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    (Original post by maisie__x)
    Would you mind explaining osmoregulation to me? apart from that I think it's mainly the suggest questions that stump me
    Hopefully I can :-). Everyone, if I'm wrong, please correct me. It'll help us all learn xx.

    Right, OSMOREGULATION is basically the control of water and salt levels in the body, and it is needed to maintain the correct water balance between cells and surrounding fluids - this prevents any problems with OSMOSIS.

    It is to do with the COLLECTING DUCT - which is impermeable to water. However it can become permeable if water needs to be conserved. This allows more water reabsorption which increases the concentration of urine further.

    It also adjusts ADH CONCENTRATION in the blood.

    Steps:

    •Water potential in the blood is monitored by OSMORECEPTORS in the HYPOTHALAMUS of the brain.
    •If the water potential of the blood is LOW, osmoreceptors SHRINK and this stimulates NEUROSECRETORY cells in the hypothalamus. (You should know the neurosecretory cells are just specialised hormones).
    •These produce and release ADH, which flows down the axon to the POSTERIOR PITUITARY GLAND - it is stored there.n
    •Neurosecretory glands are stimulated, so they see action potentials down axons, causing ADH to be released into the blood.
    •ADH enters capillaries and is transported around the body, acting on cells in the COLLECTING DUCT eventually.
    •ADH then binds to receptor there and cause a chain of enzyme catalysed reactions, causing vesicles with AQUAPORINS (water permeable channels) to be inserted into the membranes of cells in the collecting duct, making it permeable to water.
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    I think that there's more but this is what I remember. I did draw some diagrams on it but I am busy doing photosynthesis at the moment so I don't have them in my vicinity. I hope that I helped in some way. If not, I am so sorry XD. Forgive me xx
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    I dont suppose anybody has a link to the June 2014 F214 paper and mark scheme please?
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    i have to revise this in 4 days. I pretty much know all the topics apart from excretion. What's the best way to revise?!
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    I have a feeling there is going to be a question on dialysis, have not seen a question on it in a past paper yet.
    What do we need to know about the different dialsysis methods:
    1. dialysis
    2. haemodialysis
    3. peritoneal dialysis
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    what do we need to know about the divergence and convergence of the synapse(or neurone idk) could someone explain it please?
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    F215 - if we were asked "outline the steps involved in sequencing the genome of an organism" - would you talk about genome mapping, BAC's and then how to sequence a BAC section? What kind of detail would we need to add in to answer this question? Possible 8 or 9 marker, so just wondering. cheers x
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    (Original post by YouAgain)
    I personally suggest revising past papers from 2013 and 2012 because I highly doubt that they'd be repeating the same questions as last year's I did thatfor f212 and f211 exams and it was on point
    okay fab!! Thank you
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    (Original post by lustandturqoise)
    what do we need to know about the divergence and convergence of the synapse(or neurone idk) could someone explain it please?
    Convergence and Divergence is to do with synapses between axons and how many axons can be on one side

    Convergence is when multiple axons meet together to trigger depolarisation in the post synaptic knob. This is good because multiple areas of the body can pick up on a stimulus and cause a response.

    Divergence is when a single presynaptic knobs acetylcholine can reach multiple post synaptic knobs , this is good because whan a stimulus is picked up by the bosy the action potential can be sent to different parts of the body for a response.

    This is my understanding if anyone thinks this isnt right just say
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    (Original post by Retakes)
    Convergence and Divergence is to do with synapses between axons and how many axons can be on one side

    Convergence is when multiple axons meet together to trigger depolarisation in the post synaptic knob. This is good because multiple areas of the body can pick up on a stimulus and cause a response.

    Divergence is when a single presynaptic knobs acetylcholine can reach multiple post synaptic knobs , this is good because whan a stimulus is picked up by the bosy the action potential can be sent to different parts of the body for a response.

    This is my understanding if anyone thinks this isnt right just say
    Is this f214? or f215?
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    (Original post by Retakes)
    Convergence and Divergence is to do with synapses between axons and how many axons can be on one side

    Convergence is when multiple axons meet together to trigger depolarisation in the post synaptic knob. This is good because multiple areas of the body can pick up on a stimulus and cause a response.

    Divergence is when a single presynaptic knobs acetylcholine can reach multiple post synaptic knobs , this is good because whan a stimulus is picked up by the bosy the action potential can be sent to different parts of the body for a response.

