Class VII – Science

Chapter 2: Nutrition in Animals

Answer the following questions

1. Give an example of each of the following enzymes and state its function:
   1. A) Carbohydrase:
      Answer: Amylase – It breaks down starch into sugars.
   2. B) Proteases:
      Answer: Pepsin – It breaks down proteins into peptides.
   3. C) Lipases:
      Answer: Lipase – It breaks down fats into fatty acids and glycerol.
2. Principle of working of enzyme:
   Answer: Enzymes work on the principle of the lock and key mechanism, where the enzyme (lock) binds to the substrate (key) to catalyze a chemical reaction.
3. Special cells of liver that secrete bile juice:
   Answer: Hepatocytes
4. Special cells in the wall of the stomach that release hydrochloric acid:
   Answer: Parietal cells
5. Process of breaking down fat into smaller fat droplets by the action of bile juice:
   Answer: Emulsification
6. Name the glands and state their functions that take part in the process of digestion:
   Answer: Salivary glands (produce saliva), liver (produces bile), pancreas (produces digestive enzymes)
7. What are enzymes?
   Answer: Enzymes are biological catalysts that speed up the rate of chemical reactions in the body without being consumed in the process.
8. We should include roughage in our diet. Give a reason.
   Answer: Roughage (dietary fiber) helps in the proper functioning of the digestive system by aiding bowel movements and preventing constipation.