SOLVED EXERCISE CHAPTER 01 BIOLOGY 10TH FBISE NEW BOOK

 

SOLVED EXERCISE BIOLOGY

CHAPTER 01

DIGESTIVE SYSTEM

 

1. What are the functions of saliva, gall bladder, pancreas, villus, bile, gastric gland, renin, HCl in stomach, and hepatic portal vein?

Answer:

• Saliva: Starts digestion of starch
• Gall bladder: Stores bile
• Pancreas: Produces enzymes
• Villus: Absorbs nutrients
• Bile: Breaks down fats
• Gastric gland: Secretes gastric juices
• Renin: Helps digest milk protein
• HCl: Kills bacteria and activates enzymes
• Hepatic portal vein: Carries blood from intestines to liver

2. Draw and label a longitudinal section of villus?

3. Name the structures that secrete enzymes necessary for human digestion?

Answer:

• Salivary glands
• Stomach
• Pancreas
• Small intestine.

4. Why is pepsin formed in inactive form pepsinogen?

Answer:

• To protect stomach tissues from being digested by the enzyme.

5. Why must digested food be distributed by blood in man and other animals?

Answer:

• To supply nutrients to all body cells for energy and growth digested food must enter into the blood.

6. How is chewing important to your digestion?

Answer:

• It breaks food into smaller pieces and mixes it with saliva for easier digestion.

7. What would happen if pancreatic juice did not reach your small intestine?

Answer:

• Digestion of fats, proteins, and carbohydrates would be incomplete in the absence of pancreatic juice.

8. Why papsin is unable to perform its enzymatic activity in the small intestine?

Answer:

• Because pepsin work best in acidic medium and in small intestine or duodenum the pH is basic which inactivate the pepsin enzyme.

9. Which parts of the digestive system can come in contact with bile?

Answer:

• Duodenum and small intestine.

10. Some cells of the stomach secrete mucus for protection of stomach wall. Suggest what the stomach wall needs to be protected against?

Answer:

• Against strong gastric juices like HCl and pepsin which can damage tissues.

11. Fill the enzyme table:

Name of Enzyme         Substrate         Product

Protease         Protein         Amino acids

Amylase         Starch         Sugars

Lipase             Lipids         Fatty acids & glycerol

12. Write the function of each type of teeth?

Answer:

• Incisors: Cutting

• Canines: Tearing

• Molars & Premolars: Grinding

13. Describe digestion in oral cavity?

Answer:

• Saliva breaks down starch
• Food is chewed and formed into bolus.

14. Differentiate between mechanical and chemical digestion?

Answer:

• Mechanical digestion: Physical breakdown (chewing)

• Chemical digestion: Breakdown by enzymes and acids