Q170 / 180 · AIIMS 2012 · Zoology

Assertion : Emulsification is necessary for the digestion of fats.Reason : After fats are emulsified, the action of enzyme amylase gets signi-ficantly increased.

  • A
    If both assertion and reason are true and reason is the correct explanation of assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of assertion
  • Correct answer
    C
    If assertion is true but reason is false
  • D
    If both assertion and reason are false

Solution

Being insoluble in water, fats and oils form large immiscible droplets in aqueous media but the enzymes which hydrolyse fats and oils (called lipases) are insoluble in fats and soluble in water. Therefore, lipases can act only on the water adjoining surfaces of fat droplets. Evidently, the larger the surface area of fat droplets, the greater is the action of the lipase on them. We know that the smaller the size of a droplet, the larger is its surface area relative to its mass. Thus lipases can digest fat in significant amounts only when large fat droplets are broken into tiny droplets to form a fine emulsion. This is the reason why emulsification is so necessary for the digestion of fats. Enzyme amylase, on the other hand, is a starch - hydrolysing enzyme which has no role in fat digestion.

Hence, the correct answer is option: 'C'.

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