Question

Usman collected her saliva and mixed it with liquid A in the test tube In another test tube she took only liquid A after about 10 minutes, she added a few drops of iodin
solution to the mixture in the first test tube. It did not show any colour but when she
kreated the other test tube with iodine, a blue black colour appeared. Now answer the
following questions
10) What is the aim of this activity?
a) To show the action of salivary amylase on protein
Kb) To show the action of salivary lipase on starch
c) To show the action of salivary nuclease on starch.
(d) To show the action of salivary amylase on starch,
(ii) What is liquid A?
(a) Starch
(b) Lipid
(c) Alcohol
(d) Protein
(iii) Why did the first test tube not show any colour change with sodine while the
second one did?
(a) The first test tube did not show any colour change with iodine because iodine failed
to test
(b) The first test tube did not show any colour change with iodine because starch was
present in it.
(c) The first test tube did not show any colour change with iodine because starch was
not present anymore in it
(d) None of these
(iv) Which enzyme is responsible for such a result?
(a) Amylase
(b) Lipase
(c) Proteasc
(d) Nuclease
(v) Why does a piece of bread chewed for a long time
tastes sweet?
(a) A picce of bread chewed for a long time tastes sweet because the starch is broken
down by salivary amylase to maltose sugar
(b) A piece of bread chewed for a long time tastes sweet because the starch got
emulsified by salivary amylase to fructose
(c) Starch is sweet in taste
(d) A piece of bread chewed for a long time tastes sweet because the starch is broken
pown by salivary amylase to fatty acids​

Answer 1

Answer:

The process of digestion begins in the mouth. Saliva secreted by the salivary glands can convert starch into sugars. When some boiled rice is taken in a test tube and a few drops of iodine solution are poured into it, we see violet colour. But when we add some boiled rice with saliva it will not give violet colour because saliva contains amylase which converts the starch into the simple sugar. Thus, on the addition of iodine solution, it does not give violet but reddish-brown colour.