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AQA BIOL1 Biology Unit 1 Exam - 16th May 2011

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Well the graph shows the ratio of initial and final length against conc.
When the ratio is 1.0 this means that the water potential outside the cell is exactly the same as the water potential inside the cell. Thus any point after 0.3moldm^-3 will mean the water potential inside the cell is larger than the outside and so the cell must be turgid. And the answer to 2 is 0.3 as I have explained above.

That is exactly what I thought but the answer is "anywhere to the left of 0.3M" ???? :s-smilie:

I thought it would be to the right?

Reply 521

301lw

Original post by swiftylol

Wtf is endorsement? That book has a few mistakes including where it says Internal intercostal muscles are used for inhaling :colonhash:

I use steve potter books, chief examiner and that :cool:

omfg there's more than one textbook? :l
wish i knew that before :l

Reply 522

BeejTheone

Original post by soundlikehouse

No you boil the test solution with dilute hydrochloric icid and then neautralise it with sodium hydrogencarbonate. And then just carry our the benedicts test as normal. :smile:

Thanks, but do you boil when you carry out the benedicts test or just heat? CGP says heat, Teacher said boil :s-smilie:

Reply 523

Spongebobu

Original post by DoaaK

omfg there's more than one textbook? :l
wish i knew that before :l

There are smaller collins biology books made per unit. they are nothing special, the nelson ones are pro.

Reply 524

Spongebobu

Original post by animal*nature

That is exactly what I thought but the answer is "anywhere to the left of 0.3M" ???? :s-smilie:

I thought it would be to the right?

Hmm maybe there is an error or I am missing something..

Reply 525

Sparkly-Star

Original post by BeejTheone

Thanks, but do you boil when you carry out the benedicts test or just heat? CGP says heat, Teacher said boil :s-smilie:

Gently boiling water? That's what NT says lol.

Reply 526

Spongebobu

Original post by Sparkly-Star

Gently boiling water? That's what NT says lol.

boiling water bath is fine for answer

Reply 527

animal*nature

Discuss the ethical issues regarding the formation and testing a new drug for example ORS

Reply 528

BeejTheone

Original post by Sparkly-Star

Gently boiling water? That's what NT says lol.

Well they both seem to have boil in the answer lol

Reply 529

BeejTheone

Original post by animal*nature

They are trialled on children and the children don't get a choice as parents decide, but has to be trialled on children as the disease mainly affects children. Also blind trialled in clinics, patients have the right to know and may cause harm... etc..

Reply 530

Sparkly-Star

Original post by BeejTheone

Well they both seem to have boil in the answer lol

Lol you can stick heat in as well... Heat the sample gently in boiling water. :p:

Reply 531

swiftylol

Original post by reaperguy

There are smaller collins biology books made per unit. they are nothing special, the nelson ones are pro.

I'm not talking about those ones.

And, the NT books are fine but they can miss things out sometimes. Using them shouldn't be a problem tbh.

(edited 12 years ago)

Reply 532

BeejTheone

Original post by Sparkly-Star

Lol you can stick heat in as well... Heat the sample gently in boiling water. :p:

Well we have an answer then xD

Reply 533

Spongebobu

ors increase the uptake of na+ ions/glucose/sugars into the epithelial cells
this then creates a more negatvie water potential in the epithelial cells and thus water moves in the epithelial cells via osmosis from the lumen thus reducing the effects of diarrhoea

That seems right.

Yes thats correct. External is used for inhalation, internal for exhalation. ;D

Reply 536

BeejTheone

The transmission and effect of cholera are actually really easy to understand.
1) Cholera enters small intestine lumen by drinking contaminated water
2) Produces toxin which open chloride ion protein channels in epithelial cells
3) Chloride ions build up in lumen, Water potential decreases
4) Water moves into the lumen, By osmosis. = Diarrhoea

And ors just basically changes water potential back and has reverse effect