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As biology unit 1 21/5/2014 panic thread watch

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    do i sense some drama
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    (Original post by Alnassenigzig)
    I put two 'pffft's in that response anyone with half a brain would notice im being sarcastic
    grt nw i dnt hv even a half brain.. tht explains it
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    Whatever guys ,if you want to post here it better be constructive
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    anyone help me with mass flow ?
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    (Original post by crazzysashgirl)
    grt nw i dnt hv even a half brain.. tht explains it
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    (Original post by mr osaka)
    anyone help me with mass flow ?
    No clue what that is ,can you be more specific ?I cant find this anywhere in my notes :confused:
    Sure it's on the edexcel specification ?
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    (Original post by Paras Agarwal)
    lol
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    Mass flow is just the idea that substances are transported from one destination to another.
    For example ,the bloodstream carrying useful substances like oxygen and glucose but also waste products like carbon dioxide.

    you should always include mass flow as a part of your answer when the question asks
    "Why do humans and animals need a heart and circulatory system?"
    So in this case you would say Mass flow would important in order to deliver essential substances like Oxygen.
    Without a heart and circulatory system simple diffusion will not be enough to meet the demands of the organism.
    Whereas a heart and circulatory would pump blood continuously in mass flow so oxygen is always readily available.

    (I hope that all made sense >.<)
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    (Original post by Alnassenigzig)
    No clue what that is ,can you be more specific ?I cant find this anywhere in my notes :confused:
    Sure it's on the edexcel specification ?
    i dont know, i saw it in marking scheme. they said idea of "mass flow" , but i never heard about mass flow so whatever
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    (Original post by mr osaka)
    i dont know, i saw it in marking scheme. they said idea of "mass flow" , but i never heard about mass flow so whatever
    hmm what was the question about?
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    (Original post by mr osaka)
    anyone help me with mass flow ?
    mass flow is not in edexcel specification i think,,never came across it,

    but if u wanna knw so badly
    it is unidirectional bulk movement of water wth dissolved substances and suspended particles due to pressure gravity or gradient.

    eg:transport of sucrose dissolved in water in seive tubes

    sry was gonna reply bfr bt frgt,, hope u gt an idea,,
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    Guys is it only me that is forgetting the processes for when there is a lot of water in the membrane, and when there is too little water. The sodium and chloride confuses me
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    does ny1 has a good note on CF? :-/
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    (Original post by Aifas77)
    Mass flow is just the idea that substances are transported from one destination to another.
    For example ,the bloodstream carrying useful substances like oxygen and glucose but also waste products like carbon dioxide.

    you should always include mass flow as a part of your answer when the question asks
    "Why do humans and animals need a heart and circulatory system?"
    So in this case you would say Mass flow would important in order to deliver essential substances like Oxygen.
    Without a heart and circulatory system simple diffusion will not be enough to meet the demands of the organism.
    Whereas a heart and circulatory would pump blood continuously in mass flow so oxygen is always readily available.

    (I hope that all made sense >.<)
    great thanks !!!
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    (Original post by Catb97)
    There is a pattern in the core practical questions - well as in no two the same have come up two years in a row - i reckon either enzymes or beetroot should come up this time, and definitely not vit c

    I think enzymes came up in the Jan international paper so maybe beetroot or Daphnia. I'd agree with definitely not vit c
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    (Original post by particlestudent)
    Guys is it only me that is forgetting the processes for when there is a lot of water in the membrane, and when there is too little water. The sodium and chloride confuses me
    It confuses me too
    Just remember that faulty cftr protein somehow doesn't let Cl- ions to move out and inhibits the sodium pumps from pumping out Na+ ions which creates an electrochemical gradient. This causes the watee to move IN the cell making the mucus abnormally sticky! ( I REALLY hope I have this right by now)

    Make sure you say the word 'abnormally' coz I saw in so many examiner's reports that mucus is sticky anways so you need to say something like 'abnormal' or 'extra'

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    For the Daphnia experiment could you just say-

    Make a range of different caffeine solutions
    Transfer one daphnia onto a cavity slide
    Place the slide under a microscope, focusing it on the heart
    Add the first caffeine solution to the daphnia
    Measure the amount of heartbeats in 15 seconds
    Then times the value by 4 to get beats per minute
    Repeat with the other solutions
    Compare results
    Keep temperature the same??? and what else

    And also I don't actually know why caffeine affects heart rate??? Why is this...
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    (Original post by particlestudent)
    For the Daphnia experiment could you just say-

    Make a range of different caffeine solutions
    Transfer one daphnia onto a cavity slide
    Place the slide under a microscope, focusing it on the heart
    Add the first caffeine solution to the daphnia
    Measure the amount of heartbeats in 15 seconds
    Then times the value by 4 to get beats per minute
    Repeat with the other solutions
    Compare results
    Keep temperature the same??? and what else

    And also I don't actually know why caffeine affects heart rate??? Why is this...
    Volume of caffeine solution should be kept constant as well as the size of daphnia.
    You also need a control with no (0%) caffeine solution so you can compare the heart rate.

    Posted from TSR Mobile
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    (Original post by HQazi)
    Volume of caffeine solution should be kept constant as well as the size of daphnia.
    You also need a control with no (0%) caffeine solution so you can compare the heart rate.

    Posted from TSR Mobile
    So for the zero solution, I use a pipette to extract a large daphnia from the pond solution, and place it on a cotton ball. Then I don't know the rest....
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    (Original post by particlestudent)
    So for the zero solution, I use a pipette to extract a large daphnia from the pond solution, and place it on a cotton ball. Then I don't know the rest....
    No you use distilled water just like you use caffeine solutions and count the heart beats
    It doesn't matter if its large or small, just need to be of similar size.

    Download the app for a level biology (with yellow icon) it has all the core practicals

    Posted from TSR Mobile
 
 
 
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