Beacon Lesson Plan Library

Enzymatic Action

Jacqueline Roberts
Bay District Schools

Description

Enzymes are specialized proteins that regulate chemical activity in the body without themselves being altered in the reaction. In this lab, students observe how a cell uses an enzyme to rid itself of a poisonous substance.

Objectives

Selects and uses appropriate instruments, technology, and techniques to measure quantities in order to achieve specified degrees of accuracy in a problem situation.

Interprets data that has been collected, organized, and displayed in charts, tables, plots.

The student understands how knowledge of energy is fundamental to all the scientific disciplines (e.g., the energy required for biological processes in living organisms and the energy required for the building, erosion, and rebuilding of the Ear

The student understands that biological systems obey the same laws of conservation as physical systems.

Materials

Materials for each group participating in the lab:

-Clock with second hand or stopwatch
-Calculator (optional)
-Graduated cylinder - 25 ml.
-Hydrogen peroxide (3%) - 45 ml per group
-Stirring rod
-Potato (raw)
-Liver
-Carrot
-9 test tubes (If experiment is done on consecutive days or multiple days, 3 or 4 test tubes per day would suffice per group.)
-Funnel
-Test tube rack
-Thermometer
-Test tube clamp
-Colored Pencils
-1 small aluminum pie pan or glass evaporating dish
-Safety apron (one per student)
-Goggles (one per student)
-Resource Material: [Biology:Visualizing Life]. Holt, Rhinehart and Winston, Inc. Orlando, Florida 1998.
-Weblinks listed below

Preparations

1. PRE-LAB (Student Knowledge)
Understands the following vocabulary terms and their application to biological systems: chemical change, physical change, substrate, activation energy, protein, amino acid, enzyme, enzyme-catalyzed reaction, and catalyst.
Understands enzymes are catalysts and are essential to every biochemical reaction in the body.
Understands without enzymes biochemical reactions in living things would cease.
Understands most chemical reactions in living things involve the making or breaking of bonds, thus releasing energy in the form of heat.
Understands that because enzymes are not changed or become part of a -product-, enzymes comply with the Law of Conservation as it applies to biological systems.
Understands that energy can be observed in many forms, the most observable is heat.

2. PRE-LAB (Teacher)
Inventories materials and supplies prior to lab.
Assembles all materials previous to beginning of class period.
Cuts liver, potato and carrot into inch pieces prior to the beginning of lab. These items are placed in an evaporating dish or small pie pan.
Sets up Cooperative Learning Groups. Students are divided into groups of 3 -5 with leader, secretary, material retriever and material manager.
Multiple day experiment - distribute only the amount of hydrogen peroxide and food items you anticipate using that day.
Be aware that the result of a biochemical reaction between hydrogen peroxide and an enzyme will include the release of water and oxygen.

Procedures

PLEASE READ TEACHER PREPARATION BEFORE BEGINNING THIS LAB.
PRE- LAB (Whole Group)
CLASS DISCUSSION
a) Describe characteristics of chemical change.
b) Describe characteristics of physical change.
c) What is a catalyst? Give an example.
d) Why is an active enzyme an example of chemical change?
e) Describe various forms of energy.
f) As a result of biochemical reaction, energy will be given off in this experiment. What form(s) of energy could be anticipated in this laboratory experiment? What form would be the easiest to measure?
g) As a result of biochemical reaction, enzymes will produce a product(s). What do you think the product(s) will be?

SAFETY PROCEDURES
a) Safety goggles and laboratory aprons are worn through out the investigation.
b) Hydrogen peroxide is poisonous. First Aid/safety procedures are activated immediately if hydrogen peroxide comes in contact with the skin or is spilled in the lab.
c) Chemicals are transferred from one container to another, using a funnel.
d) Clean up at the conclusion of the lab is everyone's responsibility.

LAB TECHNIQUES
a) The bulb of the thermometer does not rest on the bottom of the test tube.
b) The stopwatch runs continuously.
c) The timekeeper gives a -4-3-2-1- Time- when requesting a temperature reading.
d) Temperature of hydrogen peroxide is measured BEFORE liver, potato or carrot is placed in the test tube.

