Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    Offline

    1
    ReputationRep:
    (Original post by slacker07906)
    LOL I dont know anything. Going to revise till late tonight. Can you claim special circumstances if a family member (dad) has been in hospital?
    Same here I'm gonna go buy some red bull now
    You might be able to, depends on how ill they are I think
    Offline

    0
    ReputationRep:
    (Original post by thepwince)
    Bacterial plasmid has two genetic markers; the resistance for antibiotic ampycillin and the antibiotic tetracycline.
    The gene for insuline, if taken up, is within the coding section for tetracycline, and so bacteria that have uptaken the recombinant DNA will not be able to transcribe the gene fully, and so no longer resistant to tetracycline.

    Replica plating works on this principle;
    -The bacteria are left to grow.
    -Some of this bacteria are grown upon ampycillin agar, and tetracycline agar. (transfered with what i imagine is like a big stamp, so that the arrangement of the bacteria is kept constant - hard to describe)
    -Those with the normal plasmid are resistant to both, and grow on both plates
    -Those with recombinant plasmid grow on ampycillin and not tetracycline.
    -Those with neither do not grow at all.

    So by a process of elimination, those collonies on ampycillin but not tetracycline = recombinant, the ones you want and are identified by comparing the two distributions.

    I hope this helps - its hard to describe the transfer, i think its enough to say 'by keeping track of the transfered collonies' - pretty much what the textbook says.

    Take a look at this diagram - it helps to understand the transfer part

    http://en.wikipedia.org/wiki/File:Replica-dia-w.svg

    Offline

    0
    ReputationRep:
    (Original post by sportycricketer)
    If thats the case, it shouldn't be too bad
    thats what I was thinking....
    Offline

    0
    ReputationRep:
    (Original post by fortunecookie)
    Could we potentially get something like this? It is a legacy paper, but I'm struggling to work out if it is relevant or not?

    10)
    In this question, one mark is available for the quality of spelling, punctuation and grammar.
    The figure below shows the left side of the cerebrum of a human.

    "Picture of a Brain"

    A person is reading a book. Outline the events that take place in the nervous system from the time an image of a word is formed on the retina to the time that word is recognised by the brain.
    You may refer to the figure in your answer.
    (Allow one lined page)

    I answered that question with the whole impulse to cerebrum, etc. but after I looked at the mark scheme, I realised that the whole answer for that question was about the structure of the cerebrum in detail, etc. which we don't need to know. So that particular question won't come up But if something similar to that comes up, I'm guessing you should answer it with a description of formation of action potential in the sensory neurone, followed by impulse to brain, then to effector, etc.
    Offline

    8
    ReputationRep:
    (Original post by -Jaz-)
    1. A conjugation tube forms between two bacteria
    2. A nick forms in the plasmid of one bacteria
    3. The plasmid unravels and is passed into the next bacteria
    4. The exposed bases are replicated
    5. The new plasmid and the old coil back into circles again
    6. Nicks are sealed by DNA ligase
    7. The conjugation tube breaks off

    Helpful?
    ooh yes thanks so much!
    Offline

    0
    ReputationRep:
    WHAT IS A GANGLION?
    and whats it on about when it says that the parasympathetic: the neurones of a pathway are linked at a ganglion within target tissues so pre ganglionic neurones vary in length

    and

    post ganglionic (omg what is this word lol) neurones secret acetylcholine as neurotransmitter at synapse between neurone and effector

    could someone just outline differences between sympathetic and para in a way that i can understanf the whole ganglion business
    Offline

    0
    ReputationRep:
    (Original post by -Jaz-)
    1. A conjugation tube forms between two bacteria
    2. A nick forms in the plasmid of one bacteria
    3. The plasmid unravels and is passed into the next bacteria
    4. The exposed bases are replicated
    5. The new plasmid and the old coil back into circles again
    6. Nicks are sealed by DNA ligase
    7. The conjugation tube breaks off

    Helpful?
    Do you need to know this? Swear the spec says outline the advantages of it?

    Scared, havent looked at it :|
    Offline

    0
    ReputationRep:
    (Original post by sillysal)
    ooh yes thanks so much!
    Good luck for Monday
    Offline

    0
    ReputationRep:
    (Original post by emma237)
    Do you need to know this? Swear the spec says outline the advantages of it?

