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OCR Biology AS Jan Wed 14th

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My book says 0.5...
KipperSlapper
Yup im taking it too. Revising atm hehe (well should be). Can someone clear something up, is the max resolution for electron microscopes 0.1nm or 0.2nm? I find different answers everywhere, even in the same book o.O

0.2nm because the wavelength is 0.4nm!!!
Reply 22
Avatar for smflesh
smflesh
OP
2
Wow okay.. everyone has different max. resolutions for the electron microscope..
Yeh my notes say 0.1nm (these were made in class) whereas my OCR AS Bio textbook says 0.2nm
smflesh
Wow okay.. everyone has different max. resolutions for the electron microscope..
Yeh my notes say 0.1nm (these were made in class) whereas my OCR AS Bio textbook says 0.2nm



I emailed ocr before christmas, and also the other day, and they reply and say, we'll get back to you shortly, I'll email them again tomorrow, if they've not replied, and if it comes up in the exam, and they don't reply, I say that we can get the marks not counted for it, since it would be so unfair.
Reply 24
Avatar for gradu
gradu
8
I emailed ocr before christmas, and also the other day, and they reply and say, we'll get back to you shortly, I'll email them again tomorrow, if they've not replied, and if it comes up in the exam, and they don't reply, I say that we can get the marks not counted for it, since it would be so unfair.


im seeing you around alot lately :smile:

and ye, thats very clever thinking!
theres so much to remember that its putting me off even revising for it argh :frown:
Glad to see im not the only one who can't find a definate answer on that one. My Heinemann book says 0.1nm on one page and 0.2nm on another! If they ask us, they'll have to do something like allow any value between 0.1 and 0.5 or something.
gradu
im seeing you around alot lately :smile:

and ye, thats very clever thinking!




I know. :wink:


I normally lurk, rather than post, and then read all the threads, but since I have all these exams, I post. :wink:
I'll probably post here closer to the exam guys, unless I have a question :biggrin:
Reply 29
Avatar for smflesh
smflesh
OP
2
Hmm an idea. If asked for the max. resolution of an electron microscope, we could say '< 0.5nm'
I think it would be better to put a definitive answer.. Looking around theres quite a few resources that say 0.1nm although theres a "High-resolution transmission electron microscopy" that can achieve up to 0.08nm but doubt we'd be expected to know that. I really think they'll say anthing between 0.1 and 0.5nm is correct, so im going with 0.1nm.

You watch, it wont even come up in the exam :P
Reply 31
Avatar for Sam4God
Sam4God
10
arggggh guys, the exam's in 4 days!! good luck
Width of the phospholipid membrane in the textbook says 7-10nm. Yet everytime the question has come up in an exam, the mark scheme states 7nm and only 7nm.
I don't think there's any leeway going to be allowed with the resolving power of electron microscopes either. I'm going to stick with the figures in the OCR textbook and hope they're "right".
Reply 33
Avatar for v1oXx-
v1oXx-
12
The mock mark scheme as ****. So precise and missed out so many things. But my teacher marks for OCR Biology and she said that a few OCR teacher and the board get together and decide the markscheme taking into account what textbooks say. So 7-10 nm for the phospholipid bilyar is right!

How big is a prokarayote? 10um?
v1oXx-


How big is a prokarayote? 10um?


We dont need to know that do we?

What method of transport does glucose travel by?
definite_maybe
We dont need to know that do we?

What method of transport does glucose travel by?



It goes through cell membranes by carrier proteins, rather than a channel protein... but if you mean through the blood ect, maybe as diffusion? I don't think we need to know that.
Reply 36
Avatar for steph_v
steph_v
13
I'm absolutely terrified.
I had Chem on Friday, and I'm just so not in the mindset for exams. I came out of a longterm relationship on Tuesday, and haven't been able to think straight. It's ridiculous, this exam is more important than him.
My usual revision technique is to write out a question for every bullet point in the specification and then answer them several times. But there is SO much stuff for Biology.
Reply 37
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steph_v
13
Also, how did everyone find the specimen paper? As in, the only one there is for this topic. I found it really easy, but I bet it's misleading, as always.
steph_v
I'm absolutely terrified.
I had Chem on Friday, and I'm just so not in the mindset for exams. I came out of a longterm relationship on Tuesday, and haven't been able to think straight. It's ridiculous, this exam is more important than him.
My usual revision technique is to write out a question for every bullet point in the specification and then answer them several times. But there is SO much stuff for Biology.



I know....


History's worse though.
skatealexia
It goes through cell membranes by carrier proteins, rather than a channel protein... but if you mean through the blood ect, maybe as diffusion? I don't think we need to know that.


So by active transport rather than facilitated diffusion?

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