Use models as representations of the real world—dialysis tubing can be used to model absorption in the intestine. (1.10)
Models allow scientists to represent an idea that is difficult, or impossible to experience directly. By their nature they are simplifications of the real world processes they describe, but they are still extremely useful as a means of explaining processes, making predictions, testing hypotheses and analysing data. Think of the importance of models of climate change or fisheries populations – these models have direct impacts on economics, politics and society.
In 6.1 we are discussing the use of models in the digestive system. A classic middle-school demonstration is to use visking, or dialysis, tubing to demonstrate the workings of the digestive system. An example experiment using starch, iodine and Benedict’s solution shows how this might work. The inside of the model gut originally contains both starch and glucose. However, testing over time shows that after 15 minutes, the gut still contains starch, however the liquid outside the “gut” tests positive for glucose. The movement of glucose out of the gut and into the surrounding fluid, while the larger starch molecules stay behind, helps demonstrate the need to reduce the size of polysaccharides before they can be absorbed and used by the body.
It would be useful to review the different NOS statements on models and develop some common ideas about the use of models in biology. Turn each statement into a question using an appropriate command term and try to develop some short-answers. For example:
- NOS statement for 6.1 – Use models as representations of the real world—dialysis tubing can be used to model absorption in the intestine.
- This becomes: Outline how dialysis tubing can be used to model absorption in the intestine (3).
“Evaluating Visking Tubing As A Model For A Gut | Nuffield Foundation”. Nuffieldfoundation.org. N. p., 2016. Web. 11 Dec. 2016.
“Scientific Modelling “. Sciencelearning Hub. The University of Waikato. 2016. Web. 9 Dec. 2016.