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AQA BIOL1 Biology Unit 1 Exam - 16th May 2011 watch

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    (Original post by EffKayy)
    advantages of tem
    *small objects can be seen, also internal details
    *higher resolution
    *small wavelength of electrons
    disadvantage
    *staining process has to occur, and yet it is still black and white
    *2d??
    *artefacts may occur from prep.
    *has to be in a vacuum
    *living specimens cant be tested
    *specimen has to be extremely thin

    SEM ADVANTAGE - specimen doesnt have to be thin.
    Yeah its 2d.
    Also SEMs can have colour or is 3d. I forgot which one.
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    Anyone know best way to achieve full marks, when asked to:
    -Describe graph
    -Explain graph

    and also whats the best way to answer an "Evaluate" question.

    Any help is much appreciated.
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    (Original post by ??????????????????)
    Risk factors:
    -Genetic
    -Smoking
    -Lack of exercise
    -High blood pressure


    Smoking causes tar build up in the arteries so they are smaller. This increases pressure. If there are arethroma's in the body, they can become dislodged from the pressure and end up clotting the Coronary arteries which reduced/stop blood flow to the heart so less oxygen. This causes the muscle tissues to die as they have no oxygen to respire with so no ATP produced to contract muscle to the heart tissue dies leading to a MI.
    yeah thats pretty much what i put aswell

    The risk factors involved in CHD include factors such as high blood pressure and high cholesterol, which can be caused by a diet high in salt or saturated fat. High blood pressure can cause the artery walls to weaken and form an aneurysm, whilst high blood cholesterol can result in an atheroma. Smoking contributes to CHD as the nicotine in tobacco increases adrenaline, which results in high blood pressure. The nicotine also has a ‘sticky’ effect meaning red blood cells stick together and form blood clots, which can restrict the blood flow and hence the supply of oxygen to the heart muscle. Smoking also increases carbon monoxide concentration which binds to haemoglobin irreversibly meaning insufficient oxygen is supplied to the heart muscle. These factors result in the heart muscle from dieing, therefore leading to a myocardial infarction.
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    (Original post by ??????????????????)
    Risk factors:
    -Genetic
    -Smoking
    -Lack of exercise
    -High blood pressure


    Smoking causes tar build up in the arteries so they are smaller. This increases pressure. If there are arethroma's in the body, they can become dislodged from the pressure and end up clotting the Coronary arteries which reduced/stop blood flow to the heart so less oxygen. This causes the muscle tissues to die as they have no oxygen to respire with so no ATP produced to contract muscle to the heart tissue dies leading to a MI.
    I don't think atheroma becomes dislodged? Atheroma is a built up of fatty substances and cholesterol in the lining of the artery, narrowing it. This increases the chance of an embolous getting jammed or a blood clot forming.
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    (Original post by canthardlywait)
    Anyone know best way to achieve full marks, when asked to:
    -Describe graph
    -Explain graph

    and also whats the best way to answer an "Evaluate" question.

    Any help is much appreciated.
    Describing should show the trends. Use terms like positive/negative correlation. Refer to the date. Eg at 0.4 concentration to 0.6 the rate of reaction increases then the gradient drops after 0.6 to 0.8.

    When explaining just say what caused the results.

    Evaluate needs both views. Go pros and cons.
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    (Original post by liviaaa)
    I don't think atheroma becomes dislodged? Atheroma is a built up of fatty substances and cholesterol in the lining of the artery, narrowing it. This increases the chance of an embolous getting jammed or a blood clot forming.
    Look up thrombosis.
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    (Original post by liviaaa)
    Some random Q:

    -Define disease

    -What's the biochemical test for a lipid?

    - What is the role of the nucleus?
    a disease is when an infection causes recognisable symptoms...
    i think
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    (Original post by canthardlywait)
    Anyone know best way to achieve full marks, when asked to:
    -Describe graph
    -Explain graph

    and also whats the best way to answer an "Evaluate" question.

    Any help is much appreciated.
    Describe, just say what you see - include figures!

