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    (Original post by Talon19921992)
    We won't know the correct moderated UMS conversion until results day but at AS my 37/40 was just on the A borderline. Hoping it won't be that drastic this year as I got 35/40
    huh, that's weird. last year someone at my school got 33/40 and that was an A, and i got 29/40 and it was a C.

    ..guess that just goes to show moderation's effect..
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    (Original post by tara592)
    auxins stimulate cell elongation and inhibit side shoot formation. Auxins are produced at the tips of the shoots, called the apical bud. So when you cut the tip off, you'll get loads of side shoots growing as there's no auxin to inhibit their growth. Also, if theres a really tall plant, its likely there will be side shoots forming near the bottom as there's less auxin at the bottom to inhibit side shoot growth.
    oh and auxins are transported around the plant via active transport, diffusion and mass flow through the phloem sap/xylem vessels.

    can anyone pleasee clear up what we need to know about the brain?
    I have 3 textbooks contradicting eachother...one is just about the cerebrum, cerebellum, medulla and hypothalamus. the other talks about sensory, association and motor areas, and broca and wernickes area. the other talks about meninges, amyglada and the limbic system. (no idea what this is about!)
    please say we dont need to know about that!

    On the syllabus it just says we need to learn about the cerebrum, hypotalamus, medulla oblongata and the cerebellum
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    ahh good!
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    (Original post by chuck111)
    The role of auxins in apical dominance is that they inhibit the growth of lateral buds and increase the growth of the apex, therefore the apex dominates the lateral buds as they are not produced due to the presence of auxins....hmmm

    lol i think most of that is wrong im not very good with the plant/animal responses
    (Original post by tara592)
    auxins stimulate cell elongation and inhibit side shoot formation. Auxins are produced at the tips of the shoots, called the apical bud. So when you cut the tip off, you'll get loads of side shoots growing as there's no auxin to inhibit their growth. Also, if theres a really tall plant, its likely there will be side shoots forming near the bottom as there's less auxin at the bottom to inhibit side shoot growth.
    oh and auxins are transported around the plant via active transport, diffusion and mass flow through the phloem sap/xylem vessels.

    Thank you both. Chuck you were correct. :yy:
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    Where are the eco questions?
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    (Original post by tara592)
    (e)
    describe the role of the brain and nervous system in the co-ordination of muscular movement;
    (f)
    describe how co-ordinated movement requires the action of skeletal muscles about joints, with reference to the movement of the elbow joint


    just got that off the syllabus, any ideas?
    (e)- The cerebellum is involved in the control of movement and the maintainance of posture
    The cerebellum has neurones which carry impulses to the motor areas so that motor output can be adjusted in relation to the requirements

    (f)
    Impulses arrive at a neuromuscular junction
    Vescicles containing acetlycholine fuse with the pre synaptic membrane and release achetyle choline into the gap
    The neurotransmitter binds to the sarcolemma causing depolarisation
    Depolarisation travels down the T-system which leads to Ca2+ ions being released from the sarcoplasmic reticulum
    This Ca2+ binds to proteins in the muscle which lead to contraction (bind to the troponin complex in the actin filament)
    Achetlycholineesterase rapidly breacks down the acytlycholine so that contraction does not keep happnening continuously

    think thats about it
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    Are the synoptic links only going to be to f212 and
    f211? Just looking at the specification and the 'links to other modules' part =D I'm a little obsessed with the synoptic elemant to this exam
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    what are the effects of increased temperature on immobilised enzymes
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    (Original post by chuck111)
    (e)- The cerebellum is involved in the control of movement and the maintainance of posture
    The cerebellum has neurones which carry impulses to the motor areas so that motor output can be adjusted in relation to the requirements

