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AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011 Watch

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    (Original post by M.A.)
    Just looked at the spec and it says " The technique of genetic fingerprinting .... and its use in determining the genetic variability within a population."

    what does this mean?! and how would you determine the variability?
    i think it just means that if the banding patterns produced by the gel electropheresis (during genetic fingerprinting) are similar in a population then there is little genetic variability(the individuals will have similar core sequences), whereas if the pattern produced by genetic fingerprinting is extermely different for individuals in a population then the genetic variability will be high. ?? i think :confused:
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    Auxins

    I hate them and the CGP revision guide isn't helping.

    On phototrophism it says of the roots: 'IAA moves to [one] side - growth is inhibited so root bends away from the light.'

    How is growth inhibited..why? And if growth is inhibited, why is it able to bend? Surely bending is growth? :confused:
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    (Original post by emmaaa65)
    i finished going over chapter 13 yesterday which im still struggling with but ohwell!
    im going to start going over chapter 14 today and hopefully get all the genetics stuff out of the way by the middle of this week... i hate chapters14-16 theyre so long!!!
    after thats done im going to go over past exam papers and all that stuff!
    this exam is getting to close! :eek:
    I'm pretty much in the same situation, I've covered up to chapter 13 but still feel like there are reasonable gaps in my knowledge from what I've learnt, still got quite a lot of work to do! At least we have just over 2 weeks left so we're not out of time yet!

    (Original post by Destroyviruses)
    Yey welldone! You said so much. I'm probably say something dumb like, the phrovide phospates to change ADP back ATP, 'nuf said! And lose A LOAD of marks!
    Thanks! We should ask more questions, I really find it helpful for revision!

    (Original post by Tericon)
    Auxins

    I hate them and the CGP revision guide isn't helping.

    On phototrophism it says of the roots: 'IAA moves to [one] side - growth is inhibited so root bends away from the light.'

    How is growth inhibited..why? And if growth is inhibited, why is it able to bend? Surely bending is growth? :confused:
    Right, what happens is initially IAA is produced from cells at the shoot tip and is transported down the shoot to all sides. When light is directed from one side it causes the movement of IAA from the light side to the shaded side. The concentration of IAA increases on the shaded side and as IAA causes plant cells to elongate it causes the shaded side to undergo more growth/elogation than the side the light is being directed from.

    If you imagine, this causes the shoot to bend towards the light as the light side is growing more slowly than the shaded side.

    Just for clarification, if we talk about roots, in root cells higher concentrations of IAA decrease growth so for the same reason this causes plant root cells to bend away from light and IAA collects on the light side, which elogates faster than the shaded side to the plant bends towards the shaded side and grows into the soil.

    I'm not sure if that is clearer? If it's still confusing let me know and I'll try to draw/find a diagram or something for you.
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    (Original post by Tericon)
    Auxins

    I hate them and the CGP revision guide isn't helping.

    On phototrophism it says of the roots: 'IAA moves to [one] side - growth is inhibited so root bends away from the light.'

    How is growth inhibited..why? And if growth is inhibited, why is it able to bend? Surely bending is growth? :confused:
    I have no idea on how growth is inhibited. If anything, I thought the plant grows more. This is my explanation for IAA:

    1) IAA causes plants to elongate.
    2) Cells in the tip of the shoot produce IAA. This is transported down the shoot.
    3) Light causes the movement of IAA to move from the light side to the shaded side of the shoot.
    4) Greater concentration of IAA builds up on the shaded side rather than light side.
    5) This causes shoot to elongate more.
    6) The shaded side of the shoot grows faster causing the shoot to bend towards the light.

    Edit: Is the point in bold the way growth is inhibited? Because the light causes it to move to the shaded side? :confused:
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    (Original post by INeedToRevise)
    I have no idea on how growth is inhibited. If anything, I thought the plant grows more. This is my explanation for IAA:

    1) IAA causes plants to elongate.
    2) Cells in the tip of the shoot produce IAA. This is transported down the shoot.
    3) Light causes the movement of IAA to move from the light side to the shaded side of the shoot.
    4) Greater concentration of IAA builds up on the shaded side rather than light side.
    5) This causes shoot to elongate more.
    6) The shaded side of the shoot grows faster causing the shoot to bend towards the light.

    Edit: Is the point in bold the way growth is inhibited? Because the light causes it to move to the shaded side? :confused:
    Essentially, IAA stimulates the plant to grow. By being moved across, as per the bold point, this means the shaded side is stimulated to grow at a faster rate then the lit side. So the shaded side is stimulated to grow faster, but equally compared to a uniformly-lit plant, the brighter side would grow slower, so I guess that's where the idea of growth inhibition comes from.
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    I'm going to type this essay please mark it! Using the descriptors attached on the mark scheme at the end of the paper. Its so rubbish!

