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    (Original post by baymax96)
    Ahh I understand everything up until 'Water follows from the PCT into the PCT wall as Na are removed from the PCT' maybe bc I don't understand the structure:/ but thank you
    I remember the structure like this:

    BLOOD CAPILLARIES

    _____

    TISSUE FLUID

    ______

    CELL (lining the PCT)

    ______

    INSIDE PCT, TUBULE FLUID.

    So they're all next to each other like that. The cell lining the PCT has a lower water potential than the tubule fluid inside the PCT, so water diffuses down its water potential gradient from high water potential to low water potential by osmosis into the cell.
    Did that help?
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    (Original post by QwertyBio)
    Hey guys.

    Based on previous exams for F214, the following has not come up as much, and was not present in last year's paper:

    - Control of heart rate
    - Synaptic transmission
    - Aerobic Respiration
    - Respirometer experiment
    - Photosynthesis
    - ADH/osmoregulation.

    Please understand that this is not an exhaustive list. I strongly recommend everybody go through the specification which is available on the OCR website. If you are not comfortable with every point, then go through it. Good luck to you all, my friends!
    I can't find a respiration experiment in the textbook, ( sorry if I've missed it). I can remember one from AS? Is that the one you mean?
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    (Original post by QwertyBio)
    Hey guys.

    Based on previous exams for F214, the following has not come up as much, and was not present in last year's paper:

    - Control of heart rate
    - Synaptic transmission
    - Aerobic Respiration
    - Respirometer experiment
    - Photosynthesis
    - ADH/osmoregulation.

    Please understand that this is not an exhaustive list. I strongly recommend everybody go through the specification which is available on the OCR website. If you are not comfortable with every point, then go through it. Good luck to you all, my friends!
    Thank you so much!
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    (Original post by maisie__x)
    I can't find a respiration experiment in the textbook, ( sorry if I've missed it). I can remember one from AS? Is that the one you mean?
    It's in the CGP book (pg 149 if you have the AS and A2 book), I only just realised myself it was in there! I wasn't able to find it in the OCR textbook either...

    I would take a pic of the page in the book but my phone's being an ass.

    Basically if you want to investigate the rate of oxygen uptake in respiration, you set up a respirometer.

    The respirometer has two test tubes, one containing something that respires e.g. woodlice, the other test tube being a control, so it contains glass beads. These two test tubes are connected by capillary tubing that contains a dyed liquid. The control is used to prove that only the woodlice respiring will cause the uptake of oxygen.

    KOH is present in the test tube with the woodlice to absorb any CO2.

    Leave the apparatus for a set time e.g. 20 mins, measure how far the liquid in the manometer has moved (the woodlice respiring will cause a decrease in pressure in the respiromete, so the dye will move). Use this to calculate vol of oxygen taken in by woodlice per minute. Keep other conditions e.g. temperature, constant. Repeat experiment, calc mean of vol of oxygen per minute, = more reliable results
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    No worries!
    (Original post by coolerthanbeans)
    Thank you so much!
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    (Original post by coolerthanbeans)
    It's in the CGP book (pg 149 if you have the AS and A2 book), I only just realised myself it was in there! I wasn't able to find it in the OCR textbook either...
    No I don't have the CGP guide :') is it complicated?
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    (Original post by coolerthanbeans)
    It's in the CGP book (pg 149 if you have the AS and A2 book), I only just realised myself it was in there! I wasn't able to find it in the OCR textbook either...
    Could you summarise it on here if you're free to? I don't have the CGP revision guide
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    (Original post by Munrot07)
    Honestly, it is good to know but don't actually spend time revising an AS topic unless it comes up at A2 and you don't understand it. For example, if you are revising the loop of henle you need to know about transport across membranes, if you don't know this then go back and revise it but otherwise don't worry. The synoptic questions will not come straight from an AS textbook. They will be A2 topics which require AS knowledge so you should be able to tell what knowledge is needed from the A2 topics.
    Thank you very much. Your videos helped me get an A at AS biology and I'm hoping I can do the same this year.
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    (Original post by maisie__x)
    No I don't have the CGP guide :' is it complicated?
    (Original post by baffledchick)
    Could you summarise it on here if you're free to? I don't have the CGP revision guide
    Summarised it in an edit of my earlier post
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    Hey Guys

    Which areas from AS biology come up?? I am just trying to cover the synoptic aspect of the course
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    (Original post by coolerthanbeans)
    I remember the structure like this:

    BLOOD CAPILLARIES

    _____

    TISSUE FLUID

    ______

    CELL (lining the PCT)

    ______

    INSIDE PCT, TUBULE FLUID.