    (f)
    Impulses arrive at a neuromuscular junction
    Vescicles containing acetlycholine fuse with the pre synaptic membrane and release achetyle choline into the gap
    The neurotransmitter binds to the sarcolemma causing depolarisation
    Depolarisation travels down the T-system which leads to Ca2+ ions being released from the sarcoplasmic reticulum
    This Ca2+ binds to proteins in the muscle which lead to contraction (bind to the troponin complex in the actin filament)
    Achetlycholineesterase rapidly breacks down the acytlycholine so that contraction does not keep happnening continuously

    think thats about it
    ooh okay thanks!
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    (Original post by amitpatel44)
    what are the effects of increased temperature on immobilised enzymes
    Immobilised enzymes are more thermally stable, especially in entrapment, because the solid supports provide extra stability to the active site due to bonding.
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    (Original post by amitpatel44)
    what are the effects of increased temperature on immobilised enzymes
    There shouldn't be any effects. They are more stable and still work efficiently at increased temps.
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    hopefully peoples ISA will help their marks .

    did everyone in their school do well. Everyone did worse in my school compared to last year. I think grade boundaries will be lower
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    could someone briefly outine the ways of immobilising enzymes, like really briefly.
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    (Original post by clever)
    could someone briefly outine the ways of immobilising enzymes, like really briefly.
    Adsorption- Enzymes mixed with clays/ porous carbon. Hydrophobic and ionic links. Weak bonds = lots of leakage. High reaction rate as active site not covered.

    Covalent bonding- Cross linking agent used to bond enzymes covalently to clay. Can only immobilise few enzymes. Very little leakage as bonds strong. Active site may be obstructed/ covalent bonds may effect tertiary stru of enzyme.

    Entrapment- in gel beads or cellulose fibres. Active sites free, but takes a little extra time for substrate to move through membrane.

    Membrane separation- Partially permeable membrane used to separate substrate and enzymes.
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    (Original post by mikey_g)
    GOLDEN RICE

    • Vitamin A - forms visual pigment (eyesight), involved in glycoprotein synthesis, maintenance of epithelial cells, and bone growth.
    • Beta-carotene is precursor to vitamin A (retinol), and is eaten when meat isn't available. It's called pro-vitamin A
    • Most enzymes for metabolic pathway for beta-carotene production already present in endosperm. Only 2 genes need to be inserted to activate the metabolic pathway.
    • the genes are psy (Daffodil) and crt1 (soil bacterium)
    • These genes are inserted into a Ti plasmid, forming a recombinant plasmid.
    • The plasmid is taken up by agrobacterium tumefaciens, (transformed bacteria)
    • A. tumefaciens infects rice plant genome with the 2 genes; inserted near specific promoter sequence associated with endosperm development.
    • Gene is transcribed and translated in the endosperm - which produces a protein that synthesises beta-carotene, giving the endosperm a yellow/orange colour, hence golden rice. It is bio fortified (higher conc. of particular nutrient than normal)
    • A marker gene may also be used, so the rice cells only grow on a selective medium.




    name 2 proteins found in the I band - actin and....???:confused:

    Thanks so much!!
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    I bet the person who wrote this paper was probably high as i bet they are going to make it hard
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    could anyone define the different types of learned behaviours plss???
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    (Original post by Nixani)
    could anyone define the different types of learned behaviours plss???


    Habituation - where an animal learns to have a reduced response to an unimportant stimulus that poses no potential threat or benefit.

    Imprinting - a modification of behavuiour that occure during a relatively short window of time early in an organisms life and may last well into adulthood.

    Classical cond - where an animal learns to relate a pair of events and responds to the first in anticipation of the second.

    Operant cond - Where an animal learns to carry out a particular pattern of behaviour that will increase the chances of a benefit or reduce the chances of a threat.

    Latent - "hidden" learning where an animals learning only becomes apparent when placed under certain circumstances.

    Insight - Where an animal intergrates memories arising from two or more pieces of behaviour, in order to produce a new response that achieves a reward.
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    (Original post by chuck111)
    Are you definatley sure this is the only synoptic topics they can ask us?
    Nope. I think they could be some GCSE links into it.
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    36/40 in the ISA. To answer someones questions.
 
 
 
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