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

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Has anyone got a official/unofficial mark scheme for the AQA January 2013 unit 2 paper. Even the actual would do :smile:

I haven't but have you got the paper? If so could you upload it onto here?

Reply 261

Aspiring Medic 7

Original post by science-oliver

Also what are the functions of the vacuole?

Lower the water potential in the cell. Water is therefore drawn across by osmosis... also keeps the cell turgid i think.

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Reply 262

science-oliver

I don't understand this negative pressure in the xylem vessels during transpiration, can someone explain it to me in full detail?

Reply 263

science-oliver

Original post by Aspiring Medic 7

Lower the water potential in the cell. Water is therefore drawn across by osmosis... also keeps the cell turgid i think.

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Thank you

Reply 264

Scienceisgood

Original post by science-oliver

I don't understand this negative pressure in the xylem vessels during transpiration, can someone explain it to me in full detail?

That's in relation to atmospheric pressure (pressure in xylem is lower than the atmosphere).

Reply 265

Simran Mars Foster

I WAS TOLD THAT SOME OF THE CONTENT IN THE NELSON THRONES BOOK IS WRONG!?

In the chapter about hemoglobin, there is a chunk of information that is incorrect?

Reply 266

Scienceisgood

Original post by Simran Mars Foster

I WAS TOLD THAT SOME OF THE CONTENT IN THE NELSON THRONES BOOK IS WRONG!?

In the chapter about hemoglobin, there is a chunk of information that is incorrect?

What don't you understand about haemoglobin?

Reply 267

Simran Mars Foster

^ No i mean i was told that some of the content about hemoglobin is wrong!?

Reply 268

science-oliver

Original post by Scienceisgood

That's in relation to atmospheric pressure (pressure in xylem is lower than the atmosphere).

Ahhh right, so how does that occur?

Reply 269

Scienceisgood

Original post by science-oliver

Ahhh right, so how does that occur?

Doubt it will ask how it occurs, however, there is a chance it will give you a graph and it may ask you to explain why the pressure is negative.

Reply 270

science-oliver

Original post by Scienceisgood

Doubt it will ask how it occurs, however, there is a chance it will give you a graph and it may ask you to explain why the pressure is negative.

Why is the pressure lower in the xylem than the atmosphere though? Or is that the same question I've just asked? :colondollar:

Reply 271

Scienceisgood

Original post by science-oliver

Why is the pressure lower in the xylem than the atmosphere though? Or is that the same question I've just asked? :colondollar:

You just repeated yourself.
Simply say that the pressure in the xylem is less negative than the atmospheric pressure.

Reply 272

Swords N Thorns

Original post by Simran Mars Foster

^ No i mean i was told that some of the content about hemoglobin is wrong!?

Oh gosh, which parts? :s-smilie:

Reply 273

chelseafan

Hey guys i've got my Starch amylase tomorrow. Any tips on the actual experient and how to set out the table?

Reply 274

biology911

Original post by Simran Mars Foster

^ No i mean i was told that some of the content about hemoglobin is wrong!?

I’d be interested to hear what’s meant to be wrong in the book. Apart from the obvious howler on page 151 and the slightly confusing reference to four polypeptide chains alongside an emboldened bullet point for primary structure, I can’t see anything.