    Explain - say why the described bit ^ happened

    Evaluate - the answer is normally no, and it's because it's only a correlation, not cause and effect, so may have been caused my other named factors. (May be yes for once though...)
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    (Original post by liviaaa)
    I don't think atheroma becomes dislodged? Atheroma is a built up of fatty substances and cholesterol in the lining of the artery, narrowing it. This increases the chance of an embolous getting jammed or a blood clot forming.
    an atheroma can rupture and increase the risk of a thrombosis, which can become dislodged and block other arteries

    ? i think
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    (Original post by ??????????????????)
    Look up thrombosis.
    Thrombosis is the process when a blood clot forms.
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    (Original post by emmaaa65)
    an atheroma can rupture and increase the risk of a thrombosis, which can become dislodged and block other arteries

    ? i think
    Yes the blood clot can become dislodged, but not the atheroma I don't think.
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    (Original post by liviaaa)
    Thrombosis is the process when a blood clot forms.
    They can become dislodged or rupture causing more blood clots or moving to other areas. If it moves to coronary arteries it will lead to M.I as it block the C. arteries.
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    Hey

    can anyone answer the question in the QP given at the beginning of the thread (11th Jan 2011)
    -QUESTION 4 (c) (iii)

    It's so confusing!!!!!!!
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    (Original post by liviaaa)
    Yes the blood clot can become dislodged, but not the atheroma I don't think.
    ahh yeah okay. the atheroma and thrombosis are two different things, but an atheroma can increase the risk of a thrombosis. i was starting to get all confused and ahhh lol
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    (Original post by canthardlywait)
    Anyone know best way to achieve full marks, when asked to:
    -Describe graph
    -Explain graph

    and also whats the best way to answer an "Evaluate" question.

    Any help is much appreciated.
    The others have answered your question, but in terms of the evaluate question try and think about if it was reliable, so the sample size, if there was a control, how many variables were changed. If it's about a drug or something for humans and it was only tested on animals, mention that too.
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    (Original post by liviaaa)
    Yes the blood clot can become dislodged, but not the atheroma I don't think.
    CGP says, the atheroma can rupture which damages artery walls giving it a rough surface. Platelets and firbin accumulate there making a blood clot which can block another artery or dislodge.
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    (Original post by anna258)
    Hey

    can anyone answer the question in the QP given at the beginning of the thread (11th Jan 2011)
    -QUESTION 4 (c) (iii)

    It's so confusing!!!!!!!
    I think it is 9.
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    (Original post by anna258)
    Hey

    can anyone answer the question in the QP given at the beginning of the thread (11th Jan 2011)
    -QUESTION 4 (c) (iii)

    It's so confusing!!!!!!!
    haha just did this paper!
    basically 1 molecule of water is formed from the condensation reaction between glucose and fructose (therefore making the sucorse molecule needed for olestra to form)
    thennnn just count all the letter Rs on the diagram as thats where fatty acids are formed by condensation reactions
    there are 8 Rs sooo

    8+1 = 9

    so the answer is 9
    i hoped that helped.. reading back it sounds really confusing
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    (Original post by liviaaa)
    Describe, just say what you see - include figures!

    Explain - say why the described bit ^ happened

    Evaluate - the answer is normally no, and it's because it's only a correlation, not cause and effect, so may have been caused my other named factors. (May be yes for once though...)
    In the jan2011 paper there was a mark for saying yes - there is a correlation or whatever, then two marks for no. so 3 in total. i forgot to say yes as i thought there would be no marks .
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    (Original post by EffKayy)
    advantages of tem
    *small objects can be seen, also internal details
    *higher resolution
    *small wavelength of electrons
    disadvantage
    *staining process has to occur, and yet it is still black and white
    *2d??
    *artefacts may occur from prep.
    *has to be in a vacuum
    *living specimens cant be tested
    *specimen has to be extremely thin

    SEM ADVANTAGE - specimen doesnt have to be thin.
    I think another advantage of SEM is that it produces a 3d image or is that also true for TEM?
 
 
 
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