C. Answer the following questions in detail. u Explain an activity to show the effect of saliva on lood. The digestive functions of saliva include moitning food, and helping 12. Explain the process of digestion in ruminants. 13. What are villi? Write its functions. 14. Draw a neatly labelled diagram of digestive system in humans.
Answers
Answer:
11. Experiment to show the effect of saliva on starch
Two test tubes were taken and were labeled A and B.
In test tube A one teaspoon full of boiled rice was kept.
In test tube B one teaspoon full of boiled rice which were chewed for 3-5 minutes were kept.
3-4 ml of water was added to both the tubes.
Then 2-3 drops of iodine solution was added to both test tubes A and B.
Observation:
The test tube A shows blue – black colour whereas test tube B does not show this colour.
Conclusion:
Since test tube B has boiled rice which were chewed for 3-5 minutes, the saliva present in mouth has acted upon starch to break down into sugars. So it does not show any colour in presence of iodine solution.
Boiled rice in test tube A has not been exposed to saliva, so starch is present which is indicated by blue-black colour on addition of iodine solution.
Answer:
Saliva contains an enzyme called as Amylase which breaks down the amylose in starch into amylopectin. ... But, the starch in the tube A was not chewed so the starch molecules are intact in it. The starch reacts with the iodine to give a bluish-black color. This indicates the action of saliva on starch
The digestive functions of saliva include moistening food, and helping to create a food bolus, so it can be swallowed easily. ... Saliva contains the enzyme amylase that breaks some starches down into maltose and dextrin. Thus, digestion of food occurs within the mouth, even before food reaches the stomach.
The digestion process in Ruminants begins by chewing and swallowing its food. Ruminants do not completely chew the food they eat, but just consume or gulp as much they can and then swallow the food. ... This cud produced is regurgitated back into the animal's mouth where they can be chewed again
Villi are small finger-like projections located in the walls of the small intestine. Their function is to increase the surface area in order to maximise the absorption of digested food. ... The lacteal absorbs fatty acids and glycerol and transports it away from the villi
