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AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

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Original post by krane
I know this was a while ago, but does this mean that more transcription factors mean, like, the gene is expressed more times? I thought it was either expressed or not.. but with more transcription factors the code is copied by mRNA..blah blah.. more often, so more chloroplasts would be produced?


I copied that out the CGP guide. I'm not really sure what the answer would be.
Reply 761
Avatar for Gulzar
Gulzar
2
Please can someone help me understand in vivo and in vitro gene cloning. I know that in vivo is when you use restriction endonuclease to cut DNA but why are we doing that...is it because the gene is only a small section of the DNA and we use the restriction enzyme to find it? Then using the cut dna fragment we insert it into a vector, which transports it into an organism.

Secondly, in vitro requires PCR. In PCR have we isolated the gene using restriction endonuclease or reverse transcriptase...or have we just taken the DNA and copied it?
What are the advantages and disadvantages of both these gene cloning techniques.

Notes on these will be greatly appreciated...thanks so much guys
Reply 762
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erniiee
13
Original post by solidsnake1234
Seeing as though there are like 3 exam papers and one specimen paper, how are you guys developing exam technique for this paper? Would it be good to do exam pro, because im worried it will have the current spec paper questions


http://sciencemathsmaster.weebly.com/packs.html
Does anyone know where I can get notes on units 1 and 2?
Reply 764
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currydud
Original post by AtomicMan
Does anyone know where I can get notes on units 1 and 2?

www.getrevising.co.uk
and search for biology unit 1 or 2 and there should be a few resources:smile:
(edited 10 years ago)
Reply 765
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krane
9
Original post by HELPIMSTUCK
I copied that out the CGP guide. I'm not really sure what the answer would be.


Ah okay, I just don't get how transcription factors can cause more of a protein produced in some cells than others, but I'll just go with more tf = more expression
Reply 766
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rommy123
Original post by Rebeelouise
Some more notesssssss


These are great thanks :smile: i was wondering if you've any notes on DNA technology? thanks
Reply 767
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k1rby
10
Original post by krane
Ah okay, I just don't get how transcription factors can cause more of a protein produced in some cells than others, but I'll just go with more tf = more expression


Transcriptional factors bind to the DNA and begin the process of transcription. Transcriptional factor's binding site can be blocked by inhibitors which is when a gene is not expressed. So a cell with more uninhibited transcriptional factors would lead to more of that certain protein being produced. I don't think it's an expressed or not situation as the needs of the cell will vary. Which is why there are hormones like oestrogen that go into cells and bind to receptors on transcriptional factors causing the inhibitor to be released and so can bind to DNA. I welcome correction but I think this is right, hope it helps :smile:
(edited 10 years ago)
Just been making posters for everything! My favourite is my menstrual cycle one which is now on the bathroom door...
Reply 769
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krane
9
Original post by k1rby
Transcriptional factors bind to the DNA and begin the process of transcription. Transcriptional factor's binding site can be blocked by inhibitors which is when a gene is not expressed. So a cell with more uninhibited transcriptional factors would lead to more of that certain protein being produced. I don't think it's an expressed or not situation as the needs of the cell will vary. Which is why there are hormones like oestrogen that go into cells and bind to receptors on transcriptional factors causing the inhibitor to be released and so can bind to DNA. I welcome correction but I think this is right, hope it helps :smile:


Thank you! Yes it helped quite a bit, it's starting to sink in!
Original post by Lizzie232
Just been making posters for everything! My favourite is my menstrual cycle one which is now on the bathroom door...


:lolwut: haha
Original post by rommy123
These are great thanks :smile: i was wondering if you've any notes on DNA technology? thanks


This website has some nice powerpoints on DNA technology: http://vbio.weebly.com/a2-level.html
Reply 772
Avatar for Gulzar
Gulzar
2
Original post by Mocking_bird
I'm going to start looking through New Scientist and just general bits and bobs around the internet to get a few points down that we can share for off spec stuff.... unless theres already a document floating around that people can link me to?


Thats a really good idea actually. We should all research some further reading material and just post links and ideas here :smile:
Original post by frogs r everywhere
:lolwut: haha


I kid you not... I share a bathroom with 9 other girls (Two of which are doing BIOL5) so I thought they'd like to know about it...
WP_20130502_025.jpg499.1KB
Went to Manchester University hospital today:

Gel electrophoresis with my DNA!
WP_20130502_012.jpg489.3KB
Original post by rommy123
These are great thanks :smile: i was wondering if you've any notes on DNA technology? thanks


In progress!!! :smile:


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Original post by farihaaah
Not that if you messed it up you're stupid.


I'm digging myself a hole :frown:


Posted from TSR Mobile

Yes, haha, i really should have read that before posting! :smile:
Original post by Lizzie232
I kid you not... I share a bathroom with 9 other girls (Two of which are doing BIOL5) so I thought they'd like to know about it...


I don't mean to sound rude but I'm having trouble understanding the menstrual cycle (lord knows why since I'm a girl myself) but this looks like a really good poster! Any chance you would be willing to post a view from the front that is readable? :colondollar: I understand if you don't want to advertise your work- just thought it'd be worth asking! :tongue:
Reply 778
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dizzy17
Hi, I have a few questions about DNA fingerprinting: why do we have to transfer the fragments onto a nylon membrane to analyse them, why can't they just be left in the gel? Also, in the book it says that the gel is submerged in an alkali to separate the double strands into single strands- so what happens to the other strand that isn't being analysed ( the other half of the double strand)
Original post by dizzy17
Hi, I have a few questions about DNA fingerprinting: why do we have to transfer the fragments onto a nylon membrane to analyse them, why can't they just be left in the gel? Also, in the book it says that the gel is submerged in an alkali to separate the double strands into single strands- so what happens to the other strand that isn't being analysed ( the other half of the double strand)


They don't do anything to the other strand, probably discard it away. This anyway isn't testing us on the fingerprinting techniques, so it's extremely unlikely they will ask us that. But hey, it's good to be inquisitive though...

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