2. Eat anything good lately? Do you know what happens to all that yummy food after it's swallowed?

5. Carbohydrate hydrolysis Basic storage molecule of carbohydrate is starch – amylase and amylopectin. Both can be hydrolyzed by the same enzyme – amylase In salivary gland – salivary amylase In small intestine – pancreatic amylase

6. Carbohydrate hydrolysis tests Iodine test for starch breakdown Add Lugol’s iodine (IKI) If starch present – purple color If starch absent – no reaction Benedict’s test for the presence of reducing sugars (glucose, maltose and fructose) Reduced sugars presence results in red precipitate Small amounts – result in green color

7. Protein hydrolysis Proteins – long chains of amino acids The enzyme pepsin secreted by the chief cells in the stomach, begins the process of protein digestion by breaking the proteins to shorter chains Most protein digestion occur in the small intestine with the help of pancreatic enzymes

8. Biuret’s solution contains NaOH and copper sulfate. In the presence of proteins the copper sulfate reacts with the peptide bonds and the mixture turn to deep violet color No proteins – no color Protein hydrolysis tests

9. Primary lipids in the diet are triglycerides. Very small and insignificant amount of lipids are digested in the mouth my lingual lipase and in the stomach by gastric lipase Fat digestion occur in the small intestine by water soluble enzymes. Bile from the liver serve as emulsifier by physically separation of lipids to small pieces. By that, it increases the surface area of the lipids and allow lipase to work Bile salts form aggregations of 20-40 molecules – micelles in which the hydrophobic units turn inside and hydrophilic to the outside The products of lipid hydrolysis are being dissolved into the micelles and being carried to the brush border of the small intestine Lipids hydrolysis

10. Lipids hydrolysis tests Some of the products of lipids hydrolysis are organic acids (fatty acids) These products decrease pH That provide a way to identify lipid digestion

11. Experiments - carbohydrates p. 613 B. Iodine test for starch breakdown: What is the purpose of this test? p. 614 C. Benedict’s test What is the purpose of this test?

12. Experiments - carbohydrates P 614 D. Experiment: Tube 1 – 10 drops of starch + 10 drops of water Tube 2 – 10 drops of starch + 10 drops of saliva Place tubes in 37 0 C for 30 min (why?) Take drop from each tube and add iodine. What do you expect will happen?

13. Experiments - proteins P 615 B. Biuret’s test What is the purpose of this test? C. Experiment Tube 1 – 10 drops of protein +10 drops of water pH 8 (why?) Tube 2 - 10 drops of protein + 10 drops of pancreatin Place tubes in 37 0 C for 30 min What do you expect will happen?

14. Experiments - lipids p. 615 B. experiment Tube 1 – 2 ml cream, 2 ml water (pH 8), bile salts, 15 drops of litmus solution (or use litmus paper) Tube 2 - 2 ml cream, 2 ml pancreatin (pH 8), bile salts, 15 drops of litmus solution (or use litmus paper) Tube 3 - 2 ml cream, 2 pancreatin, 15 drops of litmus solution (or use litmus paper) Place tubes in 37 0 C for 30 min What do you expect will happen?

15. Lab report Introduction – explain shortly the chemical digestive processes and where do they occur. State the objectives of the experiments Materials and methods – describe exactly how did you performed the experiments – include list of solutions and equipment and than describe the procedure Results – give detailed results for each experiment (use tables to show results) Discussion – explain your results and explain how does these experiment demonstrate the chemical digestion processes