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    Is the glyscosidic bond around just the oxygen and between the two carbons of the two adjacent monosaccharides, or does it involve the two carbons as well?

    Also. What is the function of the RER? Because my teacher told me that is used for protein synthesis. But, isn't that the function of ribosomes?

    Can I just say that, the Rough endoplasmic reticulum folds and processes proteins produced at the ribosomes that covers it, and then provides the pathway for the transport of these proteins around the cell?

    Many thanks,

    Aillias.
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    A single glycosidic bond in a polysaccharide comprises the carbon of one monosaccharide and the oxygen from the adjacent monosaccharide - it's not a bond if there's only one atom.

    Ribosomes are used to synthesise soluble proteins in the cytosol whereas the proteins synthesised by ribosomes attached to the RER are secretory proteins i.e. membrane (e.g ER or cell membrane) or extracellular proteins.
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    (Original post by onefour)
    A single glycosidic bond in a polysaccharide comprises the carbon of one monosaccharide and the oxygen from the adjacent monosaccharide - it's not a bond if there's only one atom.

    Ribosomes are used to synthesise soluble proteins in the cytosol whereas the proteins synthesised by ribosomes attached to the RER are secretory proteins i.e. membrane (e.g ER or cell membrane) or extracellular proteins.
    So, in the B1 Exam, if it asks you to draw around a glyscosidic bond, how would you draw it?

    And thanks for the confirmation of what a ribosome is. But I still don't get what the RER does. You didn't say what a RER does.
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    (Original post by Aillias)
    So, in the B1 Exam, if it asks you to draw around a glyscosidic bond, how would you draw it?

    And thanks for the confirmation of what a ribosome is. But I still don't get what the RER does. You didn't say what a RER does.
    In the exam if you are asked to draw around where the bond forms if there are 2 monosaccharides, draw around the OH of 1 molecule, and the H of the other (the ones at the bottom). If you are asked to draw around the glycosidic link you draw around the oxygen as on the AQA spec you are only expected to know the simple structure of Glucose which doesn't have the carbons drawn on.
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    (Original post by SHABANA)
    In the exam if you are asked to draw around where the bond forms if there are 2 monosaccharides, draw around the OH of 1 molecule, and the H of the other (the ones at the bottom). If you are asked to draw around the glycosidic link you draw around the oxygen as on the AQA spec you are only expected to know the simple structure of Glucose which doesn't have the carbons drawn on.
    If you are asked to draw around the glycosidic link you draw around the oxygen as on the AQA spec you are only expected to know the simple structure of Glucose which doesn't have the carbons drawn on.

    Just to clarify, just oxygen, NO carbons of either monosaccharide? that's different to the first guy's comment.

    Oh, and could you phrase the function of a RER into an AQA model answer?

    Many thanks,

    Aillias
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    I teach AS Biology and this is how it is in the textbook and what I think is correct:

    The first person is correct - scientifically the bond is between the C-O but on the exam mark scheme the above diagram is correct.

    I haven't taught the cell structure part of the spec but from my understanding the RER synthesises proteins (which is why it has numerous ribosomes attached to it) by modifying the polypeptide chain using enzymes or adding carbohydrates. These proteins are then exported using the Golgi body. So the proteins are for export.
    I can't give you the perfect answer as I have not looked at past papers/mark schemes for this part of the unit as I share the class with another teacher.
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    (Original post by SHABANA)
    I teach AS Biology and this is how it is in the textbook and what I think is correct:

    The first person is correct - scientifically the bond is between the C-O but on the exam mark scheme the above diagram is correct.

    I haven't taught the cell structure part of the spec but from my understanding the RER synthesises proteins (which is why it has numerous ribosomes attached to it) by modifying the polypeptide chain using enzymes or adding carbohydrates. These proteins are then exported using the Golgi body. So the proteins are for export.
    I can't give you the perfect answer as I have not looked at past papers/mark schemes for this part of the unit as I share the class with another teacher.

    Thanks for the heads up on how to draw it. The AQA book is WRONG.

    And I've asked my teacher about the RER function, and she says that it just folds and processes the proteins formed in the ribosomes that covers the RER, which the RER then provides a pathway for the transport of these proteins around the cell.

    Thanks again,

    Aillias
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    (Original post by Aillias)
    Thanks for the heads up on how to draw it. The AQA book is WRONG.

    And I've asked my teacher about the RER function, and she says that it just folds and processes the proteins formed in the ribosomes that covers the RER, which the RER then provides a pathway for the transport of these proteins around the cell.

    Thanks again,

    Aillias
    From my understanding, the RER doesn't fold polypeptide chains, it just packages the synthesised polypeptide chain into a small vesicle which fuse to form the forming face of the golgi body (via microtubules) and it is the golgi which folds it into secondary, tertiary, quarternary or adds polysaccarides depending on the desired function them packages for export or lysosomes
 
 
 
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