4. What are villi? What is their function in the digestive system? 5. The sugar glucose is absorbed into the bloodstream in the small intestine. Where is glucose transported to and what chemical reaction is it involved in?
6. A body builder will eat a special diet to build up muscle. Suggest the types of food that he or she would eat and explain your choice.
7. Why do you think the large intestine is named ‘large’ when it is shorter than the small intestine?
8. How do the bacteria in our large intestine benefit us? 9. Explain the importance of pancreatic juice being alkaline.
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Thinking and Investigating 1. The stomach is lined with a thick layer of mucus. Why do you think this is important?
2. Enzymes work to their maximum efficiency when they have optimum (ideal) conditions. They are sensitive to temperature and other factors. (a) What do you think the optimum temperature for enzymes in the human body is? (b) Do you think that a plant enzyme would work at its highest efficiency at this temperature? Explain your answer.
3. Heartburn occurs when some of the acid from the stomach moves into the oesophagus. (a) Why do you think this causes pain? (b) How might you relieve the symptoms of heartburn?
4. How do you think food reaches an astronaut’s stomach when he or she is floating in zero gravity?
5. A child picks up a piece of chocolate that he dropped on the floor and eats it. The child does not get sick. How does the digestive system deal with the ingestion of germs?