    Don't laugh.

    Question: Mean temperatures are rising in many parts of the world. The rising temperatures may
    result in physiological and ecological effects on living organisms. Describe and explain
    these effects.

    Increase int emperature is dealt with by living organisms in a variety of ways. Animals are seperated into two groups when considering thermoregulation. There are ectotherms and endotherms.

    Ectotherms will be greatly affectced by increase in heat as they get most of their heat from the enviroment. It will cause them to spend more time in the shade to prevent overheating.This may affect their ability to succesfully predate therefore decrease their chance of survival.Their enzymes will work faster so more metabolic activities such as protein synthesis occurs. This will require more energy which is difficult in the dark.

    Endotherms are able to control their temperature to an extent. The skin receptors will send impulses to the heat loss centre in the hypothalamus ,which sends impulses to the arteriaoles to dialate,hair to flatten and sweat glands to produce sweat which causes loss of heat through evaporation this keeps the blood cool. The blood is also kept cool as more of it is at the surface if the skin increasing surface area over which heat can be radiated out.

    Increase in temperature can also have numerous ecological effects. it can decrease habitats of animals adapted to living in the cold such as polar bears.As polar ice melts there is less space over which polar bears and mate and live.This will increase selection pressures of polar bears better adapted at living in the ocean.

    There will also be selection pressures within the plant community.Plants adapted to living in warmer conditions will be favoured,this is called directional selection. Plants that are adapted have features such as thin leaves to prevent water loss as the surface area to volume ratio is small. The main problem for plants is lack of water.

    Plants that are used for crops will decrease in yeild ,this will affect energy pyramids because all energy in energy pyramids enters by plants. This will cause a great reduction in energy transfered to higher tropic levels.The number of tropic levels of energy pyramids may also decrease because energy transfer is inefficient between levels.

    Plant yeilds will decrease because more of the energy assimilated will be used in respiration rather than stored.This is because the movement of enzymes will be faster as heat provides kinetic energy so more reactions occur per unit of time, these reactions require ATP which can only be produced through respiration.


    Please stop laughing!
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    (Original post by INeedToRevise)
    I have no idea on how growth is inhibited. If anything, I thought the plant grows more. This is my explanation for IAA:

    1) IAA causes plants to elongate.
    2) Cells in the tip of the shoot produce IAA. This is transported down the shoot.
    3) Light causes the movement of IAA to move from the light side to the shaded side of the shoot.
    4) Greater concentration of IAA builds up on the shaded side rather than light side.
    5) This causes shoot to elongate more.
    6) The shaded side of the shoot grows faster causing the shoot to bend towards the light.

    Edit: Is the point in bold the way growth is inhibited? Because the light causes it to move to the shaded side? :confused:
    Yes, It's inhibited as initially IAA is transported down to both sides of the shoot but the lights causes the movement of IAA from the light side to the shaded side and hence the amount of elogation on the light side decreases (growth in ibhibited). Note in the case above it is actually elogation in root cells and in roots IAA decreases growth unlike in shoot when it increases growth (elongation) and hence roots bend away from the light. ]
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    (Original post by Destroyviruses)
    Hi, about your muscle contraction notes.

    You've put that initially there is an ATP attached to the myosin head but according to the textbook. Initially it is ADP.The myosin moves and then the ADP is released. THEN ATP joins with myosin to remove it from the actin and but the head back in the "cocked" position. Then atpase hydrolysis ATP to ADP so its able to join to actin again.

    I just double checked on the textbook.
    Hmmmm...ok, it seems I got that a bit mixed up. Thanks for telling me, I'll go change that now. (:
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    Hi, would i be right in saying..

    The role of ATP
    - provides energy to disengage myosin head from actin
    - provides energy for 'power stroke'

    Role of Ca2+
    - To attach to troponin on the tropomyosin, (which moves to expose actin binding site)
    - To activate ATPase to provide energy for myosin head to return to original position??? Is this the same as disengaging the myosin head?
    Many thanks
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    "To provide energy" is a bit vague, you'd benefit more from saying "to produce ATP from ADP and an inorganic phosphate molecule"
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    (Original post by Destroyviruses)
    I'm going to type this essay please mark it! Its so rubbish!

    Don't laugh.

    Question: Mean temperatures are rising in many parts of the world. The rising temperatures may
    result in physiological and ecological effects on living organisms. Describe and explain
    these effects.

    Increase int emperature is dealt with by living organisms in a variety of ways. Animals are seperated into two groups when considering thermoregulation. There are ectotherms and endotherms.

