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    (Original post by dush_2)
    Topic 7: Run for your life

    This topic is centred on the physiological adaptations that enable animals and humans, particularly sports people, to undertake strenuous exercise. It explores the links between an animal’s physiology and its performance. The topic summarises the biochemical requirements for respiration and looks at the links between homeostasis, muscle physiology and performance. It ends by looking at how medical technology is enabling more people to participate in sport, and by raising the issue as to whether the use of performance-enhancing substances by athletes can be justified.

    Topic 8: Grey matter

    The scene is set by considering how the working of the nervous system enables us to see. Brain imaging and the regions of the brain are considered. The topic also demonstrates how an understanding of brain structure and functioning is relevant to such issues as the response to stimuli, the development of vision and learning. It investigates how imbalances in brain chemicals may result in conditions such as Parkinson’s disease and its treatment with drugs are investigated. Students discuss the ethical issues raised by the Human Genome Project and the risks and benefits of using genetically modified organisms.



    Download the Scientific Article for June 2011

    how many times will you repeat this unit?
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    Can someone please explain this point on the spec... I'm not too sure about it.. thanks
    13 Explain how variations in ventilation and cardiac output enable rapid delivery of oxygen to tissues and the removal of carbon dioxide from them, including how the heart rate and ventilation rate are controlled and the roles of the cardiovascular control centre and the ventilation centre.
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    (Original post by Hibz93)
    Something thats been confusing me alot lately lol, whats the difference between accommodation and habituation?
    Are you serious?! You better read your book rather than write posts like this. The student room is no substitute for a book dude!
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    http://www.thestudentroom.co.uk/show...&postcount=105

    From the Unit 4 thread. ^ The book looks really good so may help someone on here.
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    hellow poeple does anyone no where i can get handouts/questions based on 6bio5??oh please poeple if you knoew let me no cuz i im sick from pastpapers they are not helpfull,most of them contain questions that is not in the sylabus at al.
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    (Original post by hassib)
    hellow poeple does anyone no where i can get handouts/questions based on 6bio5??oh please poeple if you knoew let me no cuz i im sick from pastpapers they are not helpfull,most of them contain questions that is not in the sylabus at al.
    http://vle.havant.ac.uk/Biology_web/..._questions.htm you can get questions from there, just scroll to the bottom and pick what you want
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    Not many core practicals but here they are and some ethical issues:
    Measuring the rate of oxygen uptake• Place 5g of organism (maggots) into the tube and replace the bung.
    • Introduce a drop of dye into the glass tube.
    • Mark the starting position of the fluid on the pipette tube with a permanent OHT pen.
    • Isolate the respirometer by closing the connection to the syringe and the atmosphere and immediately start the stop clock.
    • Mark the position of the fluid on the pipette at 1 minute intervals for 5 minutes. 6.
    • At the end of 5 minutes open the connection to the outside air.
    • Measure the distance travelled by the liquid during each minute (the distance from one mark to the next on your pipette).
    • If your tube does not have volumes marked onto it you will need to convert the distance moved into volume of oxygen used.
    • Record your results in a suitable table.
    • Calculate the mean rate of oxygen uptake during the 5 minutes.

    Outcome: Oxygen molecules are absorbed by the organism and used in respiration. The same number of carbon dioxide molecules are released but these are absorbed by the soda lime. This reduces the pressure inside the test tube (fewer molecules = lower pressure). Atmospheric pressure pushes the liquid along the tube, until the pressure in and outside the tube is equal. Oxygen is the final electron acceptor, and it eventually combines with hydrogen to make water. The carbon dioxide comes from the carbon dioxide released in the link reaction and the Krebs cycle as the carbohydrate is broken down

    Effects of exercise on tidal volume and breathing rate
    • A disinfected mouthpiece is attached to the tube, with the tap positioned so that the mouthpiece is connected to the outside air. (The subject to be tested puts a nose clip on, places the mouthpiece in their mouth and breathes the outside air until they are comfortable with breathing through the tube).
    • Switch on the recording apparatus and at the end of an exhaled breath turn the tap so that the mouthpiece is connected to the spirometer chamber. The trace will move down as the person breathes in.
    • After breathing normally the subject should take as deep a breath as possible and then exhale as much air as possible before returning to normal breathing.

