6.1: Digestion and absorption
Teaching time: 3 hours Practical time: 1 hour (visking tubing models of gut digestion)
Demos: Oil & Water and washing up liquid for emulsification
Exercise 1: Study the quizlet deck via "learn" to gain fluency with the vocabulary of this section
Key vocabulary
Prior learning and retrieval practice
Review topic 2.1 molecules to metabolism
Review topic 2.5 enzymes
the digestive system
Essential idea: The structure of the wall of the small intestine allows it to move, digest and absorb food.
Exercise 2: Read your textbook, explain in your own words how the small intestine moves, digests and absorbs food.
A1: Processes occurring in the small intestine that result in the digestion of starch and transport of the products of digestion to the liver.
Exercise 3: Explain in your own words how starch is digested and absorbed by the digestive system, and then transported to the liver.
Structure of the digestive system
S1: Production of an annotated diagram of the digestive system.
Exercise 4: Study this quizlet diagram of the digestive system using "learn".
U1: The contraction of circular and longitudinal muscle of the small intestine mixes the food with enzymes and moves it along the gut.
S2: Identification of tissue layers in transverse sections of the small intestine viewed with a microscope or in a micrograph. Guidance: Tissue layers should include longitudinal and circular muscles, mucosa and epithelium.
Exercise 5: Study this quizlet diagram of the structure of the tissue layers in the digestive system.
Digestion
U2: The pancreas secretes enzymes into the lumen of the small intestine.
U3: Enzymes digest most macromolecules in food into monomers in the small intestine.
Guidance:
Students should know that amylase, lipase and an endopeptidase are secreted by the pancreas. The name trypsin and the method used to activate it are not required.
Students should know that starch, glycogen, lipids and nucleic acids are digested into monomers and that cellulose remains undigested.
Exercise 6: Make a table with the following column headings "Enzyme" "Secreted from" "Substrate" and "Product". Find the relevant information for the following enzymes:
Amylase
Maltase
Lipase
Endopeptidase
Absorption
U4: Villi increase the surface area of epithelium over which absorption is carried out.
U5: Villi absorb monomers formed by digestion as well as mineral ions and vitamins.
U6: Different methods of membrane transport are required to absorb different nutrients.
Exercise 7: Complete this Quizlet deck to familiarise yourself with the structure of a villus
Models in Science
A2: Use of dialysis tubing to model absorption of digested food in the intestine.
NoS: Use models as representations of the real world—dialysis tubing can be used to model absorption in the intestine. (1.10)
