IGCSE Biology / Food and digestion

Teeth, chewing and peristalsis revision notes

Edexcel International GCSE Biology (4BI1), chapter 4: Food and digestion, specification point 2.28. Part of the full course.

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Chewing mechanically breaks food into smaller pieces without breaking molecules or chemical bonds, so enzymes can digest it faster. Peristalsis moves swallowed food along the oesophagus using two muscle layers.

More lessons in Food and digestion

• Carbohydrates, proteins and lipids
• Testing for starch, sugars, protein and fat
• The seven parts of a balanced diet
• What changes how much energy you need
• The parts of the digestive system
• Amylase, protease and lipase
• Bile, the liver and emulsifying fat
• The villus and absorption
• Practical: measuring the energy in a food sample