    Outcome: The tidal volume is the volume of air breathed in and out in one breath at rest. The tidal volume for most adults is only about 0.5 dm3. Vital capacity is the maximum volume of air that can be breathed in or out of the lungs in one forced breath. Breathing rate is the number of breaths taken per minute. Minute ventilation is the volume of air breathed into (and out of) the lungs in one minute. Minute ventilation = tidal volume × rate of breathing (measured in number of breaths per minute). Some air (about 1 dm3) always remains in the lungs as residual air and cannot be breathed out. Residual air prevents the walls of the bronchioles and alveoli from sticking together. Any air breathed in

    Snail becoming habituated to a stimulus• Collect one giant African land snail, and place it on a clean, firm surface.
    • Allow the snail to get used to its new surroundings for a few minutes until it has fully emerged from its shell.
    • Dampen a cotton wool bud with water and firmly touch the snail between the eye stalks with the dampened cotton wool bud and immediately start the stopwatch.
    • Measure the length of time between the touch and the snail being fully emerged from its shell once again, with its eye stalks fully extended.
    • Repeat the procedure in step 3 for a total of 10 touches, timing how long the snail takes to re-emerge each time.
    • Record your results in a suitable table.
    • Present your results in an appropriate graph.

    Outcome: With repeated stimulation, Ca2+ channels in the presynaptic membrane become less responsive. Less Ca2+ crosses the membrane into the presynaptic (sensory) neurone. As a result less neurotransmitter is released into the synaptic cleft. This means that an action potential across the postsynaptic membrane is less likely. Fewer action potentials are produced in the postsynaptic motor neurone so less of a response is observed.

    Performance Enhancing Drugs Ethics
    For
    - Technological innovations are present in all sports, and at all levels so why view drugs differently
    - Some drugs do the same thing as non-drug method e.g. EPO and altitude training both increase red blood cell levels
    - Some people may need to take the drugs for health reasons.

    Against
    - Excessive use of the drugs may cause health issues
    - Sports nowadays have rewards such as large amounts of cash therefore use of drugs would be unfair

    Animal Testing Ethics
    For
    - Maximises the amount of good in the world
    - Animal welfare is more important as if we give animals rights then we would need their consent
    - Preferred for an animal to suffer rather than a human

    Against
    - We are not able to know how the animal feels
    - Some animal test are unnecessary such as cosmetic testing
    - Animals are unable to give their consent

    p.s. wasn't sure if i should include the locust one as it isn't a core practical but SNAB cn be dogey:eyeball:
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    (Original post by patrick93)
    http://vle.havant.ac.uk/Biology_web/..._questions.htm you can get questions from there, just scroll to the bottom and pick what you want
    Thanks for this. Do you know where to get the mark scheme for these?
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    (Original post by InItToWinItGetIt?)
    Thanks for this. Do you know where to get the mark scheme for these?
    nah i've tried to find them but no luck
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    (Original post by patrick93)
    nah i've tried to find them but no luck
    Aww that's a shame The questions look really good as well.
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    (Original post by StudentToday)
    Can some1 help me - confused :confused:

    Why does the heart respond to exercise? :

    Is it because of the increase of C02 therefore decrease in ph. Chemoreceptors detect this and then the hrt rate increases ect...?

    OR

    Is it because of increase/decrease in pressure detected by baroreceptors and stretch receptors ect...?

    In my revision guide it says tht exercise triggers a decrease in ph ad so the heart rate is increased, However, in my college text book it says that adrenaline decreases blood pressure at begginnig and so baraoresptors r not stimulated and so impulses sent down sympathetic and heart rate increases.
    Technically, it could be either.

    However we have been taught that generally an increase in heart rate is due to low pH and a decrease is due to high pressure.

    There are receptors for both pressure and pH. What we have been taught is that for exercise it will be the chemoreceptors. This is because during exercise, as you probably know CO2 levels rise causing pH to go down. This means more oxygen is needed for respiration so the heart pumps faster due to a nerve impulse from the sympathetic nerve.