    This is my understanding if anyone thinks this isnt right just say
    Convergence and divergence aren't in the f214 spec? Or have I missed something?
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    (Original post by Retakes)
    Convergence and Divergence is to do with synapses between axons and how many axons can be on one side

    Convergence is when multiple axons meet together to trigger depolarisation in the post synaptic knob. This is good because multiple areas of the body can pick up on a stimulus and cause a response.

    Divergence is when a single presynaptic knobs acetylcholine can reach multiple post synaptic knobs , this is good because whan a stimulus is picked up by the bosy the action potential can be sent to different parts of the body for a response.

    This is my understanding if anyone thinks this isnt right just say
    Hey, is this in the textbook by any chance? Never heard of it, so just wondering.
    Thanks
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    (Original post by maisie__x)
    Convergence and divergence aren't in the f214 spec? Or have I missed something?
    My thoughts exactly
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    (Original post by domcandrews)
    Hey, is this in the textbook by any chance? Never heard of it, so just wondering.
    Thanks
    It's not in the spec but if you looks at the OCR Biology book page 20 under 'Role of synapses in the nervous system', you can see that the 1st and 2nd bullet points talks briefly about 'covergence' and 'divergence'.

    I quote:
    - 'Several presynaptic neurones might 'converge' to one post synpatic neurone. This would allow signals from different parts of the nervous system to create the same response. This could be useful where several different stimuli are warning us of danger'


    - 'One presynaptic neurone might 'diverge' to several postsynaptic neurones. This would allow one signal to be transmitted to several parts of the nervous system. This is useful in the reflex arc. One postsynaptic neurone elicits the response while another informs the brain'.
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    (Original post by domcandrews)
    My thoughts exactly
    It is mentioned but this is all it really mentions:
    Several presynaptic neurones may converge together to allow signals from different parts of the nervous system to create the same response.
    One presynaptic neurone may diverge to several post synaptic neurones to allow one signal to be transmitted to several parts of the nervous system- one may elicit a response, and one may inform the brain.

    Hope that helps and it is F214, under the section of spec called..... hang on...
    Outline the roles of synapses in the nervous system.
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    (Original post by YouAgain)
    It's not in the spec but if you looks at the OCR Biology book page 20 under 'Role of synapses in the nervous system', you can see that the 1st and 2nd bullet points talks briefly about 'covergence' and 'divergence'.

    I quote:
    - 'Several presynaptic neurones might 'converge' to one post synpatic neurone. This would allow signals from different parts of the nervous system to create the same response. This could be useful where several different stimuli are warning us of danger'


    - 'One presynaptic neurone might 'diverge' to several postsynaptic neurones. This would allow one signal to be transmitted to several parts of the nervous system. This is useful in the reflex arc. One postsynaptic neurone elicits the response while another informs the brain'.
    (Original post by laurenemilyxx)
    It is mentioned but this is all it really mentions:
    Several presynaptic neurones may converge together to allow signals from different parts of the nervous system to create the same response.
    One presynaptic neurone may diverge to several post synaptic neurones to allow one signal to be transmitted to several parts of the nervous system- one may elicit a response, and one may inform the brain.

    Hope that helps and it is F214, under the section of spec called..... hang on...
    Outline the roles of synapses in the nervous system.
    Thank you both! Yep got it now, many thanks for your help! x
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    Hello guys

    How are your preparations for #f214
    I am worried about it
    Can someone explain what substrate level phosphorylation means ?

    Thanks in advance .... cheeers !

    Posted from TSR Mobile
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    (Original post by LivingLife42)
    I dont suppose anybody has a link to the June 2014 F214 paper and mark scheme please?
    Here you go
    Attached Images
  1. File Type: pdf F214-01 Jun14.pdf (934.0 KB, 70 views)
  2. File Type: pdf F214_MS_Jun14.pdf (166.9 KB, 100 views)
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    (Original post by bburn96)
    Hello guys

    How are your preparations for #f214
    I am worried about it
    Can someone explain what substrate level phosphorylation means ?

    Thanks in advance .... cheeers !

    Posted from TSR Mobile
    I'm worried about it too, I find biology really hard

    I think substrate level phosphorylation is just when a molecule of ADP is phosphorylated (phosphate added) to produce a molecule of ATP. This happens in both glycolysis and the Krebs cycle. Hope that helped
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    Help! For 1 (e) on this: http://www.ocr.org.uk/Images/81699-u...t-specimen.pdf how are you supposed to know what to talk about, i know you need to talk about the operon but, like there's no question if ygm or am i missing something?
 
 
 
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