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AQA BIOL2 Biology Unit 2 Exam - 26th May 2011

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Not the chromosomes, the chromatids have separated.

This is a definition of chromatid: Either of the two strands joined together by a single centromere, formed from the duplication of the chromosome during the early stages of cell division and then separate to become individual chromosome during the late stages of cell division.

So one chromosome forms two chromatids which are separated to form one chromosome so the number of chromosomes is unchanged.

It has half the mass of DNA because the DNA is doubled and shared between the two cells.

I'm sorry if I'm confusing you even further. :colondollar:

Thank you.
I think i understand.. i need more practice. I thought i was ok :'( panic!!

Reply 621

F1's Finest

Original post by parallal

Does anyone think we'll have questions on circulation?

yes.

its related to the blood though.

The Left Ventricle and Right Ventricle pump the same volume of blood with each beat of the heart. Explain why this occurs. 2 marks

Answer:
All blood leaving the right side of the heart returns to the left. (1)
Internal volume of heart same on both sides (1)

thats the only question that vaguely relates to circulation, someone please confirm this thanks.

Reply 622

jbop

Original post by oHellno

Jan 2011 is horrific.

Oh yeah I've got that one here, we did it as a mock in class last week. My worst nightmare, transpiration and cell division. I really just can't get into the june paper, even the mark scheme looks like it's from a different paper! I'm abandoning my efforts.

Reply 623

lolo-x

Original post by jbop

don't give up! I just did June 2010, and if you do it with the mark scheme next to you then its quite a good revision resource, the key thing with these exams is knowing what the question is looking for, thats my problem coz the questions seem quite ambiguous sometimes :/

Reply 624

kingsmod1

Original post by Stratos

I got a d last time >__>. But yeah I'm revising properly now last time I actually forgot I had the exam and didn't revise a single minute.

not much u can revise, just remmber the booj, have a gd exam technique on data and stuff, the rest is really experience and stuff. practice paper etc.

Reply 625

parallal

Original post by James A

Thanks. There was also a question in the June 2009 paper about circulation (the first question) and in the specimen paper.

They weren't too bad but I hope it doesn't get any more complicated than those kinds of questions though.

Reply 626

kingsmod1

jan 11 bio 2 was a disgusting paper lol

Reply 627

jbop

Original post by lolo-x

I'm the same, I waffle and think, yeahh that sounds reasonable. But if you miss out a key word that's your mark gone. I'm doing just that now, going through it with the mark scheme but it's all over the place! Have you seen 5cii and 5di? The answers are shocking! I had to check I was looking at the right mark scheme!

Reply 628

ScienceGeek3

Which of these topics do you guys think will have more questions on?

gas exchange in fish vs gas exchange in insects
apoplast pathway vs symplastic pathway
root pressure vs cohesion tension theory
meiosis vs mitosis
DNA hybridisation vs immunological comparisons of proteins

Just wanted to know as to what guesses people have for tomorrows paper!

Reply 629

Is it a bird!?

Anyone have any tips on how to answer these questions? :biggrin:

Questions in the exam I mean, I don't get what they're asking for and always say the wrong stuff.

Reply 630

oHellno

Original post by kingsmod1

jan 11 bio 2 was a disgusting paper lol

That long question on shrimps was a joke, I had to stop.

Reply 631

TlanTlan

Think an early night is in order tonight. Need to be well rested for max concentration so i can see through aqa's bull**** tommorow on this exam.

Reply 632

F1's Finest

Original post by parallal

yeah, well ideally i would like a paper that hasnt got a lot of how science works questions, i prefer just knowledge based questions, im aiming for an A to push my grade to an overall A

Reply 633

Kandy_Kain_94

Can someone explain these please:

Transpiration Pull

Root Pressure

cohesion-tension hypothesis

Thanks

Reply 634

TlanTlan

My offer is 3 B's (i'm an a2 student) so hopefully i can get an A in this and never have to do it again. Biology is an interesting subject but AQA just make it horrifyingly painful.

Reply 635

lolo-x

Original post by jbop

yeah, the questions are really badly worded.but hey, what can we do! just gonna have to learn to try and read the examiner's mind :/

Reply 636

Patchey1000

Original post by Kandy_Kain_94

Can someone explain these please:

Transpiration Pull

Root Pressure

cohesion-tension hypothesis

Thanks

Would be very nice :-)

Reply 637

parallal

Original post by Kandy_Kain_94

Can someone explain these please:

Transpiration Pull

Root Pressure

cohesion-tension hypothesis

Thanks

*Water is evaporated from the leaves, this creates a tension (or pull).
*Water entering the xylem (through the root hair cell by osmosis) creates an upward push called root pressure.
*Cohesive forces between the water molecules cause them to 'stick' together and form a column. And the water is pulled up as a column through the xylem.

There's also adhesive forces between the walls of the xylem and the water molecules which pulls the walls of the xylem in as the column of water is moving up, which is why the stem/trunk of a plant/tree reduces in diameter during the day.

Reply 638

parallal

Original post by James A

yeah, well ideally i would like a paper that hasnt got a lot of how science works questions, i prefer just knowledge based questions, im aiming for an A to push my grade to an overall A