    Ectotherms will be greatly affectced by increase in heat as they get most of their heat from the enviroment. It will cause them to spend more time in the shade to prevent overheating.This may affect their ability to succesfully predate therefore decrease their chance of survival.Their enzymes will work faster so more metabolic activities such as protein synthesis occurs. This will require more energy which is difficult in the dark.

    Endotherms are able to control their temperature to an extent. The skin receptors will send impulses to the heat loss centre in the hypothalamus ,which sends impulses to the arteriaoles to dialate,hair to flatten and sweat glands to produce sweat which causes loss of heat through evaporation this keeps the blood cool. The blood is also kept cool as more of it is at the surface if the skin increasing surface area over which heat can be radiated out.

    Increase in temperature can also have numerous ecological effects. it can decrease habitats of animals adapted to living in the cold such as polar bears.As polar ice melts there is less space over which polar bears and mate and live.This will increase selection pressures of polar bears better adapted at living in the ocean.

    There will also be selection pressures within the plant community.Plants adapted to living in warmer conditions will be favoured,this is called directional selection. Plants that are adapted have features such as thin leaves to prevent water loss as the surface area to volume ratio is small. The main problem for plants is lack of water.

    Plants that are used for crops will decrease in yeild ,this will affect energy pyramids because all energy in energy pyramids enters by plants. This will cause a great reduction in energy transfered to higher tropic levels.The number of tropic levels of energy pyramids may also decrease because energy transfer is inefficient between levels.

    Plant yeilds will decrease because more of the energy assimilated will be used in respiration rather than stored.This is because the movement of enzymes will be faster as heat provides kinetic energy so more reactions occur per unit of time, these reactions require ATP which can only be produced through respiration.
    Can someone mark this pleaseeee! Or do the same essay so I can compare and contrast, pretty pleasssssseeee.
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    (Original post by parallal)
    Hmmmm...ok, it seems I got that a bit mixed up. Thanks for telling me, I'll go change that now. (:
    How are you revising for the essay?
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    (Original post by cobra2k10)
    Only just over 2 and a half months now until the exam. Hows everyones revision going? This unit is going to be tough especially becuase it has the synoptic essay in it worth 25 marks!. I have attached the June 2010 and Specimen past papers with the mark schemes for revision purposes!!! There are no other actual BIOL5 papers available for this exam as it can only be taken in June. Enjoy

    REVISION NOTES: http://www.studentcreche.co.uk/resources/biol5.pdf
    Thanks for posting the resource links . I have a cluster of non-biology exams coming up and have only revised response.
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    (Original post by Destroyviruses)
    How are you revising for the essay?
    I'm trying to practice one essay every day. I time myself to make sure I can finish in about 40 mins. I was also thinking of looking over the AS book to refresh my memory on certain topics.

    What about you?
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    ive done a powerpoint on chapters 14 & 15 in the nelson thornes book for revision and i thought maybe some other people may find it useful.
    im really struggling with chapters 14-16 so let me know if there is anything else that can be added to it (or even if anything is wrong! lol)
    Attached Files
  1. File Type: pptx Genetics.pptx (92.1 KB, 1502 views)
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    (Original post by INeedToRevise)
    BIOL4 is out of 100 UMS :lies:
    HAH! whoops, which one was 140 UMS? was it 2? I can never remember the unit numbers! awkwarrddd :P
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    (Original post by Destroyviruses)
    Can someone mark this pleaseeee! Or do the same essay so I can compare and contrast, pretty pleasssssseeee.
    The first thing I'd say is that it would need to be longer, so try to go into more detail on some responses, also don't be afraid to use bullet points and diagrams, it doesn't all have to be prose, I realise I have kind of contradicted myself but parts that are just writing, try to be detailed on them, your range of topics appears to be good, but again more detail and try to get more length on it, it is really difficult to get a really good mark on a shorter essay, but the short amount of time we get for it is ridiculous!

    Good LUCCCKKKK
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    (Original post by Destroyviruses)
    Can someone mark this pleaseeee! Or do the same essay so I can compare and contrast, pretty pleasssssseeee.
    allsooo :P your use of scientific terminology is good!
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    (Original post by Tericon)
    Auxins

    I hate them and the CGP revision guide isn't helping.

    On phototrophism it says of the roots: 'IAA moves to [one] side - growth is inhibited so root bends away from the light.'

    How is growth inhibited..why? And if growth is inhibited, why is it able to bend? Surely bending is growth? :confused:
    Bending isn't technically growth, what is thought to happen is that the increased concentration of IAA elongates the cells by something to do with H+ making the cell walls more permeable to water so the cells take on more water and elongate.
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    (Original post by Destroyviruses)
    Can someone mark this pleaseeee! Or do the same essay so I can compare and contrast, pretty pleasssssseeee.
    I'll mark it later tonight probably and give you feedback. It looks good on the face of it.
 
 
 
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