Digestion & Enzymes Intro
Introductory activities for SL Digestion.
This lesson begins with an experiment to model the hydrolysis of starch by amylase and the absorption of simple sugars using visking tubing. While students wait for diffusion there is an activity to use a textbook, Biodigital human or Zygote body as a research tool to answer some simple questions about the digestive system. The lesson finishes with a collaborative diagram drawing activity.
Lesson Description
Guiding Questions
What do we already know about digestion?
Why do we do digestion?
What are macromolecules and enzymes?
Activity 1 Practical activity to investigate the need for digestion.
Carry out the experiment on the Experiment to model simple digestion and absorption. worksheet below. This experiment takes time to progress so while waiting there is time for a few questions and Activity 2, 'The structure of the Digestive System'
Activity 2: Brainstorm / Research Activity - The structure of the digestive system
Students work together using their memories and some research for text book diagrams or text to construct a large diagram of the digestive system. The images in Zygotebody - 3D view of the human body may also be helpful.
Produce a large (A3 size or bigger), annotated diagram of the digestive system. Include the following structures -
- mouth,
- esophagus,
- stomach,
- small intestines
- large intestine,
- anus,
- liver,
- pancreas and
- gall bladder.
Open this next section to see an overview of the digestive system from BioDigital Human - Excellent detailed 3D viewer of the human body
Click the eye -->
![Image: screenshot of Biodigital human taken 2014](../../../ib/biology/images/flickr_cc_commercial_ok/06humans/biodigitalhuman_digestive.png)
Teachers notes
The experiment is a good beginning in this lesson which first asks the question Why do we need to digest food molecules. IB students often know something about the structure and function of the digestive system but they knowledge is fragmented and the big picture is sometimes unclear. This lesson hopefully will give students a clearer idea of the role of the digestive system and its enzymes, as well as a revision of its structure.
Be careful using student saliva. Although the risks can be minimised it is something that has been banned by some school authorities. Amylase enzymes, especially with a little added salt work well.
Biodigital Human and Zygote body are great resources but they are not strictly necessary for the second activity. They could make part of a homework task. Screen shots of different structures could be built into a report which annotated different parts of the digestive system.
A text book as a research tool in the second activity works well.