CHEMICAL ENERGY FOR LIFE
PROBLEM: HOW WILL TEMPERATURE CHANGE AND PH CHANGE AFFECT THE ACTIVITY OF
ANIMAL AND PLANT ENZYMES?
ENZYMES GREATLY SPEED UP THE RATE OF NEARLY EVERY CHEMICAL REACTION THAT
TAKES PLACE IN LIVING ORGANISMS. THE ENZYMES ARE NOT CONSUMED DURING THESE
REACTIONS AND ARE CONSIDERED TO BE ORGANIC CATALYSTS.
THE ENZYME CATALASE SPEEDS UP THE DECOMPOSITION OF HYDROGEN PEROXIDE.
YOU ARE FAMILIAR WITH HYDROGEN PEROXIDE AS A COMPOUND USED AS AN ANTISEPTIC. IT
CAN ALSO BE USED FOR BLEACHING.
PRE-LAB QUESTIONS
1-. WHY IS HYDROGEN PEROXIDE PRODUCED BY OUR CELLS?
2. WHAT DOES THE CATALASE
3.
ENZYME DO TO THE PEROXIDE?
WHAT DOES THE TERM CATALSYT MEAN? WHAT
IS
AN ENZYME? HOW DO THE TWO
TERMS RELATE TO EACH OTHER?
4. WHAT IS A CHEMICAL
5. WHAT DOES
REACTION? WHAT IS AN EXOTHERMIC CHEMICAL REACTION?
IT MEAN TO DENATURE AN ENZYME? WHAT WOULD YOU EXPECTTO HAPPEN
IN THIS LAB IF THE CATALASE ENZYME IS DENATURED?
HYPOTHESIS:
MATERIALS AND PROCEDURES
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HYDRDOGEN PEROXIDE
LIVER
POTATO
TESTTUBES
HOT WATER BATH
ICE WATER BATH
STIRRING ROD
pH INDICATOR
.
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o
1.
HCL SOLUTION
NaOH SOLUTION
THERMOMETER OR TERMPERATURE PROBE
STOP WATCH
POUR 2ML OF HYDROGEN PEROXIDE INTO A TESTTUBE. RECORD THE TEMPERATURE OF
THE PEROXIDE BEFORE ADDING LIVER IN THE TABLE FOR
2.
O
SECONDS.
i'3
ADD A PIECE OF LIVER AND RECORD THE TEMPERATURE EVERY
*
b*
SECONDS FOR#"SECONDS
IN THE TABLE PROVIDED
3.
NOW REPEAT STEPS 1 & 2 WITH A PIECE OF POTATO IN A SEPARATE TEST TUBE.
4.
DISCARD THE PEROXIDE FROM THE TUBES INTO THE SINK, BUT DO NOT POUR OUTTHE
LIVER OR POTATO.
5.
NOW TAKE A NEW TEST TUBE AND ADD 2ML OF FRESH PEROXIDE. RECORD THE STARTING
TEMPERATURE FOR O SECONDS IN THE SPOT FOR OLD LIVER. ADD THE OLD LIVER TO THE NEW
PEROXIDE AND RECORD THE TEMPERATURE EVERY€ SECONDS
FOR6
SECONDS IN THE TABLE.
#-+
r
6.
REPEAT STEP 5 WITH THE POTATO AND RECORD YOUR RESULTS IN THE TABLE.
7.
THROW THE LIVER AND POTATO MIXTURE INTO THE GARBAGE (NOT DOWN THE
DRATN),
THEN CLEAN OUT THE TEST TUBES"
8.
NOW TAKE A NEW TESTTUBE AND ADD 2ML OF PEROXIDE. RECORD THE STARTING
TEMPERAUTRE FOR
9.
O SECONDS IN THE SPOT FOR ICE
WATER BATH.
TAKE A SECOND TEST TUBE AND PLACE A PIECE OF LIVER INTO THAT TEST TUBE. PLACE
THAT TEST TUBE INTO AN ICE BATH AND RECORD THE TEMPERATURE OF THE ICf: BATH. LEAVE
THE TEST TUBE IN THE ICE BATH FOR 5 MINUTES
10. .REMOVE THE TESTTUBE FROM THE ICE BATH, NOW TAKE THE LIVER OUT OF THE TEST
TUBE (YOU MAY NEED TO USE A STIRRING ROD FOR THIS) AND PLACE THE PIECE OF LIVER INTO
THE TUBE WITH PEROXIDE. RECORD THE TEMPERATURE EVERYSSECONDS FOR @SECONDS.
t3 !*!
11.
REPEAT STEPS 9
& 10 USING A PIECE OF POTATO AND
RECORD YOUR RESULTS IN THE
TABLE.
12.
