Enzyme Activity (Chemical Processes of Digestion, Ex 39A)

Transcription

1 Enzyme Activity (Chemical Processes of Digestion, Ex 39A) Bio 2402 Ziser, 2004 Human Physiology at its most basic level is biochemistry. For every physiological activity that our body performs; individual cells are carrying out dozens or hundreds of specific chemical reactions required for that activity. Almost all of the chemical activity that is occurring inside our body cells involves enzymes. Enzymes are the biological catalysts that allow these reactions to occur. Enzymes are required for both anabolic and catabolic reactions. These reactions usually occur in sequenced sets called metabolic pathways. In this exercise we will investigate some of the simplest and best known of these enzyme reactions, those involved in the chemical digestion of food. We will study some of the simple enzymes that decompose large organic molecules into their component parts. Read the introductory material beginning on page 405 before you come to lab. Activity: Developing Hypotheses for Experiments on Enzymatic Digestion Work together as a group to develop one or more hypotheses for each of the enzyme experiments and record them on your data sheets At the same time determine which of the tubes are serving as controls and what exactly they are controlling for. Record this information on your data sheet. Activity: Assessing Starch Digestion by Salivary Amylase changes: add three ml (not drops) of to each test tube you will collect your own salivary by collecting saliva in a small beaker, dilute your saliva 50/50 with distilled you will need 1 ml of the saliva mixture for each tube. Those who donate the saliva should not have just eaten food or drink in the past hour or so; collect your saliva in a 10ml graduated cylinder and then add an equal amount of DI to dilute it. b. Incubate at the appropriate temperature for 1 hr, shaking tubes intermittently using the vortex mixer c. Perform indicator tests as described d. use a spot plate for the tests Activity: Assessing Protein Digestion by Trypsin changes: add three ml (not drops) of each solution to each test tube b. Incubate at the appropriate temperature for 1 hr, shaking tubes intermittently by placing on vortex mixer c. Record changes as described Activity: Assessing Fat Digestion by Lipase skip Demonstrating Emulsification changes: to L and B tubes add 3ml of each liquid reagent to each tube as directed b. Incubate for 1 hr, shaking tubes intermittently using the vortex mixer c. Perform indicator tests as described skip: physical processes Cleanup and Disposal When you have completed all experiments: dispose of chemical wastes in the sink dispose of empty test tubes in the glass containers dispose of plastic droppers in trash clean beakers and other glassware with soap and, blot dry and return to your tray turn off the hot plate and vortex mixer before leaving

2 Name: Group: Due Date: Enzyme Activity (Chemical Processes of Digestion, Ex 39A) Bio 2402 Lab Data Sheet Activity: Assessing Starch Digestion by Salivary Amylase Tube Number Additives Amylase Digestion of Starch 1A 2A 3A 4A 5A 6A maltose Incubation Conditions 37º 37º 37º IKI Test (+/-) Benedicts Test (+/-) 4 min,100º then 37º 0º Which tubes are the controls? Why are there more than one control, what are each controlling for? Activity: Assessing Protein Digestion by Trypsin Tube Number Additives Trypsin Digestion of Protein 1T 2T 3T 4T 5T Incubation Conditions 37º 37º Color Change (+/-) 4 min,100º then 37º 0º

3 Which tubes are the controls? Why are there more than one control, what are each controlling for? Activity: Assessing Fat Digestion by Lipase tube number additives Lipase Digestion of Fats 1L 2L 3L 4L 5L 4B 5B incubation conditions 37º 37º color change(+/-) 4 min, 100º then bile salts bile salts 37º 0º 37º 0º Which tubes are the controls? Why are there more than one control, what are each controlling for?

4 General Questions: 1. Digestive enzymes are classified as hydrolases, what does this mean? 2. Name the final end products of digestion for each of the following organic polymers: Carbohydrates Proteins Lipids Nucleic Acids 3. a. What are your conclusions concerning your experiments with? 4. a. What are your conclusions concerning your experiments with? 3. a. What are your conclusions concerning your experiments with?

5 c. What effects did the bile have on activity?