    Post exercise it will most likely be responding to pressure. This is because CO2 levels will be lower due to the oxygen debt being repaid and then there will just be high pressure from a heart pumping harder.
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    (Original post by tkoki1993)
    its out already???!!??
    I dont think my teachers know that. I think I'll tell them tomorrow so I can talk about it freely in school without them realising there are ways to get ANY document that require the login details on the edexcel website
    Tell them anyway, I always find it amusing to get one over on them when, theyre all 'you cant get the mock paper because you require a log in blah blah' and then you tell them,
    you can just get it off another website where someones already uploaded it to ;D
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    (Original post by Rothers)
    Tell them anyway, I always find it amusing to get one over on them when, theyre all 'you cant get the mock paper because you require a log in blah blah' and then you tell them,
    you can just get it off another website where someones already uploaded it to ;D
    They didn't even know what results plus is -_-.
    The worst part is they kept arguing that the jan 11 past papers for salters chemistry were not on interchange.. but found them on tsr the next day :cool:
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    Good luck everyone with this unit, brings back memories me doing it last year
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    (Original post by thecdon)
    Good luck everyone with this unit, brings back memories me doing it last year
    Thanks, have you got any tips? How much AS stuff is on there etc etc.

    Tips for Unit 4 would be much appreciated as well
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    (Original post by InItToWinItGetIt?)
    Thanks, have you got any tips? How much AS stuff is on there etc etc.

    Tips for Unit 4 would be much appreciated as well
    I got 97% for Unit 5... my tip would be make sure you pay a lot of attention to the article...and always make sure you know action potentials inside out, they should be quite a bit on it.
    Unit 4 - make sure you know photosynthesis and the Calvin cycle inside out too!
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    (Original post by thecdon)
    I got 97% for Unit 5... my tip would be make sure you pay a lot of attention to the article...and always make sure you know action potentials inside out, they should be quite a bit on it.
    Unit 4 - make sure you know photosynthesis and the Calvin cycle inside out too!
    WOW, that's an awesome score, well done!

    I'm a bit worried about the article. How did you go about preparing for it? And did you get like these sample questions from the exam board, and if so how accurate are they?

    Yeah I finally got photosynthesis thanks largely to youtube lol. Learnt more in about 20mins off there then I did in all the lessons taught by my teacher :rolleyes: I haven't done any past papers yet, saving them for the last 10 or so days before the exam.
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    (Original post by InItToWinItGetIt?)
    WOW, that's an awesome score, well done!

    I'm a bit worried about the article. How did you go about preparing for it? And did you get like these sample questions from the exam board, and if so how accurate are they?

    Yeah I finally got photosynthesis thanks largely to youtube lol. Learnt more in about 20mins off there then I did in all the lessons taught by my teacher :rolleyes: I haven't done any past papers yet, saving them for the last 10 or so days before the exam.
    Cheers pal! My advice would be print off 2 copies of the article and annotate one with notes etc and then write down possible questions and then research the answers...it's basically comprehension in a way!
    Well done on your MEdicine offers by the way !
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    (Original post by thecdon)
    Cheers pal! My advice would be print off 2 copies of the article and annotate one with notes etc and then write down possible questions and then research the answers...it's basically comprehension in a way!
    Well done on your MEdicine offers by the way !
    Ah ok, I'll do that then. Do you remember if they asked a lot of synoptic stuff for Unit 4? Our school decided to make us sit both exams in June

    And thanks
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    (Original post by Hibz93)
    Something thats been confusing me alot lately lol, whats the difference between accommodation and habituation?
    Accomodation is when neurones do not respond to stimuli because of the resynthesis rate of the the vesicles that contain the neurotransmitters. This occurs when the discharge rate is greater than the rate of synthesis so the neurone 'fatigues'.
    Habituation is when the calcium ion channels in the pre-synaptic membrane become less responsive to a repeated stimulus due to its neutral effect. As a result, less Ca2+ ions pass into the pre-synaptic membrane and less neurotransmitter is released into the synaptic cleft so there is less depolarisation in the post-synaptic membrane. As the threshold level is not met, an action potential is not triggered.

    Just remember - Accomodation = synthesis rate and Habituation = calcium ion channels. And the rest should be easy to think through
 
 
 
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