OCR Biology F211 Exam - Tues 11'th January 2011

hope higher than for u
a question, why can't the first shell hold more than two electrons?

Let's hope bronchus is right then xD

For that water thing - I'm pretty sure the question was, "How does water move across the cell surface membrane?"
Surely symplast and vacuolar are describing what the water does once it's passed through the plasma membrane, not describing how water actually enters the cell in the first place?
I put that water on its own is small enough to pass through the bilayer via osmosis, but if there are solutes / larger molecules with it, then channel proteins may have to facilitate the diffusion.?

yeah i thought that at first aswell but if you have the OCR text book on page 73 that pretty much looks like their question and the answer theyd answer.

hope u get higher than that lol
a question, why can't the first shell hold more than two electrons?

Cause it has only 1 orbital?

because they are ****ed up lol!

what did u gyz put for da one about the smoke travel through the wood??

I think i put something like that too .. and for the one before about histamine making the muscle contract or something, that was to do with cell receptor molecules / target cells etc right? the questions were a bit strange, hard to know what they wanted from us.



i put symplast etc for that one too.. quite a few people did i think but a lot of people but about cell membrane bilayer channel proteins etc! maybe they'll except both because the question could be either? (or lets hope so...)
oh gosh most of the questions were way too vague! or those "suggest..." questions .... where was all the "meaty" stuff on the heart, lungs, translocation, haemoglobin, lymph, cardiac cycle ... etc that we spent soo long revising!!? i think the "suggest" questions and the ambiguity on this paper made it harder than a lot of the past papers we've done

Same book, page 22/23.

Confusion.


Edit: 26/27, sorry.

How does water move between cells?
When plant cells are touching each other,water molecules can pass frome one cell to another.......etc etc.
What ROUTE can water take between cells?
the apoplast pathway
the symplast pathway
the vacuolar pathway

2nsquared formula
the 1st shell is 2*1(squared) = 2 thats the formula answer
but yeah explanation is it only has 1 subshell which is the 1s orbital which is also only capable of containing 2 electrons but dont think theyd ask for it in that much detail. im worried about those mole questions with 10 tonnes of a substance >.<.

God that was such a weird question. I had no idea what to put. I think something about it being able to travel through the xylem uninterrupted because it was a long tube or something. I think I've got that one wrong.

26/27 refers to osmosis the question asked the routes water molecules take to cross the cell surface membrane
quote page 73:

info on p 26/27 would be more relevant if osmosis was used in the question or if osmosis was explained as a route somewhere on p26/27.

lol... i put sumthing abt pits and since it said steam.. i said through the xylem by capillary action

spot on!

lets clear this up... water enters the plasma membrane by diffusing straight throught the phospholipid bilayer by osmosis and through channel proteins by facillitated diffusion. no answers involved apoplast symplast etc