Physiology & Anatomy Lab SC 145L Anatomy & Physiology I Lab
Chemical and Physical Processes of Digestion
Introduction: In this lab, we will see how different chemical processes occur as we observe how different enzymes digest different substrates and produce subunits.
Key Terms: (found in bold in Lab Manual)
Please define all bold terms in your own words:
Enzymes- Large protein molecules made by your body cells.
Catalyst- Without becoming part of the substance it will change the rate of the chemical reaction.
Hydrolyses- A enzyme that catalyzed a chemical bond.
Substrate- It’s a substance that an enzyme acts upon.
Salivary glands- Produces Saliva for digestion.
Stomach glands- Helps body make pepsin so you can digest protein
Pancreas- Creates juices like hormones and insulin. The juices help digest food in small intestine.
Liver- Works with Pancreas and intestines to digest, absorb, and process food. Its main job is to filter the blood that comes from digestive system Secretes bile.
Small intestine- It makes enzymes so body can make protein and starches.
Pepsin- It’s a protein-digesting enzyme.
Lipase- Hydrolyzes fats and oils.
Salivary and Pancreatic Amylase- Enzymes found in the pancreatic juices and saliva.
Bile acids- made in the liver and are responsible for emulsifying fats
Activity 1 and Activity 2– Assessing Starch Digestion by Salivary Amylase:
In this exercise, we will watch how salivary amylase (enzyme) works on a substrate starch and produces the subunits maltose and glucose.
Data:
Please submit Data for Activity 1 and 2.
Please answer the following questions
1. What ph allowed the highest amylase activity and why? Please explain. Ph 7.0 because that’s when it was most active and had the highest amounts of positive results. Had ++ results.
2. What effect does boiling have on enzyme activity? Boiling causes the enzymes to denature due to the high temperature.
3. Would the amylase present in the mouth be active in the stomach? Please explain your answer. No because the ph level in the stomach is too low. The mouth has a higher ph level and the acids in the stomachs stomach cause the ph to lower deactivating the amylase.
4. Does amylase digest peptidase? No, amylase digests starches peptidase is digested by protease.
5. Did Amylase use cellulose as a substrate? No it didn’t
Activity 3-: Protein Digestion by Pepsin
-In this exercise, we will observe the chemical digestion of proteins
Please record and submit Data for Activity 3.
Please answer the following questions:
1. Would pepsin be active in your mouth? No, it has to be exposed to HCI to become active and HCI is not in mouth.
2. What locations in the body does pepsin have the greatest activity? Stomach
3. What are the substrate and the subunits used in this experiment? The substrate is pepsin and BAPNA is the subunit.
4. What would happen if you decreased the incubation temperature to 0 degrees Celsius? I at first thought it wouldn’t make a huge difference but now I believe it would. Temperature can affect the results a lot. The lower the temperature the slower the activity and as the temperature increase the activity would speed up. Therefore, if temperature were 0 degrees Celsius the activity would decrease. Below 0 degrees Celsius it would deactivate
5. What effect did boiling have on pepsin activity? Forms a mass like boiling an egg.
Summary: Please summarize your data and explain how temperature and ph affected protein digestion.
Activity 4: Assessing Fat digestion by Pancreatic Lipase and the Action of Bile
Please record and submit your data for activity 4.
Please answer the following questions:
1. At what ph, did lipase have the greatest activity? Test tube 3 with a ph of 9.0
2. Is the activity of bile a chemical or a physical process? Please explain. It is a physical process because the change didn’t change the substance itself.
3. What is the substrate in the experiment? What are the subunits? Vegetable oil is the subunit and lipase is the substrate.
4. What happens to enzyme activity if we boil the enzyme? It denatures and inactivates the enzymes. Enzymes increase activity with rising temperature until it gets to 60 degrees then it deactivates and denatures the enzymes.
Summary: Please summarize the data. Where did lipase have the greatest activity and please correlate this to temperature and ph.
Activity 5: Mechanisms of Food propulsion and Mixing: Deglutition (Swallowing)
Please answer the following questions: (No data needs to be submitted)
1. Explain the significance of the movement of the tongue during swallowing. It helps push the fluids to the back of the throat using a wavy rippling motion. I don’t think I could swallow fluids without it.
2. Describe three events that occur during the pharyngeal-esophageal phase of deglutition. Mouth, nasopharynx, and larynx are blocked; upper esophageal sphincter relaxes to open esophagus; food moves through esophagus by pressure gradients created by peristalsis
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