Q. Write the function of the following in the
human alimentary canal:
(i) Saliva
(ii) HCl in stomach
(iii) Bile juice
(iv) Villi
(B) Write one function each of the following
enzymes:
(i) Pepsin
(ii) Lipase
[CBSE 2019]
Ans. (A) Function of given substances in
(i) Saliva:
(1) Saliva moistens the food so it can be
swallowed easily.
(2) Saliva contains the enzyme salivary
amylase that breaks some starches
into sugar.
(ii) HCl in stomach:
(1) The hydrochloric acid creates an
acidic medium which facilitates the
action of the enzyme pepsin.
(2) It also kills germs or pathogens.
(iii) Bile juice:
(1) It makes the acidic food coming
from the stomach alkaline, so as
to enable the action of pancreatic
enzymes.
(2) It contains bile pigments and bile
salts which carry out emulsification
of fats.
(iv) Villi:
(1) These are fnger-like projections
present in the inner lining of the
small intestines which increase the
surface area for absorption.
(2) In the large intestine villi absorb
water from the unabsorbed food.
(B) Function of enzymes is given below:
(i) Pepsin: It is found in gastric juice and
digests proteins found in ingested food.
(ii) Lipase: It digests the emulsified fats and
converts it to fatty acids and glycerol.
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