DISCARD THE LIVER AND POTATO AND CLEAN THE TEST TUBES.
13. TAKE A NEW
TEST TUBE AND PLACE 2ML OF PEROXIDE. RECORD THE TEMPERATURE OF
THE PEROX}DE FOR
O
SECONDS IN THE SPOT FOR HOT WATER.
v
14.
PLACE
A
PIECE OF LIVER INTO ANOTHER TESTTUBE AND PLACE INTO A HOT WATER BATH
FOR 5 MINUTES.
15. REMOVE THE
LIVER FROM THE TESTTUBE IN HOT WATER, AND PLACE INTO FRESH
PEROXIDE. RECORD THE TEMPERATURE EVERYS SECONDS FOR
S
PROVIDED.
L+
IL:
16.
REPEAT STEPS 14
17.
DISCARD THE LIVER AND POTATO AND CLEAN THE TEST TUBES.
SECONDS IN THE TABLE
& 15 WITH POTATO.
18. NOW TAKE PLACE 2ML OF FRESH
PEROXIDE INTO A CLEAN TEST TUBE. RECORD THE
TEMPERATURE FOR O SECONDS IN THE SPOT FOR LIVER IN HCL.
19. TAKE A
FRESH PIECE OF LIVER AND PLACE IN A SPOT PLATE. ADD A FEW ML OF HCLTO THE
LIVER AND LET lT SOAK FOR 5 MINUTES. BE SURE TO TAKE pH
20. TAKE THE
of
HCL.
LIVER FROM THE HCL AND DROP INTO THE FRESH PEROXIDE. RECORD THE
TERMPERATURE EVERY 5 SECONDS FOR 30 SECONDS IN THE TABLE.
21. REPEAT
STEPS 78-2A USING POTATO.
22. DISCARD
LIVER AND POTATO AND CLEAN THE TESTTUBES.
23. PLACE zML
OF FRESH PEROXIDE INTO A TESTTUBE AND RECORD THE TEMPERATURE FOR
O
SECONDS lN THE SPOT FOR LIVER lN NaOH.
24. TAKE A FRESH PIECE OF LIVER AND PLACE INTO A SPOT PLATE. ADD NaOH AND SOAK
5 MINUTES. BE SURE TO TAKE pH OF NaOH.
25. REMOVE LIVE{ FROM NaOH
FOR
AND PLACE INTO TEST TUBE WITH FRESH PEROXIDE. RECORD
TEMPERATURE CHANUI EVERY 5 SECONDS FOR 30 SECONDS IN THE TABLE.
ANALYSIS QUESTIONS
1.
DOES THE LIVER CONTATIN AN ENZYME? HOW DO YOU KNOW?
2.
DOES THE POTATO CONTAIN AN ENZYME? HOW DO YOU KNOW?
3.
MANGANESE DIOXIDE DOES NOT COME FROM A LIVING THING" BASED OFF THE CLASS
DEMO, IS MANGANESE DIOXIDE A CATALYST? IS IT AN ENZYME? EXPLAIN!
4.
WHAT EFFECT DOES TEMPERATURE HAVE ON THE CATALASE ENZYME IN THE LIVER AND
POTATO? EXPLAIN
5" WHAT EFFECT
DOES pH HAVE ON THE CATALASE ENZYME IN THE LIVER AND PoTATo?
EXPLAIN
6.
DOES CATALASE,
7.
COMPLETE THE FOLLOWING CHEMICAL REATION:
AN ENZYME IN LIVING TISSUE, CHANGE HYDROGEN PEROXIDE INTO
NONPOISONOUS MATERIAL? EXPLAIN
THzaz + cATALASE
8.
ENZYME+- +
+ CATALASE ENzyME
BASED OFF YOUR RESULTS, IS THE ENZYME CATALASE USED UP AFTER CONTACT WITH
PEROXIDE? EXPLAIN
9.
WHY WAS CHANGE IN TEMPERATURE MEASURED IN THIS LAB?
10. MAKE A LINE
GRAPH SHOWING THE CHANGE IN TERMPERATURE OVER 30 SECONDS FOR
EACH OF THE TESTS COMPLETED. YOU SHOULD HAVE TWO GRAPHS, ONE FOR LIVER AND THE
OTHER FOR POTATO.
DATATABLE
&
TIME
LIVER
(sEc)
PERXOIDE
POTATO
OLD
OLD
LIVER
POTATO
LIVER
POTATO
LIVER
POTATO
LIVER
POTATO
&
LIVER
POTATO
lcE
ICE
HOT
IN
IN HCL
IN
lN NaOH
BATH
BATH
HOT
WATER
WATER
HCL
PEROXIDE
0
5
10
15
20
25
30
NaOH