PART A. Student Introduction:
1. Student (secretary) reads lab to group.
2. Student (materials manager) gathers all necessary supplies for the lab.
3. Student materials manager and leader) set-up lab according to directions as read by the secretary.
4. Student (secretary) prepares data sheet to record results (See Attachment) 5. Student group prepares a hypothesis.

PART B. Activity 1(LIVER):
(1). Student places masking tape on nine test tubes. (Remember if experiment is multiple day experiment, distribute only the amount of hydrogen peroxide and test tubes you anticipate using that day.)
(2). Student labels the test tubes 1 through 9.
(3). Student places 15 ml of hydrogen peroxide in a 25 ml. graduated cylinder.
(4). Student places 5 ml. of hydrogen peroxide in test tube 1 and 2 and 3.
(5) Student places a thermometer in test tube 1.
(6). After 30 seconds the temperature is recorded on data table 1 (see attachment Data Table 1).
(7). Student removes thermometer from the test tube.
(8). Student adds a small piece of liver to test tube.
(9). Student replaces thermometer and begins to record the temperature of the liver and hydrogen peroxide every 30 seconds for 5 minutes.
(10). At completion of data collection, student discusses observations with partners and record observations on Data Table 4.
(11). Student repeats activity (steps 5 through 10) in test tube number 2 and
3. (Remember to check the temperature of hydrogen peroxide before placing the liver in the test tube).
(12). Student totals and averages test tube temperatures on data sheet.
(13). Student plots average temperature gain or loss on graph. (See Data Sheet 5)




Activity 2 (POTATO):
(1). Student places 15ml. of hydrogen peroxide in a 25 ml. graduated cylinder.
(2). Student places 5 ml of hydrogen peroxide in test tube 4 and 5 and 6 .
(3). Student places a thermometer in test tube 4.
(4). After 30 seconds the temperature is recorded on Data Table 2 (See Attachment )
(5). Student removes thermometer from the test tube.
(6). Student adds a small piece of potato to test tube.
(7). Student replaces thermometer and begins to record the temperature of the potato and hydrogen peroxide every 30 seconds for 5 minutes on data sheet.
(8). At completion of data collection, student discusses observations with partners and record observations on Data Table 4. Student repeats activity (steps 2 through 8) in test tube number 5 and 6. (Remember to check the temperature of hydrogen peroxide before placing the potato in the test tube.)
(9). Student totals and averages test tube temperatures on Data Table 2.
(10). Student plots average temperature gain or loss on graph. (See Data Sheet 5)

Activity 3 (CARROT):
(1). Student places 15ml. of hydrogen peroxide in a 25 ml. graduated cylinder.
(2). Student places 5 ml of hydrogen peroxide in test tube 7, 8 and 9.
(3). Student places a thermometer in test tube 7.
(4). After 30 seconds the temperature is recorded on Data Table 3 (See Attachment).
(5). Student removes thermometer from test tube.
(6). Student adds a small piece of carrot to test tube.
(7). Student replaces thermometer and begins to record the temperature of the carrot and hydrogen peroxide every 30 seconds for 5 minutes on Data Table 3.
(8). Student repeats activity in test tube number 8 and 9. (Remember to check the temperature of hydrogen peroxide before placing the carrot in the test tube.)
(9). Student discusses observations with partners and record observations on Data Table 4.
(10). Student totals and averages test tube temperatures on Data Table 3.
(11). Student plots average temperature gain or loss on graph. (See Data Sheet 5)

Assessments

Students are assessed on their participation and their written lab work. There is a rubric in the associated file to use. Students who do not understand the concept of energy and biological processes or who are not able to correctly graph their data need additional instruction and feedback from the teacher.

Web Links

Web supplement for Enzymatic Action
Enzymes

Web supplement for Enzymatic Action
Enzymes

Attached Files

1. Data Sheets 1 through 5 2. Lab Rubric 3. Written Assessment     File Extension: pdf

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