OCR Biology F211 Exam - Tues 11'th January 2011

For the cytoskeleton i put vesicles transport substances around cell in and out, something like that. is that right? (i put something else as well it was a 2 marker)

5 marks for the transpiration question! what was there to say?
I mean i mentioned as molecules are lost at the top by evaporation to to high potential of water to low potential, this moves the water column up, mentioning cohesion adhesion that crap.. what else?

everyone keeps talking about a water potential calc question? like 1600 or something?! why can't i remember this?
ahhhhh
it was such a weird exam

I just took the average of the water potential for 57% of the cells and the water potential for 42% and got around -1600kPa

water molecules can pass through via simple diffusion theyre small enough the only time theyd use any form of protein such as aquaporins NOT channel proteins is during pinocytosis.
They asked for the routes which water takes across the cell surface membrane pretty simple to describe two basic pathways across the cell surface membrane abit more complex to mention aquaporins (not in the specification), the size of the water molecules,the charge of the water molecules being irelevant, and pinocytosis which from past papers is generally one mark in itself.
like i said in a previous post i hate grey areas and we'll see when the markscheme comes out. JUST because a pathway can go through a number of cell membranes does not mean it ONLY goes through many cell membranes.

i literally had 2 seconds for that question..saw the 57% value and wrote that down for the answer for 50% value..do you think ill gett he mark? maybeee there would be a range up to 57% ? i dont know lol

hey lol i think you read my comment it was exopinocytosis my friend wrote it and i was confused aswell.. apparently it is in the revision guide i checked it and yh it was in a small little box and ocr always try to pick out the things we dont know fully such as diference between plant and animal cell cell division so yh it does make it seem right..also omsosis could be water leaving the cell OR moving into cell..they specifically said moving out of cell so its exopinocytosis (meaning water moving out of cell)

Its asks for the routes across the cell surface membrane not the routes water takes. Its Osmosis (1) through Protein channels (1). As Water is a polar molecule.

You'd be correct if it asked how water travelled to the Xylem

Please... water never moves through Channel Proteins. It is polar but it is not an ion! I talked about osmosis and defined osmosis. There is another way for water to move. That is through aqua porines but I never wrote that down in the exam. It just didn't come up in my head for some reason :\

Please... water never moves through Channel Proteins. It is polar but it is not an ion! I talked about osmosis and defined osmosis. There is another way for water to move. That is through aqua porines but I never wrote that down in the exam. It just didn't come up in my head for some reason :\

YES this is what I thought, part a) Osmosis and b) was describing Osmosis.

When it said cell surface membrane it surely can't mean through the bilayer which is HYDROPHOBIC or through channel proteins since it's not a charged ion.

omg reading through all of what you guys have written in the exam... i have miserably failed
can someone tell me what that 5mark question answer was? i thought i did good writing about cohesion and adhesion? but was that not correct ?

I wrote that !

yes, pm with your email address

Thought I'd bring this thread up again, seeing as we get the results tomorrow. eeek. (though I dont actually make that sound in real life)

The grade boundaries are really low! :O

Yep, sounds good so far. Approx 11hours 30minutes left for me.