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

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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!!!!!!!
    It's 9. Look at the diagram above, count how many R groups there are 8, and plus the X bond. 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!!!!!!!
    Water molecules are produced from condensation reactions. So one molecule of water would be produced when the glucose and frutose join by condensation to produce sucrose. At the top of the question, it says that the fatty acid 'R' chains attach by condensation. You will notice that there are 8 fatty acid chains that have attached to the molecule, again by condensation. One molecule of water is produced each time one of the fatty acid chains attaches to the sucrose molecule.

    I'll let you do the maths, hope that helped
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    (Original post by EffKayy)
    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 .
    Okay thankss
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    (Original post by emmaaa65)
    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
    THANKS SO MUCH xxxx
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    Whoever was talking about Cholera before, I found a passage off one of the exam papers, so will be the correct info.

    Cholera is a water-borne disease. It is caused by a bacterium. The bacterium
    produces a toxin which acts on the epithelial cells of the small intestine and causes
    changes in membrane permeability. The cholera toxin affects the movement of ions
    through the intestinal wall. It causes the loss of chloride ions from the blood into the
    5 lumen of the small intestine. This prevents the movement of sodium ions from the
    lumen of the small intestine into the blood. The resulting high concentration of
    ions causes diarrhoea.
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    (Original post by emmaaa65)
    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
    WOW! Thanks! I couldn't figure this out too, I wrote 2 in jan 2011 because i didn't count the Rs at the top!
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    can someone explain the co-transport system of glucose by active transport using the na-k pump?? please...
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    (Original post by oHellno)
    Water molecules are produced from condensation reactions. So one molecule of water would be produced when the glucose and frutose join by condensation to produce sucrose. At the top of the question, it says that the fatty acid 'R' chains attach by condensation. You will notice that there are 8 fatty acid chains that have attached to the molecule, again by condensation. One molecule of water is produced each time one of the fatty acid chains attaches to the sucrose molecule.

    I'll let you do the maths, hope that helped
    Thanks for the explanation
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    how can you revise for how science works questions?
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    (Original post by gunit123)
    can someone explain the co-transport system of glucose by active transport using the na-k pump?? please...
    Sodium is actively transported out of the epithelial cells and into the blood via the sodium pump. This estalishes a concentration gradient as the concentration of Na in the cells is lower than the concentration in the lumen. So the Na in the lumen can move into the cells by facilitated diffusion (down the conc gradient), however they couple with a glucose molecule and enter the cell via the co-transporter. Glucose moves against the concentration gradient as there is a higher concentration in the cell, but to ensure maximum absorption it must enter with the sodium. So it's an indirect form of active transport as it relies on the Sodium ions.

    The glucose in the epithelial cells then moves into the blood capillary by facilitated diffusion across a protein channel.
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    (Original post by oHellno)
    Water molecules are produced from condensation reactions. So one molecule of water would be produced when the glucose and frutose join by condensation to produce sucrose. At the top of the question, it says that the fatty acid 'R' chains attach by condensation. You will notice that there are 8 fatty acid chains that have attached to the molecule, again by condensation. One molecule of water is produced each time one of the fatty acid chains attaches to the sucrose molecule.

    I'll let you do the maths, hope that helped
    hahaa, another question too, if you don't mind...
    How did you do QUESTION 5.b) from the same paper? :confused:
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    (Original post by jessplease)
    how can you revise for how science works questions?
    Is that stuff like questions about MRSA and real life HPV vaccines etc?
    If so then always read the passage carefully, it mostly gives you the clues and answers there.
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    (Original post by gunit123)
    can someone explain the co-transport system of glucose by active transport using the na-k pump?? please...
    basically sodium is actively transported out of the epithelial cells into the blood by the na-k pump using ATP. this causes the concentration of sodium ions in the lumen of the small intestine to be greater than that of the epithelial cells. sodium couples with glucose and travels along a concentration gradient through a co-transporter protein carrier. glucose then moves along a concentration gradient into the blood by facilitated diffusion through a protein carrier.
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    (Original post by gunit123)
    can someone explain the co-transport system of glucose by active transport using the na-k pump?? please...



    (Lumen)Glucocse and Na+
    ================================ =
    (Epithelial)Na+
    ================================ =
    (Blood) K+

    Sodum-pottassium pump pumps Na ions into the blood and pottassium into the epithial. This lowers the conentration of Na ions in the epithelial so Na will enter. However it is attatched to glucose and uses faccilitated diffusion which is still pasive. They use sodium-glucose co-transporter proteins. Glucose enters the epithelial. Then enters the blood through a protein channel.
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    (Original post by jessplease)
    how can you revise for how science works questions?
    To be honest , you cannot revise for them. They can ask any question they like that you wont expect. However, there are some key terminology you need to know such as reliability ,accuracy and biasness and also correlation does not mean causation. If there is a vague question just analyse the graphs closely as possible taking in to consideration units used, who did it and if there are anomalies. Oh another tip is on some describe question with results on a table the most probably answer for one mark is plot a graph.
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    (Original post by anna258)
    hahaa, another question too, if you don't mind...
    How did you do QUESTION 5.b) from the same paper? :confused:
    Don't know how well I can explain this, but...

    If he used 20cm^3 of his solution it would have had a conc of 1mol, he wanted it to be 0.2 mol. So if you divide through by 5, he would have used 4cm^3 of the solution and 16cm^3 of water making up 20cm^3.
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    (Original post by anna258)
    hahaa, another question too, if you don't mind...
    How did you do QUESTION 5.b) from the same paper? :confused:
    20cm3 = 1 mol

    So

    4cm3 = 0.2 mol (divide it by 5)

    As there is 4cm3 of NaCl, there must be 16cm3 of water, to make it up ot 20 cm3.
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    what do antibodies do? and whats the difference between an antibody and a pathogen and therfore why are they destroyed seperatly?
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    I'm starting my revision now...

    I was wondering whether we would have to discuss cytokines for the humoral immunity. Or is that a step to high for AS?
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    (Original post by RG1994)
    what do antibodies do? and whats the difference between an antibody and a pathogen and therfore why are they destroyed seperatly?
    Antibodies clump bacteria together by binding to the antigens. They then can't enter cells as they are too big to fit through the membranes. Also easier to ingest fo WBC.
 
 
 
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