The effects of cold
temperatures on enzymes
HBS 2
3/5/2012
Damian Florez
Damian Florez
HBS
March, 5
Formal Lab Report
Abstract
The experiment was performed to see the effects of cold temperature on amylase
production in the human body. It is important to humans because it shows how the body reacts in
conditions where extreme temperature is involved. Three test tubes were filled with equal amounts of
amylase, starch, and water. The test tubes were then placed in three different environments 0 degrees,
5 degrees, and 21 degrees Celsius. The test tubes were then tested for glucose production. The test tube
at 0 degrees showed the least glucose production. The Test tube at 5 degrees showed some glucose
production. The test tube at 21 degrees showed the most glucose production. Glucose was produced
more efficiently at a room temperature environment, compared to colder environments.
Background
The purpose of the experiment is to discover the effect of cold temperatures on digestive
enzymes. Homeostasis regulates body temperature to keep the body at around 37 Celsius. This
temperature is ideal for bodily functions, and as body temperature increases, so will metabolism. Low
body temperature or becoming dehydrated decreases the number of calories burned. The body
maintains 37 degrees for normal body functions, in a cold room a human will normally shiver to try to
maintain this temperature. The constant contractions and relaxation of the muscles will create heat.
If the body is cold it will not metabolize and will not produce glucose, which is an important
resource for the body. Without this, simple bodily functions may not get the needed energy and may
begin to fail.
If the body is unable to maintain a normal temperature (about 37 C) it will enter either
hyperthermia or hypothermia. Hyperthermia is when the body temperature increases beyond the
normal range, hyperthermia can kill you within hours if a high temperature is maintained. Hypothermia
is the opposite of hyperthermia and occurs when the body temperature is lower than the normal range.
Prolonged exposure to high or low temperature can cause significant damage to the body.
Enzymes are substances that catalyze (speed up) chemical reactions. On the surface of the
enzyme there is a small area called the active site or catalytic to which substrates are able to bind. The
binding of the substrate to the enzyme will cause the flexible enzyme to form to fix the substrate, called
Damian Florez
HBS
March, 5
Formal Lab Report
induced fit. Enzymes are highly specific and only certain substrates will fit certain enzymes. Each
enzyme has a temperature at which it will function best. A higher temperature generally causes an
increase in enzyme activity. As temperature increases molecular activity generally increases, causing
more collisions. However, if the temperature increases too much, the heat will denature the enzyme.
Cold temperatures on the other hand, slow down enzyme activity by decreasing molecule collisions.
(http://student.ccbcmd.edu/~gkaiser/biotutorials/proteins/enzyme.html)
Hypothesis
What is the effect of cold temperatures on digestive enzymes?
If you decrease the temperature of a starch and amylase (enzyme) solution, enzyme activity
should decrease due to less molecular collisions, resulting in less glucose.
Independent variable: Temperature
Dependent variable: Glucose levels
Materials and Methods
Equipment:

Amylase enzyme, 10% solution in water

Glucose test strips

Glucose solution

Distilled water

Beaker (3)

Ice

Test tubes (3)

Test tube rack

Thermometer

Starch

Safety glasses
Damian Florez
HBS
March, 5
Formal Lab Report
 Stirring rod

Droppers
Safety Concerns

Do not use broken or dirty glass

Clean up any spills or broken items immediately
Procedure
1. Collect your materials and place three test tubes (empty) inside the test tube
rack.
2. Prepare two beakers. One should have a little ice (allow it to melt), and the third
should have half ice/half water.
3. Place 2 ml of starch and 1 mL of amylase in 3 test tubes.
4. Let each beaker sit for five minutes then measure the temperature in Celsius.
Record it in a data table (see an example below).
5. Let one tube sit at room temperature. Place the two other test tubes in each
beaker and allow them to sit for ten minutes.
6. After the ten minutes, take the starch and amylase test tubes and dip one
glucose strip per test tube.
7. Allow the glucose strips to dry and indicate glucose levels ( about 5 minutes)
8. Record the amount of glucose in mg/dL (milligrams per deciliter) in a data table
similar to the one below.
9. After measuring the glucose in mg/dL, add ten drops of Benedicts solution to
the tubes and place them in a hot water bath for about 5 minutes.
10. Record if a color change occurred. (Blue to orange)
Temperature
Room Temp
Melted Ice
Half Ice
Glucose mg/dL
Benedicts Color Change
Damian Florez
HBS
March, 5
Formal Lab Report
Results
Temperature
Glucose mg/dL
Benedicts Color Change
Room Temp
21 C
300 mg/dL
Yes. Dark orange.
Melted Ice
5C
1000 mg/dL
Yes. Light orange.
Half Ice
0C
300 mg/dL
No. Stayed blue.
The results of the experiment were tested with both, glucose strips and Benedict’s glucose
testing solution. The amount of glucose represented by the glucose strips for room temperature was
300 mg/dL. For 5 degrees C 1000 mg/dL was shown on the test strips. For 0 degrees C 300mg/dL was
measured. The benedicts color changed was also used along with the test strips. Benedict’s solution
measures glucose by turning orange in the presence of glucose. After the room temperature test, the
benedict’s solution turned dark orange indicating glucose. At 5 degrees C the Benedict’s solution turned
light yellow, indicating some glucose. At 0 degrees C the solution stayed blue, indicating no or little
glucose.
Discussion
The results of the experiment showed that cold temperature effects the production of glucose
with starch and amylase. The glucose test strips did not show the trend, however. They indicated the
most glucose at 5 degrees C and equal amounts of glucose at 0 degrees and room temperature, which is
why they were deemed inaccurate. The main trends were measured by the benedict’s solution. At room
temperature the Benedict’s solution turned dark orange which indicates a lot of glucose was produced
by the starch and amylase. After the reactions at 5 degrees C the solution turned light orange, which
indicated some glucose production. At 0 degrees C the Benedicts solution did not change, because of
the temperature the amylase could not react with the starch. The results show a clear trend, that
lowering temperature also lowers glucose production.
The main problem with the results can be seen with the glucose test strips. They did not show
any trends and the results were random, this shows that the test strips were generally inaccurate.
Another problem with the test may have been that the measurements for all the beakers were made
Damian Florez
HBS
March, 5
Formal Lab Report
with a pipette. Pipettes may not always be an accurate measuring tool. The way to improve would be to
use more accurate tools, which would decrease the factor for human error by a significant amount.
Another experiment testing wider ranges of temperature that uses more accurate indicators could be
used to find the best and worst environments for producing glucose. Experiments that test for other
factors like pH and concentration, which were done in different groups, would also further this
understanding of glucose production.
Conclusion
In a cold environment glucose was produced less efficiently than in a room temperature
environment.