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

    0
    ReputationRep:
    (Original post by aiden1234)
    aaaah ace thanks i was getting confused with the different BACs i didnt realise they had to be seperate ! thankyou!
    So then how do they put the entire genome back into correct order? Each section has been sequenced but there is no overlapping between different sections?
    • Thread Starter
    Offline

    0
    ReputationRep:
    did everyone manage to download the question pack i posted earlier?
    if you didnt download it, or maybe you just forget, here it is:

    http://www.thestudentroom.co.uk/show...66390&page=106
    Offline

    0
    ReputationRep:
    do we ave 2 no about self pollination
    Offline

    1
    ReputationRep:
    I haven't done any biology for the last 2 days. I've got a C3 exam tomorrow so should get back top biology after that.

    I just feel like I know so little. Like when doing some past questions my answers are so little little and generally get like 2 marks out of 5/6 mark questions as I know know the stuff vaguely.
    Offline

    0
    ReputationRep:
    (Original post by _lynx_)
    I feel like I've missed out on so much knowledge thought :p:

    Ah I did so well at AS biology, but I feel my revision strategy for A2 may have jeopardized my chances of getting what should have been a comfortable A! It all went downhill after getting my ISA marks for bio - I knew I had little chance of getting an A* so I just focused on Chemistry instead. :rolleyes: At least I've learnt my lesson.

    You're going to walk all over this exam!
    Actually what seems to happend to you, has happend to me as well :P
    Although i did exactly what i did at AS and then...my A2 bio just went sort of down from the high A in AS. Although ive been focussing on biology, argh i just dont know what to do/how to improve from what happend in F214 lol.
    Here i am doing questions now on the ecology unit :P
    Offline

    0
    ReputationRep:
    I've been so focused on biology, that i have barely starte my chemistry, thankfully my teacher is going through it with me today, but i really am not looking forward to next week.
    Offline

    13
    ReputationRep:
    (Original post by MasterJomi)
    I haven't done any biology for the last 2 days. I've got a C3 exam tomorrow so should get back top biology after that.

    I just feel like I know so little. Like when doing some past questions my answers are so little little and generally get like 2 marks out of 5/6 mark questions as I know know the stuff vaguely.
    Don't worry, you are not alone

    (Original post by Falcon91)
    Actually what seems to happend to you, has happend to me as well :P
    Although i did exactly what i did at AS and then...my A2 bio just went sort of down from the high A in AS. Although ive been focussing on biology, argh i just dont know what to do/how to improve from what happend in F214 lol.
    Here i am doing questions now on the ecology unit :P
    Well let us hope for the best! I've never really crammed for an exam before, so this may be a first for me.
    Offline

    0
    ReputationRep:
    (Original post by _lynx_)
    Don't worry, you are not alone

    Well let us hope for the best! I've never really crammed for an exam before, so this may be a first for me.
    Aye Good luck!

    Also, i see your going on a gap year? out of interest have you got a uni place? if so what course?
    Offline

    13
    ReputationRep:
    (Original post by Falcon91)
    Aye Good luck!

    Also, i see your going on a gap year? out of interest have you got a uni place? if so what course?
    Unfortunately, I received no offers this year; I applied for medicine.

    How about you?
    Offline

    0
    ReputationRep:
    (Original post by _lynx_)
    Unfortunately, I received no offers this year; I applied for medicine.

    How about you?
    I applied for Dentistry, no offers this year either.
    Offline

    0
    ReputationRep:
    How can fragments of DNA be placd into plasmids, with reference to ligase?
    I don't really understand the textbook, so it's hard to re write my notes
    Offline

    0
    ReputationRep:
    (Original post by nbailey8)
    How can fragments of DNA be placd into plasmids, with reference to ligase?
    I don't really understand the textbook, so it's hard to re write my notes
    The easiest way to think of it, is think of DNA ligase as glue/tape.

    What happens, is that the gap which is made by the restriction enzyme, to cut open the plasmid has sticky ends. these are complementary to those on gene cut by the SAME restriction enzyme.

    So in order to put the gene into the plasmid/vector and make sure its bound to the plasmid, is use DNA ligase. Incubate the gene and the plasmid with DNA ligase. DNA ligase catalyses the reaction (condensation) which seals the sugar-phosphate backbone of DNA and so it seals the gene into the plasmid.
    Offline

    0
    ReputationRep:
    (Original post by Falcon91)
    The easiest way to think of it, is think of DNA ligase as glue/tape.

    What happens, is that the gap which is made by the restriction enzyme, to cut open the plasmid has sticky ends. these are complementary to those on gene cut by the SAME restriction enzyme.

    So in order to put the gene into the plasmid/vector and make sure its bound to the plasmid, is use DNA ligase. Incubate the gene and the plasmid with DNA ligase. DNA ligase catalyses the reaction (condensation) which seals the sugar-phosphate backbone of DNA and so it seals the gene into the plasmid.
    Thank you it makes more sense now!
    I want lots of module 1, 3 and 4 and not much of 2!
    Offline

    1
    ReputationRep:
    (Original post by Falcon91)

    Describe, using an example, primary succession.
    My 1000th Post

    And it goes to succession. Urrgh.

