Hey there! Sign in to join this conversationNew here? Join for free
    Offline

    0
    ReputationRep:
    (Original post by subsist)
    Hey guys just wanted to check that i got genome sequencing sorted. The chromosome is sheared into sections of DNA that are all 100 000 base pairs. Now if we focus on one of those sections, they get inserted into a BAC and then inserted into E coli. The E coli is cultured and left to reproduce so that there are many copies of the BAC and the DNA section in it. The BAC's are extracted from the cells and the DNA sections are extracted from the DNA. Now there are many copies of that 100 000 base pair section and this is then mixed with a range of different restriction enzymes to create fragments of DNA of differing lengths. These are then sepearted by the process of electropheresis in orded of size and then each of these fragments are taken one by one and undergo automated sequecing so that we know the base sequence of each of the fragments. A computer than detects overlapping regions from the cuts made by the restriction enzymes in these fragments and arranages the whole 100 000 base pair sequence in the right order. CORR BLIMEY thats a typful.
    Here's a summary of genome sequencing I made, the book has a really confusing layout so I summarised it on one page hope this helps. Yours is pretty much right though, but for the automated sequencing part you can talk about the chain termination method in detail.
    Attached Images
  1. File Type: pdf Genome sequencing.pdf (192.4 KB, 330 views)
    Offline

    0
    ReputationRep:
    (Original post by jamedz)
    Here's a summary of genome sequencing I made, the book has a really confusing layout so I summarised it on one page hope this helps. Yours is pretty much right though, but for the automated sequencing part you can talk about the chain termination method in detail.
    Cheers your a legend. I'm giving you a thumbs up!!!!! ( new to this).
    Offline

    0
    ReputationRep:
    (Original post by sillysal)
    someone care to explain the graduation of response concept?
    This is all about the strength of contraction of muscles. For example you don't need the level of contraction for walking as you do for running.

    -The brain controls the strength of the contaction as many motor neurones can stimulate a single muscle. There are loads of motor neurones connected to the muscles by neuromuscular junctions and the more that are stimulated, the bigger the contraction.
    Offline

    0
    ReputationRep:
    (Original post by subsist)
    Cheers your a legend. I'm giving you a thumbs up!!!!! ( new to this).
    No worries lol. I'm feeling a big essay coming up on genome sequencing! That's why I made that. Hoping it's on the sliding filament theory though tbh.
    Offline

    2
    ReputationRep:
    Ok i get confused between genome sequencing (all the BAC stuff) and automated DNA sequencing.. Can someone please explain when i would write about which?!
    I can just see myself writing a full essay on the wrong thing 'cos they both sequencing.
    Offline

    0
    ReputationRep:
    (Original post by Wor Carroll)
    Who else needs an A overall in Biology?
    i need an A in every exam to get an overall B in the course...but thats neva gonna happen is it? No way, i 've only revised ecosystems yet, not looked at anything else and i've not even touched da revsion for chem exam which is 2 days afta F215 exam!
    Offline

    2
    ReputationRep:
    (Original post by Rosi M)
    Ok i get confused between genome sequencing (all the BAC stuff) and automated DNA sequencing.. Can someone please explain when i would write about which?!
    I can just see myself writing a full essay on the wrong thing 'cos they both sequencing.

    The BAC stuff is just additional knowledge, it's how the human genome project was worked out if anything

    Basically, BAC is to produce multiple copies of DNA fragments, giving a clonal libary - and giving overlapping fragments, because you cut the DNA fragments with restriction enzymes.

    Then, it's just the automated sequencing method, otherwise known as the Chain-termination method:

    1) DNA fragments are mixed with free DNA nucleotides, DNA primers, DNA polymerase and (flourescently labelled nucleotides, known as terminator bases)
    2) The primer anneals(binds) to the 3' end of the DNA strand, so DNA polymerase can attach free DNA nucleotides to it.
    3) Then, a terminator base will be attached, and this will throw off DNA polymerase, so the fragment of DNA will stop at a specific place

    So now, you use electrophoresis where the fragments of DNA are seperated by there length > the shorter fragments will go through the gel quicker, and also will then reach the end where it will be exposed to UV light, and whatever colour it gives off will be fed into a computer system to show an electrophoresis graph.

    Therefore, your then able to work out the colour sequence, which shows one of four colours (for the terminator bases which are flourescently labelled) > and then work out the sequence of nucleotide bases, as the shortest DNA fragment will always have one nucleotide, then another will have two. etcetc.

    Hope that helps
    Offline

    0
    ReputationRep:
    Errmmm I am not clear about the UMS

    What is the total UMS for the whole subject ..as in AS and A2 + the practical..and what percent of the UMS do you need to get A - B - C etc etc...
    Offline

    0
    ReputationRep:
    (Original post by 182blink)
    Errmmm I am not clear about the UMS

    What is the total UMS for the whole subject ..as in AS and A2 + the practical..and what percent of the UMS do you need to get A - B - C etc etc...
    UMS wise you need:

    480/600 - A
    420/600 - B
    etc etc
    Offline

    1
    ReputationRep:
    (Original post by Waqar Y)
    The BAC stuff is just additional knowledge, it's how the human genome project was worked out if anything

    Basically, BAC is to produce multiple copies of DNA fragments, giving a clonal libary - and giving overlapping fragments, because you cut the DNA fragments with restriction enzymes.

