What happened to;
tissue fluid ,DNA hybridisation ,blood vessels and the other half of the spec.If I get anything higher than D it's a miracle

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Reply 3979

Liam2404

Guys on the question about fetal heamoglobin i put
-it has a higher affinity for oxygen
-so it onloads more oxygen at lower partial pressures
-so it can compete with the mothers haemoglobin to gain enough oxygen
-oxygen supply is lower in the womb (than in the air)

Would i get 1/2 for this for talking about onloading at lower partial pressures? :smile:

i think ive lost the second mark for not talking about respiration for growth :c nevermindd