    So they're all next to each other like that. The cell lining the PCT has a lower water potential than the tubule fluid inside the PCT, so water diffuses down it's water potential gradient from high water potential to low water potential by osmosis into the cell.
    Did that help?
    Yes it did! Thanks for your patience and help would you also be able to go through the loop of henle?
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    (Original post by coolerthanbeans)
    Summarised it in an edit of my earlier post
    Thank you!!
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    (Original post by LA_95)
    Does anyone think beta oxidation will come up? If so where is the info on what we need to know because I can't find much in the book about it

    Posted from TSR Mobile
    Anyoneeee?

    Posted from TSR Mobile
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    (Original post by QwertyBio)
    Hey guys.

    Based on previous exams for F214, the following has not come up as much, and was not present in last year's paper:

    - Control of heart rate
    - Synaptic transmission
    - Aerobic Respiration
    - Respirometer experiment
    - Photosynthesis
    - ADH/osmoregulation.

    Please understand that this is not an exhaustive list. I strongly recommend everybody go through the specification which is available on the OCR website. If you are not comfortable with every point, then go through it. Good luck to you all, my friends!
    Ah yeah, these are exactly what I've been thinking too thanks! except i forgot about and haven't revised for the respirometer experiment :/
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    (Original post by utsav12)
    Hey Guys

    Which areas from AS biology come up?? I am just trying to cover the synoptic aspect of the course
    Potentially anything but it won't be too detailed and would be 1/2 marks max
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    [QUOTE=bbadonde2;56712851]Potentially anything but it won't be too detailed and would be 1/2 marks max[/QUOTE

    Thank you
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    (Original post by baymax96)
    Yes it did! Thanks for your patience and help would you also be able to go through the loop of henle?
    Sure thang!

    Baaaaaaasically
    You've got your ascending limb of the loop of Henle, that's slightly thicker in width than the descending limb.
    This ascending limb has walls that are impermeable to water (hence why it's so hefty), and ions (Na+ and Cl-) are actively transported out of the ascending limb, into the medulla. This lowers the medulla's water potential. From the medulla, these ions diffuse into the descending limb, which has walls that are permeable to water. Seeing as the medulla's water potential is pretty low since a bunch of ions were actively transported into it earlier, water diffuses out of the descending limb down it's water potential gradient into the medulla by osmosis, where it can enter the blood capillaries (so we can keep hydrated and all that jazz).

    Ions then diffuse out of the bottom of the ascending limb, so the medulla's water potential decreases again. So once again, water diffuses by osmosis again into the medulla down it's water potential gradient, but this time from the collecting duct. Then the water enters blood capillaries again.

    How was that?
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    (Original post by LA_95)
    Anyoneeee?

    Posted from TSR Mobile
    I don't think it's in the syllabus, but from what I remember I think it's just how lipids get respired if they're being used as a respiratory substrate.
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    (Original post by coolerthanbeans)
    Sure thang!

    Baaaaaaasically
    You've got your ascending limb of the loop of Henle, that's slightly thicker in width than the descending limb.
    This ascending limb has walls that are impermeable to water (hence why it's so hefty), and ions (Na+ and Cl-) are actively transported out of the ascending limb, into the medulla. This lowers the medulla's water potential. From the medulla, these ions diffuse into the descending limb, which has walls that are permeable to water. Seeing as the medulla's water potential is pretty low since a bunch of ions were actively transported into it earlier, water diffuses out of the descending limb down it's water potential gradient into the medulla by osmosis, where it can enter the blood capillaries (so we can keep hydrated and all that jazz).

    Ions then diffuse out of the bottom of the ascending limb, so the medulla's water potential decreases again. So once again, water diffuses by osmosis again into the medulla down it's water potential gradient, but this time from the collecting duct. Then the water enters blood capillaries again.

    How was that?
    Ahhh tysm again!!! So helpful

    Edit: how is there water in the ascending limb if the water is lost by osmosis in the descending limb?
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    ****!

    I did a f215 paper and scanning electron microscopes came up

    How the **** do they expect us to still have f211 stuck in our heads?

    -__-

    Posted from TSR Mobile
 
 
 
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