Observation: The reaction of bacteria and animal enzymes
when their environment is salt concentrated.
Question: Which of the two amylase solutions, bacteria or animal, will be more tolerant to high concentrations of salt?
Hypothesis: The result of adding salt concentration to each animal and bacterial amylase will result in varying reactions.
Prediction: If we add salt concentration to the animal and bacteria, then one will be more tolerant than the other.
Experimental design:
Experimental group: Group that receives animal or bacterial amylase.
Blank & Control groups:
· Blank- Tube B, which will receive NaCl and water.
· Negative control- Tube B
· Positive control- Tubes with Amylase added
Independent variable: Animal and bacterial amylase.
Dependent variable: Salt concentration.
Equipment and solutions needed:
-15 test tubes
-Salt concentration (2% NaCl concentrate)
-Deionized water
-Amylase solutions (stored at 4 degrees celsius); both bacteria and animal
-10 mL glass pipette
-Pair of cuvettes
-DNS reagent
-Micropipettes*with appropriate tips
-Spectrophotometer
-Rack for tubes
-Stopwatch
Experimental procedure:
- Fill glass beaker about ½ to ⅔ full with water, turn on hot plate so that boiling water will be ready
- Obtain and wash 15 test tubes
- Label the tubes as follows:
- Tubes A: Blank (0%, 0.5%, 1%, 1.5%, 2%)
- Tubes B: Animal (0%, 0.5%, 1%, 1.5%, 2%)
- Tubes C: Bacteria (0%, 0.5%, 1%, 1.5%, 2%)
- Add salt concentrations to all tubes (amount?)
- Add 100 uL of amylase(animal) to appropriate tubes(B); add 100 uL of amylase (bacterial) to appropriate tubes(C); do NOT add amylase to blank group(A)
- Agitate groups B and C tubes to ensure amylase and solution are well mixed
- Place all tubes orderly on the rack for *5 minutes to allow amylase to catalyze hydrolysis of NaCl(salt)
- Add 1000 uL of DNS to stop enzymatic reaction (NACl hydrolysis)
- Calibrate spectrometer by using tube A
- Measure the absorbance of tubes B and C at 540 nm, and record the data
Table and formulas needed:
Table-Curved line graph
Formulas-
C1V1=C2V2
NaCl Concentrations: 0%, 0.5%, 1%, 1.5%, 2% (might be wrong)
C1=2%
V1=0 uL
C2=0%
V2=450 uL
uL of water needed: 450 uL
C1=2%
V1=112.5uL
C2=.5%
V2=450 uL
uL of water needed: 337.5
C1=2%
V1=225 uL
C2=1%
V2=450 uL
uL of water needed: 225 uL
C1=2%
V1=337.5
C2=1.5%
V2=450 uL
uL of water needed: 112.5
C1=2%
V1=450 uL
C2=2%
V2=450 uL
uL of water needed: 0uL
- Line graph with different sets of data according to the enzymes and their environment (NaCl solution or water)