Unit4- 3.2~ Mechanical and chemical digestion

Question 1

What is mechanical digestion?

Answer 1

Food physically broken down into smaller parts via chewing (mouth) and churning (stomach)

Question 2

What occurs during mechanical digestion?

Answer 2

• Mechanical digestion starts in the mouth, where teeth grind food into smaller pieces.
• The tongue mixes food with saliva, moistening it for easier swallowing.
• Swallowing moves food from the mouth to the oesophagus using complex muscle movements.
• The oesophagus moves food to the stomach.
• The stomach churns food with gastric juices, forming a semi-liquid mass called chyme

Question 3

What is chemical digestion?

Answer 3

Food broken down by chemicals like enzymes, acids and bile

Question 4

What occurs during chemical digestion?

Answer 4

• Chemical digestion begins in the mouth as amylase in saliva breaks down carbohydrates into simpler sugars.
• In the stomach, gastric juice with hydrochloric acid and pepsin begins protein digestion
• The stomach’s acidic environment denatures proteins, aiding enzyme digestion
• Chyme enters the small intestine, where bile from the gallbladder aids fat digestion, and pancreatic enzymes break down proteins, carbohydrates, and fats
• inal hydrolysis of these molecules occurs in the small intestine with the help of various enzymes secreted by its walls