Menu of Sample Enzyme Labs...
Lab 1 - Protease
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Lab 2 - Catalase
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Lab 3 - Lipase
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Lab 4 - Catachol Oxidase
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Prelab Instructions:
Class work assignment:
In groups (2-3 students) carefully read your assigned lab and answer the given questions. Then, identify (1) the general and focused research questions, (2) independent and dependent variables (include units for each, range for IV and sufficiency, i,e, replicates, for DV), (3) other variables which should be controlled (and how they could interfere and how to control them). Generate (4) a complete list of materials that would be needed, as well as (5) an outline of the steps necessary to carry out the procedure (a flow chart is very acceptable for this).
One document per group is fine, but be conscious of including all members of your group.
Class work assignment:
In groups (2-3 students) carefully read your assigned lab and answer the given questions. Then, identify (1) the general and focused research questions, (2) independent and dependent variables (include units for each, range for IV and sufficiency, i,e, replicates, for DV), (3) other variables which should be controlled (and how they could interfere and how to control them). Generate (4) a complete list of materials that would be needed, as well as (5) an outline of the steps necessary to carry out the procedure (a flow chart is very acceptable for this).
One document per group is fine, but be conscious of including all members of your group.
Individual Design Lab
After your group has done the prelab assignment on one of the labs above, follow-up with an individual assignment where you write a full design for a VARIATION on one of the four labs. At this point, you may find it helpful to consult with a partner and/or the teacher, but the lab design should be different from that of others. Everyone will get their own individual grades, according to the rubric shown below. This assignment will be graded and one (maybe two related) lab(s) will be chosen for the class to perform as a whole next week.
Make certain to include (but use the rubric below as the ultimate guide!)
clear identification of the IV, w/ range
DV, with uncertainty (precision) of the measurement tool
table of the variables to be controlled, their effects and how to control
scientific background
technique for acquiring sufficient replicates of DV
technique (and logic) for encompassing a meaningful range of iV
clear step-by-step directions (with citations!!)
safety considerations
plans for doing statistical analysis
Make certain to include (but use the rubric below as the ultimate guide!)
clear identification of the IV, w/ range
DV, with uncertainty (precision) of the measurement tool
table of the variables to be controlled, their effects and how to control
scientific background
technique for acquiring sufficient replicates of DV
technique (and logic) for encompassing a meaningful range of iV
clear step-by-step directions (with citations!!)
safety considerations
plans for doing statistical analysis
2013-2014 Data collection/analysis &conclusion/evaluation lab
To prepare solutions:
Gelatin (substrate) (as a class) -
Distribute into 9 (or 10) 200 ml beakers, one per group.
Bromelain Enzyme (from meat tenderizer) - Serial Dilutions
Gelatin (substrate) (as a class) -
- 2 pkgs (small -85 g) flavored gelatin --> 2 l beaker
- Add 450 ml boiling water
- Stir over low heat until dissolved
- Remove from heat, add 450 ml crushed ice
- Stir until melted
Distribute into 9 (or 10) 200 ml beakers, one per group.
- Pipette into sets of test tubes, 5 ml/tube
- Label with date and contents
- Should have sufficient for 2 sets of 6 tubes/group - for two sections
- Store refrigerated until use within 48-72 hours.
Bromelain Enzyme (from meat tenderizer) - Serial Dilutions
- As a class, follow procedure shown in diagram below.
- Each group should aliquot 2 mls of each dilution into capped and labelled vials.
- Store refrigerated until use within 24-36 hours.
- Calculate the concentration of the enzyme in g/ml for each level of the independent variable
- Identify the independent and dependent variables
- Formulate a research question and context (note form only)
- State hypothesis and sketch graph
- What initial data should be collected at the outset? (include instrumentation error)
- Incubate the substrate and enzymes under controlled conditions (note the appropriate temperature, times, volumes etc. used)
- Identify the necessary calculations (keep track of sig figs and appropriate decimal values)
- How to handle pooled data (available on shared doc - "Enzyme data Blocks 3&7")? (statistics)
- Some groups should try using spectrophotometer (see instructions below) to analyze the color intensity of the food coloring released by the enzyme activity.
- Research the specific chemical reaction catalyzed by bromelain and incorporate this into the conclusion section of the lab report.
- REPORT DUE: 2/3/14 (Include Data Collection and Processing and Conclusion and Evaluation Sections - see rubrics below)
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WHAT WAVELENGTH TO CHOOSE? FIND THE PEAK FOR THE RED FOOD COLORING SPECTRUM...500nm
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Ta-da!
Other alternative labs
From Fall 2012 - Lab #2 - Catalase. IV - source of enzyme extract [range: animal/beef liver (Bos taurus), plant/germinating bean seed (Phaseolus vulgaris), fungus/yeast (Sacchromyces cerivisiae)]
DV - production of oxygen gas (ml, measured in graduated cylinder with 1 ml increments)
Discuss scientific background/context with large group.
