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Biology Help

  1. Feb 20, 2005 #1
    We did this experiment where we had to burn nuts. And I did not get these questions, can someone help me with them?

    1) What part of the nut is burned? (is it the fat part??)
    2) What is nut oil composed of?? (is it fat??)
    3) Why does "nut" contain more energy than carbs or protein?? (???)
     
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  3. Feb 20, 2005 #2

    iansmith

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    What is the energy/dietary content of your type of nuts? What is the maine ingredient for energy.

    As for oil content, it is basicly Carbon and hydrogen and the number of carbon will have an impact on the potential energy of the molecule.
     
  4. Feb 20, 2005 #3
    What is the energy/dietary content of your type of nuts?
    695 kcal/100g??
    What is the maine ingredient for energy.
    fat, oil?
     
  5. Feb 20, 2005 #4

    iansmith

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    I was talking more in the line of the follwing

    Walnuts
    Protein 17.148 g
    Total lipid (74.244 g
    Carbohydrate 22.008 g
    Fiber 5.760 g

    http://www.moondragon.org/nutrition/foodguide/nutwalnut.html

    That give you what part could be burned.

    Satured fatty acid, unsaturated, cholesterol, etc.
     
  6. Feb 20, 2005 #5
    I think I got it now. Thank You :)
     
  7. Feb 20, 2005 #6
    Yep the oil is fat ( or triglycerides).


    The nut "contains" more energy (releases more energy) because chemically, it has the most potential to create C=O bonds (carbon double bond to oxygen) in [tex]CO_2[/tex], which releases the most energy (exothermic).
    This process in oxidation.
    Carbohydrates are already partially oxidised, because they already contain many -OH bonds (have a look at the molecular structure of, say, glucose), so they don't release as much energy as fats.
     
  8. Feb 21, 2005 #7
    Do priteins also contain -OH bonds ??
    Thanks
     
  9. Feb 21, 2005 #8
    I see where you're coming from.
    But actually proteins don't really. Fats release more energy (39.4 kJ/g) than proteins (17.9 kJ/g) and carbohydrates (15.8kJ/g) - they have very long chains of -C-H bonds and have more potential to make CO2 (and H2O. as oxidation produces water and carbon dioxide) as I mentioned above. In my posts I should've add a bit more detail and mentioned that the carbohydrates bonds are -C-O-H bonds (ie they have some CH bonds too, but they are partially oxidised). Proteins have a few -C-H bonds in comparison to fats.

    *data was from my biology book, and as you can see carbohydrates and proteins are actually similar in releasing energy.
     
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