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    (Original post by nbailey8)
    May someone please summarise the chain termination reaction for me? thanks!
    I'm assuming this is referring to automated nucleotide sequencing, the method of producing genomes...?

    1. Single stranded DNA, free nucleotides, DNA polymerase and primers are mixed together.

    2. Free nucleotides that are fluroscently marked are also placed in the mixture of the above, if these are added to the chain, then they cause the DNA polymerase enzyme to be thrown off.

    3. The primers anneal to sections on the DNA to form some double stranded DNA, this allows for DNA polymerase to bind, and the free nucleotides can be added in thier complementary base pairing rules.

    4. The process of the addition of a fluroescent colured nucleotide being added is random, so varying chain lengths are produced before the polymerase enzyme is thrown off.

    5. These chains can be passed through a laser reader, which detects the colours of the bases for a chain with 1 added nucleotide, to 2, to 3 to 4 etc.....
    And this allows for the sequence of colours and therefore bases to be determined.

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    (Original post by ViolinGirl)
    Haha. Nice squirrel.
    What does the evidence from DRD4 receptors/dopamine show us?
    The DRD4 receptors correlates with information to show that a variation in the gene that codes for the DRD4 receptors can cause abnormal behaviour such as Schizophrenia and ADHD (Attention Deficiet Hyperactivity Disorders). Varying levels of dopamine cause are believed to have caused this. Many atipsychotic drugs work by blocking dopamine receptors.

    This information can be used to identify genes that influence behaviours, i.e. that certain mutations and variations of genes can contribute to certain behaviours. Thus can be useful when utilising genetic screening of individuals and embryos (allowing better/more effective drugs to be identified, using gene therapy for treatments as well as faster/earlier diagnosis of disorders and allows planned treatments too).

    Had to check the book for the part of this just for some detail but the rest i had in memory.

    Describe, using an example, primary succession.
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    finally got the whole callus tissue culture stuck in my head
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    (Original post by ViolinGirl)
    Haha.
    just to add to the tissue culture thing..
    i have been doing biotech and gene tech questions and the main point that always comes up in tissue culture is

    STERILE growth medium
    STERILE soil

    etc. you get my point lol
    just dont want to lose marks over one word
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    (Original post by Archen)
    just to add to the tissue culture thing..
    i have been doing biotech and gene tech questions and the main point that always comes up in tissue culture is

    STERILE growth medium
    STERILE soil

    etc. you get my point lol
    just dont want to lose marks over one word
    Yeah apparently mentioning Asepsis gets you a mark lol. Also some markschemes have been a bit fussy about the use of hormone. Some of them write plant growth regulator.

    doing those questions that were posted on TSR for biotech are SO annoyingly picky lol. And some of them i didnt think we have to know about.
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    (Original post by ViolinGirl)
    I'm assuming this is referring to automated nucleotide sequencing, the method of producing genomes...?

    1. Single stranded DNA, free nucleotides, DNA polymerase and primers are mixed together.

    2. Free nucleotides that are fluroscently marked are also placed in the mixture of the above, if these are added to the chain, then they cause the DNA polymerase enzyme to be thrown off.

    3. The primers anneal to sections on the DNA to form some double stranded DNA, this allows for DNA polymerase to bind, and the free nucleotides can be added in thier complementary base pairing rules.

    4. The process of the addition of a fluroescent colured nucleotide being added is random, so varying chain lengths are produced before the polymerase enzyme is thrown off.

    5. These chains can be passed through a laser reader, which detects the colours of the bases for a chain with 1 added nucleotide, to 2, to 3 to 4 etc.....
    And this allows for the sequence of colours and therefore bases to be determined.


    Thank you - makes a lot more sence now haha
    I was getting slightly confused as we don't need to know about dideoxy nucleotides and when I asked my boyfriend to explain the chain termination he kept talking about that! (He's at uni doing biochem!)
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    Quick question... I was just doing this set of questions and a couple of problems came up:

    It says that in transcription "Both DNA polynucleotide chains act as templates." - how is this the case? Does it just mean because one strand is the template and the other is coding strand which is what the mRNA turns out to be a copy of?

    And also, it says "Part of the DNA base sequence coding for a protein is shown here: A T G G C C T A A G T G - State the corresponding base sequence of mRNA" Does the answer to this not depend on whether the base sequence shown is the coding or template strand? The answer seems to think it's the template strand but how are we meant to know that??

    Thanks
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    Can someone go through plant hormones? Like what each one does, what it's used for etc.
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    Right there's a question i'm stuck on, I'll explain and see if any of you guys (and galz) can help.

    Lambs are in an enclosure. A man (apparently a scientist) went into this enclosure with an umbrella (wtf?), and repeatedly opened and closed this umbrella to scare the lambs, (and obviously these lambs were bricking it in the corner). Eventually though they got used to the annoying man and his umbrella, and completely ignored it.

    I know this is Habituation learning, but I have to suggest two advantages to the lambs of their change in behaviour. Any help? Thanks.
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    (Original post by Alex-92)
    Right there's a question i'm stuck on, I'll explain and see if any of you guys (and galz) can help.

