Life processes
1. What is the role of the acid in our stomach?
Ans: This acid serves the following functions:
- The hydrochloric acid creates an acidic medium that facilitates the action of the enzyme pepsin
- Provides an acidic medium for protein digestion.
- Kills bacteria entering through food and prevents infection
2. What is the function of digestive enzymes?
Ans: Digestive enzymes convert the food into smaller molecules that your tissues, cells, and organs utilize for many metabolic functions. It takes some time to complete this process and results in amino acids, glycerol, fatty acids, and simple sugars. When you chew and break food into small pieces, special enzymes produced in different parts of your digestive region start acting to complete the process.
3. How is the small intestine designed to absorb digested food?
Ans: The digested food is taken up by the walls of the intestine. The inner lining of the small intestine has numerous finger-like projections called villi which increase the surface area for absorption. The villi are richly supplied with blood vessels that take the absorbed food to each and every cell of the body, where it is utilized for obtaining energy, building up new tissues, and the repair of old tissues.
4. How are fats digested in our bodies? Where does this process take place?
Ans: The food coming from the stomach is acidic and has to be made alkaline for the pancreatic enzymes to act. Bile juice from the liver accomplishes this in addition to acting on fats. Fats are present in the intestine in the form of large globules which makes it difficult for enzymes to act on them. Bile salts break them down into smaller globules increasing the efficiency of enzyme action.
5. What is the role of saliva in the digestion of food?
Ans: The saliva contains an enzyme called salivary amylase that breaks down starch which is a complex molecule to give sugar. The food is mixed thoroughly with saliva and moved around the mouth while chewed by the muscular tongue.
6. Explain digestion in amoeba with the help of a diagram.
Ans: Amoeba shows the holozoic nutrition. It means that the Amoeba consumes the whole food through endocytosis and digests the food inside the cell within the food vacuole. The digestion process can be described as:
- Ingestion- Amoeba moves towards the food by making pseudopodia. The pseudopodia surround the food particle and fuse to form the food vacuole, which is then taken inside the cytoplasm.
- Digestion- The food vacuole is combined with lysosomes that contain the hydrolytic enzymes. These enzymes perform the breakdown of food particles.
- Absorption- The digested food is then absorbed directly into the cytoplasm from where it will be distributed to the different organelles.
- Assimilation- The absorbed food is used for the generation of energy. The excess amount is stored in the form of glycogen and lipids in the cytoplasm.
- Excretion- The undigested food in the food vacuole is excreted out of the cell as the food vacuole fuses with the cell membrane and performs exocytosis.
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