    Primary succession is the development of a community of organisms from bare rock. A pioneer species will colonise the land, they are able to put up with a lack of soil, and little availability of nutrients (in fact, pioneer species can be related to as being r-stategists- they have a very fast growth rate, and because of this they quickly are able to populate an area, often overshooting the carrying capacity, and then only dieing off, once the limiting factors are too great)
    The dealth and decay, of the pionerr organisms, such as algae and litchen, allow for enough soil and nurtients to accumulate to allow for other species of plant to grow such as moss and fern which can succeed the litchen and algae. This can include nitrogen fixing plants, such as legumes family, which have the bacterium rhizobium present in their root nodules, and this allows for the unreactive nitrogen in the atmosphere to be fixed (nitrification ), allowing for the plants to take in nitrogen which is vital for the production of nucleic acids, and amino acids, which are in turn used to make proteins. This build up of nutrients allows for larger plants to succeed smaller ones, the community of organisms eventually develops into a climax community, in this case it would be a woodland.

    I honestly don't know what we haven't covered now. Um...Describe PCR.
    Offline

    13
    ReputationRep:
    (Original post by Falcon91)
    I applied for Dentistry, no offers this year either.
    Best of luck with your application next year then!
    Offline

    0
    ReputationRep:
    (Original post by _lynx_)
    Best of luck with your application next year then!
    Likewise, Good luck!

    (Original post by ViolinGirl)
    My 1000th Post
    I honestly don't know what we haven't covered now. Um...Describe PCR.
    Congrats @ 1000th post.

    So PCR - used to amplify the amount of DNA when there is very little of it available, this allows more DNA to produced and thus more analysis and tests on it can be carried out. An example where PCR is useful is in crime scene forensics to identify a criminal etc.

    PCR Happens because: 2 DNA strands are antiparallel (one runs 3 prime to 5 prime, the other runs 5prime to 3 prime). And DNA always grows from its 3 prime end.

    Its different to natural, semi-conservative replication because :
    1) PCR uses heating and cooling to break H bonds between strands, whereas natural rep uses a DNA Helicase enzyme to separate strands
    2) PCR uses primers to allow DNA polymerase to bind as it cannot build a complementary strand or bind to it when DNA is single stranded, whereas natural replication doesnt need this
    3) PCR can only be done on shorter lengths of DNA, whereas natural rep can produce a whole DNA strand.

    Stages of PCR:
    1) Mixture containing DNA polymerase, free DNA nucleotides, primers and a length of DNA or a gene is heated to 95 degrees which causes H bonds between bases to break and thus separates the DNA strands
    2) The mixture is cooled to around 55 degrees where it allows primers to anneal (by H bonding) to complementary base sequences at the 3 prime end
    3) Its then heated up to 72 degrees(ish) to allow a thermophilic DNA polymerase (taq mpolymerase taken from bacteria which lice in hot springs so it wont denature + high rate of reaction) to bind to the DNA strand with a primer and build/extend the complementary chain
    4) This is one cycle of PCR, it has doubled the amount of DNA/target molecules present and can then be repeated many times to produce millions of copies of the DNA.

    Hmm. Using an example, give some advantages of social behaviour in primates.
    Offline

    0
    ReputationRep:
    do u guys think its better to do those past paper packs posted or just revise the topics again ?? since the new syllabus is nothing like the old one. i just printed out the ecoysystem pack posted by ' remerkable' and its a 130 pages long !
    Offline

    0
    ReputationRep:
    (Original post by lewdav)
    So then how do they put the entire genome back into correct order? Each section has been sequenced but there is no overlapping between different sections?
    at the beginning of the process they map the whole genome so they know generally what order it is in. This is done before they shear them down into smaller fragments
    Offline

    0
    ReputationRep:
    does anyone else find that when they're doing practice papers the mark schemes are so nit-picky and you're getting the right answer but not using the words THEY want you to use? its so frustrating!!!
    Offline

    1
    ReputationRep:
    (Original post by Falcon91)
    Likewise, Good luck!

    Hmm. Using an example, give some advantages of social behaviour in primates.

    :eek:

    The most straightforward example is that of gorillas, whereby they live in troops of around 10 individuals. There is a dominant male present, the silver back which leads the troop in the search of food and protects the troop from danger. He is the only male that is allowed to mate with the mature females. Once females (produced by the silverback) have matured, these can either stay with the group, or move to other groups (they will mainly move off, because this prevents interbreeding), wheras the mature males have to form new troops and leave because it can create conflict with the dominant male.

    The arrangement can be seen as a heriarchy. The members that have greater importance within the troop are often given benefits, such as being able to mate with the females, or having a large portion of food.

    The advantages of social behaviour are that it can increase the survival rate of the young, as females only give birth to one or very few individuals, and they have a lot of contact with them, and are in charge of their upbringing. They can communicate to one another by facial expressions, and signals, which helps to identify danger/ members of their troop. THey can share info about where food is. Younger males are able to imprint on dominant silverback to learn vital development skills. Dominant silverback involved in protection of younger males. Umm...

    What is Asepsis?
 
 
 
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.