Exercise 8: Chemical and Physical Processes of Digestion Activity 4: Pre-lab Quiz Results ! You scored 100% by answering 4 out of 4 questions correctly. ¥ 1 !Which of the following is/are true of bile? ! You correctly answered: It works by a physical process. ! ¥ 2 !The substrate used in this simulation is ! You correctly answered: vegetable oil. ! ¥ 3 !When fatty acids are liberated by lipase, the pH ! You correctly answered: decreases. ! ¥ 4 !One of the products of the chemical digestion of lipids is ! You correctly answered: fatty acids. ! Experiment Results ! Predict Question! 1 Predict Question: Which tube do you think will have the highest lipase activity? Your answer: tube 3 (lipase, deionized water, bile salts, pH 9.0 buffer). Stop & Think Questions ¥ 1 !What does the pH measure?! You correctly answered: both lipase activity and fatty acid release. ! ¥ 2 !Why is it difÞcult to detect whether lipase is active in tube 5 (lipase, vegetable oil, bile salts, pH 2.0 buffer)? ! You correctly answered: The pH is already very low, so a decrease in pH might be difÞcult to detect. Post-lab Quiz Results You scored 100% by answering 4 out of 4 questions correctly. ¥ 1 !What is the product of lipase hydrolysis? ! You correctly answered: fatty acids. ! ¥ 2 !From your results, which pH is ideal for pancreatic lipase digestion? ! You correctly answered: pH 7.0. ! ¥ 3 !Which tube conÞrms that there is no lipase in bile salts or vegetable oil? ! You correctly answered: tube 4 (deionized water, vegetable oil, bile salts, pH 7.0 buffer). ! ¥ 4 !Where in the body does pancreatic lipase hydrolyze triglycerides? ! You correctly answered: small intestine. ! Review Sheet Results ¥ 1 !Explain why you can't fully test the lipase activity in tube 5 (lipase, vegetable oil, bile salts, pH 2.0 buffer). ! Your answer: ! Because the pH in test tube 5 is already very low, it's hard to measure pH changes and how the release of fatty acids would affect the solution. ! ¥ 2 !Which tube had the highest lipase activity? How well did the results compare with your prediction? Discuss possible reasons why it may or may not have matched. ! Your answer: I chose the wrong test tube in my prediction and according to the experimental results the lipase had the highest enzymatic activity when it was! closest to the pH in the intestines. Test tube 1 had the closest pH to that of the small intestine.By the experiment results Test tube 1 has pH 6.21 3 !Explain why pancreatic lipase would be active in both the mouth and the pancreas. Your answer: ! The pancreatic lipase enzyme has the highest enzymatic activity in environment with pH around 7.! The oral cavity has pH around 7 and the small intestine around 6-7.5 so the enzyme would work well in both the mouth and the pancreas. ! ¥ 4 !Describe the process of bile emulsiÞcation of lipids and how it improves lipase activity. Your answer: ! The fat globules are broken down from large fat droplets into smaller droplets by bile salts which acts as an emulsiÞer of lipids which is physical(mechanical) process happening in the small intestine.When pancreatic lipase acts on the lipid it breaks it down. This is why the bile improves the lipase enzymatic activity. !