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    (Original post by nomrota95)
    what is/are the difference(s) between habituation and adaptation? what brings them both about?
    no one answered :'( was my question that stupid
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    (Original post by nomrota95)
    no one answered :'( was my question that stupid
    Habituation is becoming habituated to a repeated stimulus, i.e you stop responding to it (the core practical with the snails). Adaptation is related to habituation, as you have adapted to the stimulus, but the definition for adaptation on its own is an alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relation to its environment.
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    (Original post by ebainbridge)


    Habituation is becoming habituated to a repeated stimulus, i.e you stop responding to it (the core practical with the snails). Adaptation is related to habituation, as you have adapted to the stimulus, but the definition for adaptation on its own is an alteration or adjustment in structure or habits, often hereditary, by which a species or individual improves its condition in relation to its environment.
    thankyou!
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    (Original post by nomrota95)
    no one answered :'( was my question that stupid
    Habituation is when you stop responding to a neutral stimulus. The response is lost for a long period of time (sometimes even permanently) unless you are specifically sensitised to it because the calcium ion channels in your pre-synaptic membrane have become less responsive.

    Adaptation is (or at least I think it is) linked with accommodation of the synapses, when your receptor cells adapt to a stimulus they stop sensing it because the neurotransmitters at the synapses need time to be re-synthesised, but if you remove the stimulus for a while then bring it back the neurotransmitters are replaced so you can sense it again.

    I look at the difference as habituation being long-term loss of response and adaptation as short-term loss of response.
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    okay so there are no jan 2010 papers for this unit..isnt it?
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    (Original post by RnTf)
    Can someone explain what is transcription factor??
    Transcription factors control the transcription of the genes. They travel to the nucleus from cytoplasm and can either activate transcription or stop transcription.

    We have to know there are two types of transcription factors - Activators and Repressors.

    Activators stimulate transcription of genes. they help RNA polymerase bind to the target gene thus activates transcription.
    Repressor inhibits transcription of genes. they bind to target genes thus preventing RNA polymerase from binding to it. thus, transcription stops.


    - RNA polymerase catalyses the transcription of genes.
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    (Original post by iwantopas19)
    okay so there are no jan 2010 papers for this unit..isnt it?
    Nope, just 7 papers from june 10-now + a specimen.

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    Do you guys think we need to know the structure of the eye?

    Is chemiosmosis basically just oxidative phosphorylation/ETC or is it more?
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    (Original post by RnTf)
    Can someone explain what is transcription factor??
    It's basically a protein that binds to DNA to switch certain genes on or off for transcription - if it switches genes on then it's called an activator, if it switches genes off then it's a repressor. I think at our level that's all we really need to know :P

    EDIT : factors that switch on genes are activators, my bad.
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    (Original post by TheNoobyPotato)
    Do you guys think we need to know the structure of the eye?

    Is chemiosmosis basically just oxidative phosphorylation/ETC or is it more?
    I don't remember the eye structure being part of the spec...and it's never been asked before o_O

    There's a bit more to chemiosmosis. Basically the NADH and FADH release hydrogen atoms, they split into H+ (protons) and electrons. The electrons enter the electron transport chain and as they are passed from one carrier to another energy is released which is used to actively transport the protons into the intermembrane space.

    So there's more H+ in that space than there is in the matrix. H+ will tend to want to leave this space due to concentration and electrochemical gradient - they can only leave through the ATP synthase molecule. As they go through ATP synthase, this enzyme synthesises new ATP molecules. H+ then combines with electron and oxygen to form water.

    So the ETC is one part but the proton gradient is pretty important too.
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    (Original post by joan2468)
    Habituation is when you stop responding to a neutral stimulus. The response is lost for a long period of time (sometimes even permanently) unless you are specifically sensitised to it because the calcium ion channels in your pre-synaptic membrane have become less responsive.

    Adaptation is (or at least I think it is) linked with accommodation of the synapses, when your receptor cells adapt to a stimulus they stop sensing it because the neurotransmitters at the synapses need time to be re-synthesised, but if you remove the stimulus for a while then bring it back the neurotransmitters are replaced so you can sense it again.

    I look at the difference as habituation being long-term loss of response and adaptation as short-term loss of response.
    all clear! thanks alot! )
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    Can someone explain why opsin causes the sodium channel to close? And what does the retinal do?

    One more thing... why is it when no neurotransmitter is released at the synapse the bipolar cell stimulates action potential?
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    (Original post by TheNoobyPotato)
    Do you guys think we need to know the structure of the eye?

    Is chemiosmosis basically just oxidative phosphorylation/ETC or is it more?

    NO, u dont need to know the structure, its not in the spec.. but if u have free time no harm in learning
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    Guys im still worried aboout the scientific article. What do you think the main points are for it
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    (Original post by TheNoobyPotato)
    Nope, just 7 papers from june 10-now + a specimen.

    Posted from TSR Mobile


    where can i get the specimen ? :/
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    (Original post by bubblegummer)
    Can someone explain why opsin causes the sodium channel to close? And what does the retinal do?

    One more thing... why is it when no neurotransmitter is released at the synapse the bipolar cell stimulates action potential?
    Rhodopsin bleaching stimulates a cascade reaction that closes the channels, the more rhodopsin that is bleached the more sodium channels close and the greater the hyperpolarisation of the rod cells.

    I'd just think of opsin and retinal as two components of the rhodopsin, really.

    And if you're referring to the CGP Revision Guide explanation, it's referring to inhibitory neurotransmitters. When a large enough generator potential is created in the rod cell inhibitory neurotransmitters are not released so this allows an action potential to be generated in the bipolar cell.
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    could someone define both negative feedback and homeostasis for me PLEASE ?
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    Anyone can upload the specimen papers both ques and ans ?thx

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    in glycolysis, "a small amount of ATP is also made available directly from the energy transfer when the 3C sugar is converted to pyruvate. the phosphorylation of the sugar at the beginning of the glycolyisis is reversed when the final intermediate compound is converted to pyruvate. the phosphate group released is used to convert ADP to ATP" - do we need to remember this part as answers to questions relating gycolysis, aerobic respiration, etc? :/ or just the part with hydrogen removed from the 3C, which taken up by NAD to reduce it and pass on to the elctron carrier system, where the energy made available is used to phosphorylate ADP into ATP is enough?
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    the spec doesnt mention cytochromes or cytochrome oxidase in the electron transport chain, do we have to know about them?
 
 
 
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