2.2 Nutrition in Animals

• Digestion of different types of food in each region of the digestive system
• Adaptations of parts of the human digestive system
• Experiments on food tests

• describe the digestion of different types of food in each region of the digestive system
• explain the adaptations of parts of the human digestive system
• perform experiments to determine the presence of different nutrients in food
• appreciate the role of different parts of the digestive system

“What is the importance of breaking down food?”

“Why does the stomach not digest itself?”

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1. Digestion along the gut
   40 min · 2 practice tasks · quiz
   What happens to food at each stage, why it must be broken down at all, and the enzymes that do it.
2. Adaptations of the gut, and testing food
   40 min · 2 practice tasks · quiz
   Why the small intestine is shaped as it is, and how to find out what a food contains.
3. Enzymes of the gut
   40 min · 2 practice tasks · quiz
   Which enzyme works where, why each needs a particular pH, and why boiling a meal does not digest it.
4. Teeth and physical digestion
   40 min · 2 practice tasks · quiz
   How four tooth shapes start digestion, and why chewing is not a chemical change.
5. Carbohydrate digestion along the gut
   40 min · 2 practice tasks · quiz
   What happens to starch in ugali from the mouth to the blood, enzyme by enzyme.
6. Protein digestion and the stomach wall
   40 min · 2 practice tasks · quiz
   How beans and meat become amino acids, and the three protections that stop pepsin digesting you.
7. Fat digestion and the work of bile
   40 min · 2 practice tasks · quiz
   Why fat waits until the duodenum, what bile actually does, and where the products go.
8. Absorption, assimilation and egestion
   40 min · 2 practice tasks · quiz
   What enters the blood, what the body builds from it, and why faeces are not excretion.
9. Adaptations of each region of the gut
   40 min · 2 practice tasks · quiz
   How mouth, oesophagus, stomach, intestines and sphincters are each built for one job.
10. Investigating nutrients in Kenyan foods
    40 min · 2 practice tasks · quiz
    Apply the four food tests to a real plate, read mixed results, and connect them to digestion.