Pancreatic Enzymes and Diseases I
Lab Assignment
In this lab we'll be taking a look at the process of digestion in animals, focusing on the role of the pancreas and pancreatic enzymes. The entire activity is divided between two lab assignments; for the second lab assignment you will make use of your answers and feedback from your TA on the first. That way, you will be able to make sure that you are on the right track, and then build on your initial understanding of this system. The work required in the two lab assignments is outlined below.
1. Read the literature packet (provided) and answer questions to establish your understanding of the role of enzymes in digestion generally, and the roles and interactions of pancreatic enzymes in particular.
2. Develop a diagram illustrating the process of trypsin activation.
3. Use your understanding from the literature packet to design a simple experiment to answer a research question about pancreatic enzyme action.
1. Based on Part I and your TA's feedback, use your knowledge of digestive enzymes to address some more complex questions.
2. Revise your diagram from Part I as needed, and expand the diagram to include two more digestive enzymes. Create a second diagram showing our current understanding of pancreatitis, with the goal of using these two diagrams to explain to a friend the function and malfunction of the pancreatic digestive enzyme system.
3. Revise your experimental design, and write predictions for the observed results.
By the end of the two labs related to this topic you should be able to...
1. Describe the role of enzymes in general and pancreatic enzymes in particular in animal digestion.
2. Discuss why disease models are useful for understanding normal systems, with specific reference to pancreatitis and pancreatic enzymes.
3. State a testable hypothesis and design a simple experiment to address it, distinguishing between hypothesis and prediction, direct and indirect observation, and controls and treatments.
This is an overview of what you will do to complete this lab; full instructions are included in the assignment document.
Download the Pancreatic Enzymes and Diseases.pdf literature packet from the assignment dropbox for this lab. The packet consists of selected readings from three sources: a credible medical information website (Mayo Clinic 2011), selections from a 2006 article published in the medical journal Endocrinology and Metabolism Clinics of North America (Ruthenbürger et al. 2006) , and selections from a 2012 article in the veterinary medicine journal Topics in Companion Animal Medicine (Westermarck and Wilberg 2012).
Together, these sources describe two medical conditions that can affect the pancreas. In biology and medicine, we often study malfunctioning systems (such as genetic mutations or diseases) to learn more about how properly functioning systems work. Learning how diseases develop can be a good way to understand how the healthy system normally functions; in these readings, you will learn how the pancreas produces powerful digestive enzymes in an inactive (zymogen) form, which normally assume their active form in the small intestine through the action of other enzymes. When this process goes wrong, damage to the pancreas can result, and treatment can be required.
In your assignment document for this lab, answer the questions about the information in the literature packet.
You will construct a diagram showing the process of trypsin activation, but don't worry - you don't need to be a graphic design artist to produce a decent diagram. There are a number of options for creating your diagram:
1. Draw it on paper and photograph it or scan it.
2. Use an application such as DrawFree for iPad.
3. Use a web-based application such as Diagramly.
4. Use the 'Insert Shapes' function in PowerPoint on a blank slide; once you've built up the diagram, group all of your shapes together and use the Save As Picture function to capture your diagram as a single image.
You may be aware of other, similar applications. In any case, save your image as a .jpg file, incorporate your surname into the filename, and either insert your image into the assignment document or upload it separately when you submit.
By this point in the lab you will be familiar with the functions and relationships of some key digestive enzymes produced by the pancreas, and you can use your understanding to develop a simple experiment to investigate some aspect of this system. Included in the lab assignment document is a list of possible enzymes to use in your study, two food substrates, and two techniques for measuring enzyme action indirectly. An interesting aspect of studying enzymes is that it is usually not possible to directly observe them performing their functions - each enzyme is just too small. Because of this, biologists need to use indirect methods of observing enzyme action, by using techniques that make the enzymes' effects measurable somehow - often as a visible colour change. These techniques are often simple, but ingenious. In your experimental design, you will need to plan for the use of these techniques in order to produce measurable results. Another interesting aspect of studying enzymes is that their action can be studied in vitro - that is, in test tubes rather than within organisms.
Bon apetit!
Pancreatitis: Causes [Internet]. 2011. Mayo Foundation for Medical Education and Research; [updated 2011 Jan 15; cited 2012 Aug 24]. Available from: http://www.mayoclinic.com/health/pancreatitis/DS00371/DSECTION=causes
Ruthenbürger M, Mayerle J, Lerch MM. 2006. ell biology of pancreatic proteases. Endocrinology and Metabolism Clinics of North America. 35: 313-331.
Westermarck E, Wilberg M. 2012. Exocrine Pancreatic Insufficiency in the dog: historical background, diagnosis, and treatment. Topics in Companion Animal Medicine. In press.
This is the follow-up to the lab that you worked on a few weeks ago. For this part of the lab you will:
There is no additional online content for this lab; see the assignment document in the associated dropbox for full details.
By the end of the two labs related to this topic you should be able to...
1. Describe the role of enzymes in general and pancreatic enzymes in particular in animal digestion.
2. Discuss why disease models are useful for understanding normal systems, with specific reference to pancreatitis and pancreatic enzymes.
3. State a testable hypothesis and design a simple experiment to address it, distinguishing between hypothesis and prediction, direct and indirect observation, and controls and treatments.