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Tuesday, September 06, 2005

 

BIOLOGY - Nutrition in Man

~nutrition in man~

WE EAT EVERYDAY(unless anorexic) ARE WE REALLY WHAT WE EAT? (i eat sweets :))

Why do we need food?
provide energy
synthesize new protoplasm
- growth and repair of worn out parts
- reproduction
prevent deficiency diseases
__________________

Carbohydrates

monosaccharides - glucose, fructose, galactose
disaccharides - maltose, lactose, sucrose
polysaccharides - starch, cellulose, glycogen


  • energy source
  • supporting structures (cellulose cell wall in plant)
  • energy storage (starch grains in plant cells, glycogen in animal cells)
  • converted into other organic compounds
  • formation of nucleic acid
  • synthesize lubricants (mucus)
  • produce nectar
    • __________________

    Glycogen- found in liver, muscles
    - glucose molecules condense to form highly branched chains of glucose units

    -----------------------

    Glycogen and Starch are used as Storage Materials because..........


  • insoluble in water
    • >>> do not change osmotic pressure
  • large molecules
    • >>> unable to diffuse through membranes

  • easily hydrolysed
    • >>> can give energy when needed

  • compact shape
    • >>> occupy less space

    ------------------------------
    Test for Reducing Sugars

    BENEDICT'S TEST
    - solution(which contains reducing sugars) would change from BLUE to GREEN/YELLOW to ORANGE-RED precipitate
    _______________________

    Fats

    Saturated
    - lack double bonds
    - cholesterol

    Unsaturated
    - one or more double bonds
    - oleic acid (olive oil)

    --------------------------

    Test for Fats

    Using filter paper
    - translucent spot seen on filter paper

    Ethanol emulsion test
    - add ethanol to solution with fats
    - colourless solution obtained (fats dissolves in ethanol)
    - add water
    - white emulsion obtained (fats cannot dissolve in water)
    - heat given out

    --------------------------

    Functions of Fats

    [I'LL BE BACK.]


    # we mugged! @ 5:39 AM
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