This discussion is closed.
dooobie_
Badges: 0
Rep:
?
#541
Report 6 years ago
#541
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
0
dooobie_
Badges: 0
Rep:
?
#542
Report 6 years ago
#542
Does anyone know what topics may be on this paper? I need all the help I can get!

Posted from TSR Mobile
0
propagation
Badges: 2
Rep:
?
#543
Report 6 years ago
#543
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
0
Nima123
Badges: 2
Rep:
?
#544
Report 6 years ago
#544
I am retaking the unit 1 biology exam and I would like the examiners report for the jan 2013 paper please.
1
Nima123
Badges: 2
Rep:
?
#545
Report 6 years ago
#545
Could someone please explain tissue fluid and the oxygen haemoglobin curve to me...
0
dooobie_
Badges: 0
Rep:
?
#546
Report 6 years ago
#546
(Original post by Nima123)
Could someone please explain tissue fluid and the oxygen haemoglobin curve to me...
Me too!

Posted from TSR Mobile
0
Sapphire123
Badges: 0
Rep:
?
#547
Report 6 years ago
#547
(Original post by Omar Raza)
These are really good notes well done
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
Can any1 answer this ? Thx.
Thanks and yes that means at one stage we do have 92!
0
Melissajwilson
Badges: 0
Rep:
?
#548
Report 6 years ago
#548
(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
1
myah_94
Badges: 10
Rep:
?
#549
Report Thread starter 6 years ago
#549
hey..can someone please explain Q 5)d)ii) on the June 2010 paper
0
Simran Mars Foster
Badges: 12
Rep:
?
#550
Report 6 years ago
#550
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?
0
Nima123
Badges: 2
Rep:
?
#551
Report 6 years ago
#551
(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
0
starfish232
Badges: 0
Rep:
?
#552
Report 6 years ago
#552
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...W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects...W-MS-JUN11.PDF

Thanks
0
The Lawful T.J
Badges: 9
Rep:
?
#553
Report 6 years ago
#553
(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...W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects...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
0
Scienceisgood
Badges: 21
Rep:
?
#554
Report 6 years ago
#554
(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...W-QP-JUN11.PDF
http://filestore.aqa.org.uk/subjects...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?
0
JBTRKT
Badges: 0
Rep:
?
#555
Report 6 years ago
#555
(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.
0
starfish232
Badges: 0
Rep:
?
#556
Report 6 years ago
#556
(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?
0
starfish232
Badges: 0
Rep:
?
#557
Report 6 years ago
#557
(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
0
Scienceisgood
Badges: 21
Rep:
?
#558
Report 6 years ago
#558
(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.
0
Son234
Badges: 0
Rep:
?
#559
Report 6 years ago
#559
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


This was posted from The Student Room's iPhone/iPad App
0
Rumschpringe
Badges: 9
Rep:
?
#560
Report 6 years ago
#560
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.
Attached files
1
X
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • University of Bristol
    Undergraduate Open Afternoon Undergraduate
    Wed, 23 Oct '19
  • University of Exeter
    Undergraduate Open Day - Penryn Campus Undergraduate
    Wed, 23 Oct '19
  • University of Nottingham
    Mini Open Day Undergraduate
    Wed, 23 Oct '19

Have you made up your mind on your five uni choices?

Yes I know where I'm applying (129)
64.5%
No I haven't decided yet (42)
21%
Yes but I might change my mind (29)
14.5%

Watched Threads

View All