    Then, it's just the automated sequencing method, otherwise known as the Chain-termination method:

    1) DNA fragments are mixed with free DNA nucleotides, DNA primers, DNA polymerase and (flourescently labelled nucleotides, known as terminator bases)
    2) The primer anneals(binds) to the 3' end of the DNA strand, so DNA polymerase can attach free DNA nucleotides to it.
    3) Then, a terminator base will be attached, and this will throw off DNA polymerase, so the fragment of DNA will stop at a specific place

    So now, you use electrophoresis where the fragments of DNA are seperated by there length > the shorter fragments will go through the gel quicker, and also will then reach the end where it will be exposed to UV light, and whatever colour it gives off will be fed into a computer system to show an electrophoresis graph.

    Therefore, your then able to work out the colour sequence, which shows one of four colours (for the terminator bases which are flourescently labelled) > and then work out the sequence of nucleotide bases, as the shortest DNA fragment will always have one nucleotide, then another will have two. etcetc.

    Hope that helps
    where you mention electrophoresis, should we write out the procedure for that too?
    Offline

    1
    ReputationRep:
    (Original post by Killmepls)
    wtf is that lol
    lol someone's just explained it to me so I'll explain it to you. Basically, the motor neurones stimulate a muscle, contract a cluster of muscle cells. The more muscle cells stimulated, the greater the force of contraction and this is known as the graduation of response
    Offline

    0
    ReputationRep:
    in a few older papers with the old specification i've looked at, there seems to be a variety of different answers for a question about succession. The question usually says
    explain what is meant by succession
    (3 marks)

    what, in everyones opinion, is the best answer to that on the new spec?


    please quote me if anyone replies
    Offline

    1
    ReputationRep:
    (Original post by katie93)
    in a few older papers with the old specification i've looked at, there seems to be a variety of different answers for a question about succession. The question usually says
    explain what is meant by succession
    (3 marks)

    what, in everyones opinion, is the best answer to that on the new spec?


    please quote me if anyone replies
    I'd guess something along the lines of

    Succession describes the stages 'seres' of development of an area, starting with the pioneer species colonising the inhospital habitat, and finishing with the climax community where there is high biodiversity, and many interactions between them.

    I guess the key points for that question would be mentioning that its development, and that each stage is a sere. And then where it starts and finishes. If it was worth more marks I'd probably make the distinction between primary and secondary succession.

    EDIT: DIRECTIONAL CHANGE. So important. Man I need to revise this... So when I said you need to mention its develoopment, I meant that you need to say its the directional change.
    Offline

    1
    ReputationRep:
    (Original post by katie93)
    in a few older papers with the old specification i've looked at, there seems to be a variety of different answers for a question about succession. The question usually says
    explain what is meant by succession
    (3 marks)

    what, in everyones opinion, is the best answer to that on the new spec?


    please quote me if anyone replies
    directional change in the number of organisms and species, where pioneer species first inhabit the area and stabilise the area by producing nitrates and soil and stabilising with their roots. More species can then succeed these, with increasing number of organisms until climax community reached.

    something like that??
    Offline

    0
    ReputationRep:
    Posting here to procrastinate from revising Gene Technology which is so boring :nothing: I've only got that and Animal Responses and Behaviour left to revise, but I've probably forgotten all the stuff I revised earlier.
    Offline

    2
    ReputationRep:
    (Original post by katie93)
    in a few older papers with the old specification i've looked at, there seems to be a variety of different answers for a question about succession. The question usually says
    explain what is meant by succession
    (3 marks)

    what, in everyones opinion, is the best answer to that on the new spec?


    please quote me if anyone replies
    Since it's three marks I would say:

    Succession is the directional change in a community of organisms overtime, occurs in stages and begins with a pioneer species which lives in an unhabitated area, e.g rock - lichens and mosses grow, they are decomposed to produce organic matter for other plants to grow on.
    Offline

    2
    ReputationRep:
    (Original post by sillysal)
    where you mention electrophoresis, should we write out the procedure for that too?
    I wouldn't, unless the question specifically asks for it.
    Offline

    1
    ReputationRep:
    Anyone staying up tonight to revise?
    Offline

    0
    ReputationRep:
    (Original post by heartskippedabeat)
    Anyone staying up tonight to revise?
    I stay up every night to revise Though to be fair it probably makes up for my obscene waking-up time...

    Why can I read a sentence and then 10 seconds later not be able to recall it? Ugh
    Offline

    1
    ReputationRep:
    (Original post by bzzz)
    I stay up every night to revise Though to be fair it probably makes up for my obscene waking-up time...

    Why can I read a sentence and then 10 seconds later not be able to recall it? Ugh
    Haha, I seem to be getting up stupidly early recently, whatever time I go to bed :confused: Think it's my brain's way of telling me to get up and revise

    Argh I know, it's so frustrating. Nothing sticks What grade are you aiming for?
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.