    Lambs are in an enclosure. A man (apparently a scientist) went into this enclosure with an umbrella (wtf?), and repeatedly opened and closed this umbrella to scare the lambs, (and obviously these lambs were bricking it in the corner). Eventually though they got used to the annoying man and his umbrella, and completely ignored it.

    I know this is Habituation learning, but I have to suggest two advantages to the lambs of their change in behaviour. Any help? Thanks.
    Answers are in the back of the book. Energy is not wasted on response and less stress.
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    Has anybody got any past papers they can give me? + rep
    im really desperate..
    thankyou x
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    (Original post by Alex-92)
    Right there's a question i'm stuck on, I'll explain and see if any of you guys (and galz) can help.

    Lambs are in an enclosure. A man (apparently a scientist) went into this enclosure with an umbrella (wtf?), and repeatedly opened and closed this umbrella to scare the lambs, (and obviously these lambs were bricking it in the corner). Eventually though they got used to the annoying man and his umbrella, and completely ignored it.

    I know this is Habituation learning, but I have to suggest two advantages to the lambs of their change in behaviour. Any help? Thanks.
    Er, no psychological changes associated with stress ( fight or flight response link), and no idea for the second :P.
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    (Original post by v1oXx-)
    Can someone go through plant hormones? Like what each one does, what it's used for etc.
    Auxins
    • Promote cell elongation
    • Inhibit growth of side-shoots
    • Inhibit leaf abcission


    Some commercial uses of auxins:
    • Preventing leaf and fruit abscission (Low conc)
    • High concentrations promote fruit drop
    • Treating unpollinated flowers promotes growth of seedless fruit
    • Herbicide to kill weeds
    • Promote growth of cuttings


    Also involved in apical dominance

    Gibberellins (Produced in young leaves and seeds)
    • Promote seed germination
    • Promote growth of stems


    Some commercial uses of Gibberellins:
    • Delay senescence in citrus fruits
    • Sugar production – spraying gibberellins stimulates growth between nodes = more sugar stored in cells of internodes
    • Plant breeding – gibberellins accelerates the breeding process by initiating seed production in young trees (usually takes a long time for conifers)


    Cytokinins
    • Promote cell division


    Some commercial uses of cytokinins:
    • Delays leaf senescence for vegetables such as lettuce. Stays greener for longer
    • Used in tissue culture to help mass-produce plants. Bud and shoot growth promoted so many cuttings can be made


    Abscisic acid
    • Inhibits seed germination and growth
    • Causes stomatal closure during low water levels


    Some commercial uses of abscisic acid:


    Ethene
    • Promotes fruit ripening
    • Stimulates leaf abscission


    Some commercial uses of ethene:
    • Ripen apples, tomatoes and citrus fruits
    • Promote fruit drop in cotton, cherry and walnut
    • Promote lateral growth in some plants
    • Promote female sex expression in cucumbers, which reduces the chance of self-pollination and increasing the yield


    Hope that helps
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    Just one more day then I shall roll on f215 :woo:
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    (Original post by ibysaiyan)
    Just one more day then I shall roll on f215 :woo:
    How much do you know? I know frighteningly little :eek3:
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    (Original post by _lynx_)
    How much do you know? I know frighteningly little :eek3:
    Well.. I have been preparing for this mod. from the day I sat 214 back jan. So yea the only stuff I need to re-read through is: Behavior and exam questions based on genetics WHICH thanks to 12 other exams I haven't managed to go through yet otherwise theory wise I hope I remember .
    See you around . Hang around here for the upcoming 120 hours and you shall ACE it :top:
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    (Original post by Ecstacy.)
    Has anybody got any past papers they can give me? + rep
    im really desperate..
    thankyou x
    check back a couple of pages somebody posted a few documents with loads of past paper questions related to certain topics merged together
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    (Original post by skatealexia)
    Er, no psychological changes associated with stress ( fight or flight response link), and no idea for the second :P.
    Yeah thanks, the stress idea is correct :eek3: , the second point being linked to an energy concept, involving a response to a stimulus that poses no actual threat to the animal, so energy is being wasted. It's just a strange question, not how I treat my lambs but hey.
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    (Original post by chuck111)
    Ok guys,

    Heres the first installment of the revision cards all you guys have been msging me about :P, I started with the hardest topic for me which was the Cloning+Biotechnology. I did them all in one day so i might have missed something out, Please tell me if I have

    Enjoy

    Hey thanks for these really needed them..couldn't get my head round all the processes we have to learn in this module especially all the genetic engineering stuff
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    (Original post by ibysaiyan)
    Well.. I have been preparing for this mod. from the day I sat 214 back jan. So yea the only stuff I need to re-read through is: Behavior and exam questions based on genetics WHICH thanks to 12 other exams I haven't managed to go through yet otherwise theory wise I hope I remember .
    See you around . Hang around here for the upcoming 120 hours and you shall ACE it :top:
    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!
 
 
 
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