    Scared, havent looked at it :|
    Definitely need to know it - it's in our book :/ The Heinemann one
    Offline

    0
    ReputationRep:
    What grade is 64/100?
    Offline

    0
    ReputationRep:
    (Original post by -Jaz-)
    Definitely need to know it - it's in our book :/ The Heinemann one
    But on the OCR specification it doesnt say you need to know the process, only 'outline the advantages of conjugation' :/
    Offline

    1
    ReputationRep:
    (Original post by entertheOJI)
    What grade is 64/100?
    It depends on what the grade boundaries are but it'll be around a low A/high B
    Offline

    0
    ReputationRep:
    What do we think the odds are for a Hardy-Weinberg principle question? How would they format the question? My guess would be that they would give us the p and q values and it would be a similar set up to the chi-squared questions.
    Offline

    0
    ReputationRep:
    (Original post by hellosarah)
    Thank you soo much!!
    So we don't need to know about Abscisic acid at all then?
    We need to know that abscisic acid inhibits seed germination and stem growth. Also when a plant is stressed due to low water availability, absisic acid causes stomatal closure
    Offline

    0
    ReputationRep:
    (Original post by -Jaz-)
    Definitely need to know it - it's in our book :/ The Heinemann one
    If a question says how the bacterial population becomes resistant to antibiotics do we talk about selection pressure, natural selection, selective advantage etc or conjugation or both?
    Offline

    0
    ReputationRep:
    (Original post by sickofexamz)
    Hey could someone clarify this for me. In the heinemann book on 2.2 spread 4 do we need to know the information in the table or is it just the paragraph under the table?
    Thanx
    A few examples from the table would be good to know but mainly the paragraph below- a few examples of why microorganisms are used in biotechnology
    Offline

    0
    ReputationRep:
    (Original post by 786girl)
    WHAT IS A GANGLION?
    and whats it on about when it says that the parasympathetic: the neurones of a pathway are linked at a ganglion within target tissues so pre ganglionic neurones vary in length

    and

    post ganglionic (omg what is this word lol) neurones secret acetylcholine as neurotransmitter at synapse between neurone and effector

    could someone just outline differences between sympathetic and para in a way that i can understanf the whole ganglion business
    1. A ganglion is a mass of nerve cell bodies - basically, its like a the separation between the central nervous system and the peripheral nervous system.

    2. Post ganglionic neurone is the part of the neurone after the ganglion. If a post ganglioic neurone secretes acetylcholine as the neurotransmitter, it is part of the parasympathetic nervous system.

    3. Sympathetic nervous system - in a nutshell, FIGHT OR FLIGHT.
    - it increases the heart rate, ventilation rate, etc.
    - causes radial bundles of smooth muscle in retina to contract, causing pupil dilation
    - has a very long POST-ganglionic neurone, because the ganglion is in the spinal cord.

    4. Parasympathetic nervous system - REST AND DIGEST - I think of it as a parachute that brings me down :P
    - decreases heart rate, ventilation rate, etc.
    - causes circular bundles of smooth muscle in retina to contract, causing pupil constriction
    - has a long PRE-ganglionic neurone because the ganglion is near the effector muscle.

    Any help?
    Offline

    0
    ReputationRep:
    (Original post by sportycricketer)
    If a question says how the bacterial population becomes resistant to antibiotics do we talk about selection pressure, natural selection, selective advantage etc or conjugation or both?
    First talk about mutation / variation existing in population
    Then selection pressure, selective advantage, survival of mutants, etc.
    Then mention conjugation tubes - passing on resistance
    Offline

    13
    ReputationRep:
    hey guys....

    don't bother focusing on the second module (the biotech one) as 54% of all the marks in the last paper (jan 2011) came from that module, hence they are very very very very very very unlikely to focus/ask too much on it

    EDIT: I know this as I went through it and counted
    Offline

    0
    ReputationRep:
    (Original post by infernalcradle)
    hey guys....

    don't bother focusing on the second module (the biotech one) as 54% of all the marks in the last paper (jan 2011) came from that module, hence they are very very very very very very unlikely to focus/ask too much on it

    EDIT: I know this as I went through it and counted
    Ah well that sucks! I quite like that one :P Oh God, if they hit us with ecology I will scream and run out of the exam hall!
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: June 13, 2012
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?

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.