This discussion is now closed.

Check out other Related discussions

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

I crashed and burned on my ISA this year! I made the idiotic mistake of keeping the full number for my standard deviation equation and not rounding it up and lost 8 marks! The difference between a B and an E.. I'm angry to say the least!

Posted from TSR Mobile

Reply 541

dooobie_

Does anyone know what topics may be on this paper? I need all the help I can get!

Posted from TSR Mobile

Reply 542

propagation

14

I am a retake student and have done nothing, any advice one what I should do, shall I not bother with the exam and focus on unit 5 and other subjects or is there a way of getting atleast a B in some way?

And anyone able to help and identify to me all the definitions we would need to know for this exam, for a +ve.

Many thanks

Reply 543

Nima123

2

I am retaking the unit 1 biology exam and I would like the examiners report for the jan 2013 paper please.

Reply 544

Nima123

2

Could someone please explain tissue fluid and the oxygen haemoglobin curve to me...

Reply 545

dooobie_

Original post by Nima123

Could someone please explain tissue fluid and the oxygen haemoglobin curve to me...

Me too!

Posted from TSR Mobile

Reply 546

Sapphire123

Original post by Omar Raza

These are really good notes well done :smile:

Question - During DNA replication, DNA replicates. We start with 46 chromosomes. Each chromosome is copied, right ?
BUT does that mean we have 92 chromosomes in 1 cell at a certain stage of the cell cycle !!! ? Just confused :smile:

Can any1 answer this ? :biggrin:

Thx.

Thanks and yes that means at one stage we do have 92!

Reply 547

Melissajwilson

Original post by Nima123

Could someone please explain tissue fluid and the oxygen haemoglobin curve to me...

Curve to the left - higher affinity, picks up (associates) oxygen more readily, dissociates less readily
Curve to the right - low affinity, associates with oxygen less readily, dissociates more readily

Other words...

Left - animal is less active, haemoglobin are fully loaded with oxygen at low partial pressures when there is little oxygen in the environment, dissociated less readily to respiring tissues

Right - animal is more active, haemoglobin are fully loaded with oxygen at higher partial pressures when there is more oxygen present, and is dissociated from haemoglobin to respiring tissues more easily

Animals have different affinities for oxygen, high and low
- due to the shape of the haemoglobin molecule
- Different haemoglobins have different sequences of amino acids, therefore different shapes

Up to 4 O2 molecules can be carried on a haemoglobin in a human

Some fish don't need haemoglobin, oxygen is transported by water

The Bohr effect - the greater the concentration of co2 the more readily oxygen dissociates from oxygen (blood is more acidic, changing the shape of the haemoglobin protein)

Posted from TSR Mobile

Reply 548

myah_94

OP

12

hey..can someone please explain Q 5)d)ii) on the June 2010 paper

Reply 549

Simran Mars Foster

12

Ugh i hope we don't get many heart questions. Hate the damn topic.

By the way do we have to know how monoclonal antibodies are obtained or just the uses?

Reply 550

Nima123

2

Original post by Melissajwilson

Curve to the left - higher affinity, picks up (associates) oxygen more readily, dissociates less readily
Curve to the right - low affinity, associates with oxygen less readily, dissociates more readily

Other words...

Left - animal is less active, haemoglobin are fully loaded with oxygen at low partial pressures when there is little oxygen in the environment, dissociated less readily to respiring tissues

Right - animal is more active, haemoglobin are fully loaded with oxygen at higher partial pressures when there is more oxygen present, and is dissociated from haemoglobin to respiring tissues more easily

Animals have different affinities for oxygen, high and low
- due to the shape of the haemoglobin molecule
- Different haemoglobins have different sequences of amino acids, therefore different shapes

Up to 4 O2 molecules can be carried on a haemoglobin in a human

Some fish don't need haemoglobin, oxygen is transported by water

The Bohr effect - the greater the concentration of co2 the more readily oxygen dissociates from oxygen (blood is more acidic, changing the shape of the haemoglobin protein)

Posted from TSR Mobile

thank you for explaining this to me it helped

Reply 551

starfish232

Wondering if someone could please answer queries about the may 2011 paper

1. Question 1(b) has one of the marks as osmosis being reduced but wouldn't osmosis increase as water potential inside the cell reduced so wouldn't water move into cell as a result?
2. Question 5(b) has the answer that it decreases chance of error but I don't understand how?

http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-MS-JUN11.PDF

Thanks

Reply 552

The Lawful T.J

9

Original post by starfish232

Wondering if someone could please answer queries about the may 2011 paper

1. Question 1(b) has one of the marks as osmosis being reduced but wouldn't osmosis increase as water potential inside the cell reduced so wouldn't water move into cell as a result?
2. Question 5(b) has the answer that it decreases chance of error but I don't understand how?

http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-MS-JUN11.PDF

Thanks

Right. Starch is insoluble. This helps it with being used for storage as it won't alter the water potential of the plant/cells. This means that the water from the pond won't go into the cell because there's no osmotic change.

- Tom

Reply 553

Scienceisgood

21

Original post by starfish232

Wondering if someone could please answer queries about the may 2011 paper

1. Question 1(b) has one of the marks as osmosis being reduced but wouldn't osmosis increase as water potential inside the cell reduced so wouldn't water move into cell as a result?
2. Question 5(b) has the answer that it decreases chance of error but I don't understand how?

http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects/AQA-BIOL2-W-MS-JUN11.PDF

Thanks

5B is about there being smaller units of measurement allowing for a greater degree of accuracy, I suppose it would could be used as an example in the following;

Would you rather measure your hand in cm or millimetres (the measurement is to the nearest whole unit), it would be more accurate to say something like 157mm than 16cm if you think about it, right?

(edited 10 years ago)

Reply 554

JBTRKT

Original post by Sapphire123

Thanks and yes that means at one stage we do have 92!

There is actually still only 46 chromosomes after DNA replication, but 92 chromatids and double the mass of DNA. The chromosomes after DNA replication exist as double armed chromosomes- there is 46 of these. :biggrin:

Reply 555

starfish232

Original post by Scienceisgood

5B is about there being smaller units of measurement allowing for a greater degree of accuracy, I suppose it would could be used as an example in the following;

Would you rather measure your hand in cm or millimetres (the measurement is to the nearest whole unit), it would be more accurate to say something like 157mm than 16cm if you think about it, right?

So it's better to measure something in smaller units than bigger units as if an error is made then it wouldn't be magnified soo much compared to if you measure in a bigger unit.
Is that right?

Reply 556

starfish232

Original post by The Lawful T.J

Right. Starch is insoluble. This helps it with being used for storage as it won't alter the water potential of the plant/cells. This means that the water from the pond won't go into the cell because there's no osmotic change.

- Tom

Thanks

Reply 557

Scienceisgood

21

Original post by starfish232

So it's better to measure something in smaller units than bigger units as if an error is made then it wouldn't be magnified soo much compared to if you measure in a bigger unit.
Is that right?

Yep.

Reply 558

Son234

Not too late to just start my revision

1 week to memorise the entire unit word for word

1 week full of past papers

looking forward to this 2 weeks :smile:

This was posted from The Student Room's iPhone/iPad App

Reply 559

Rumschpringe

11

Hi, for all those sitting BIOL2 this June, here is a topic analysis doccument. It contains a chart of all topics covered in AQA BIOL2 and which past papers they appeared in. This could help us to predict what topics the main questions could be on. Some topics seem to appear in every paper and others not so much. Hope it helps.

BIOL2 Topic Analysis.docx16.9KB

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

Related discussions

Latest

Trending

Trending

Articles for you