Materials: (in bins)
3% (w/v) Hydrogen Peroxide (convert to molarity - think molecular weights and definition of % as g/100ml)*
yeast (prepared as 7g/100 ml 2% glucose - also convert glucose concentration to molarity - similarly, 2% glucose is 2g/100 ml solution, find molecular weight and calculate as above.)*
bean seeds (soaked overnight to induce germination)* 10-20g homogenized in 100 ml*
beef liver (previously frozen) * 10-20g homogenized in 100 ml
mortar/pestle
water
bucket
100 ml graduated cylinder
10 ml syringe
plastic tubing (on syringe)
hose clamp
test tube (30 ml Corex type)
2-holed rubber stopper
glass bend with rubber tubing (to water)
10 ml grad cylinder
1 ml pipettes
at stations:
ring stand and two clamps.
*solution shared by whole class and/or groups at neighboring lab stations
timers/clock
Prepare diagram of apparatus similar to Lab#2 above, as discussed in class. Include notation as to where the (1) amount of enzyme used is regulated (2) amount of substrate provided is shown and (3) amount of product measured is located.
Also take class notes on the biochemistry of catalase, including proposed mechanism of the reaction, the variety of toxins metabolized by catalase, and two inhibitors of catalase reaction, one competitive, one, non-competitive. (Oh so useful for the conclusion/evaluation section of your report!)
Data collection and processing: you also have to do some data processing of the results.
initial volume, final volume, showing gas produced,
time elapsed,
amount of enzyme, substrate used,
rates of enzyme activity with the given amount of enzyme and substrate used,
differences in rates between different sources of enzymes.
yeast: 7 g/100 ml 2% glucose
liver: 10 g liver (previously frozen)
100 g ice = ______ g water = ______ ml water
50 ml liquid water
grind in blender 10 seconds
filter through 8 layers cheesecloth
store on ice until use
beans: passed on this part...
DV - production of oxygen gas (ml, measured in graduated cylinder with 1 ml increments)
Discuss scientific background/context with large group.
Materials: (in bins)
3% (w/v) Hydrogen Peroxide (convert to molarity - think molecular weights and definition of % as g/100ml)*
yeast (prepared as 7g/100 ml 2% glucose - also convert glucose concentration to molarity - similarly, 2% glucose is 2g/100 ml solution, find molecular weight and calculate as above.)*
bean seeds (soaked overnight to induce germination)* 10-20g homogenized in 100 ml*
beef liver (previously frozen) * 10-20g homogenized in 100 ml
mortar/pestle
water
bucket
100 ml graduated cylinder
10 ml syringe
plastic tubing (on syringe)
hose clamp
test tube (30 ml Corex type)
2-holed rubber stopper
glass bend with rubber tubing (to water)
10 ml grad cylinder
1 ml pipettes
at stations:
ring stand and two clamps.
*solution shared by whole class and/or groups at neighboring lab stations
timers/clock
Prepare diagram of apparatus similar to Lab#2 above, as discussed in class. Include notation as to where the (1) amount of enzyme used is regulated (2) amount of substrate provided is shown and (3) amount of product measured is located.
Also take class notes on the biochemistry of catalase, including proposed mechanism of the reaction, the variety of toxins metabolized by catalase, and two inhibitors of catalase reaction, one competitive, one, non-competitive. (Oh so useful for the conclusion/evaluation section of your report!)
Data collection and processing: you also have to do some data processing of the results.
initial volume, final volume, showing gas produced,
time elapsed,
amount of enzyme, substrate used,
rates of enzyme activity with the given amount of enzyme and substrate used,
differences in rates between different sources of enzymes.
yeast: 7 g/100 ml 2% glucose
liver: 10 g liver (previously frozen)
100 g ice = ______ g water = ______ ml water
50 ml liquid water
grind in blender 10 seconds
filter through 8 layers cheesecloth
store on ice until use
beans: passed on this part...
Bombardier Beetle - A creative use of catalase!
AP Lab - Peroxidase/Guaiacol - managing a complex protocol
Peroxidase is an enzyme that breaks down peroxides, such as hydrogen peroxide, and is produced by most cells in their peroxisomes. Peroxide is a toxic byproduct of aerobic
metabolism. Various factors — abiotic and biotic — could have a major influence on the efficiency of this reaction.
To determine the rate of an enzymatic reaction, a change in the amount of at least one specific substrate or product is measured over time. In a decomposition reaction of peroxide by peroxidase (as noted in the above formula), the easiest molecule to measure is oxygen gas, a final product. This can be done by measuring the actual volume of oxygen gas released or by using an indicator. In this experiment an indicator for oxygen will be used. The compound guaiacol has a high affinity for oxygen, and in solution, it binds instantly with oxygen to form tetraguaiacol, which is brownish in color. The greater the amount of oxygen produced, the darker brown the solution will become.
metabolism. Various factors — abiotic and biotic — could have a major influence on the efficiency of this reaction.
To determine the rate of an enzymatic reaction, a change in the amount of at least one specific substrate or product is measured over time. In a decomposition reaction of peroxide by peroxidase (as noted in the above formula), the easiest molecule to measure is oxygen gas, a final product. This can be done by measuring the actual volume of oxygen gas released or by using an indicator. In this experiment an indicator for oxygen will be used. The compound guaiacol has a high affinity for oxygen, and in solution, it binds instantly with oxygen to form tetraguaiacol, which is brownish in color. The greater the amount of oxygen produced, the darker brown the solution will become.
