8/10/2019 Bio 101 Sample Lab Report

1/3

Sample Lab Report

Title: The Effects of Temperature and pH on the Activity of the Enzyme Catalase

William Capitano !S!

Abstract

Enzymes are protein catalysts that speed up chemical reaction in living organisms. This

investigation tested the effects of temperature and pH has on enzyme activity. Catalase found in

potatoes was treated with different temperature (0o, 2o, !oand "00oC# and pH (2, !, and "2#.

$ata was collected %y measuring the amount of o&ygen produced. The results show that catalase

does not wor' at e&treme temperatures and pH levels. esults also suggest that high

temperatures and low pH denature proteins.

"ntroduction

Cells re)uire the use of enzymes to carry on life functions. These functions include %rea'ing

down molecules for energy, %uilding structural molecules such proteins and producing various

chemical messengers. *ecause most reactions re)uire high amounts of energy, they could not

occur in a cell without the aid of a catalyst. Enzymes are protein catalysts that %ind to molecules

allowing them to react faster. This can occur without the high amount of energy the molecules

would normally need.

Enzymes wor' %y the loc' and 'ey theory (+udesir' et al, 200, page -0# which states that

enzymes have a particular location, called an active site, where molecules (called su%strate# %ind.

*ecause of the shape of the active site only specific molecules can enter. +ny change to the

shape of the enzyme can affect its a%ility to %ind to the su%strate.

The purpose of this e&periment is to measure the effects of temperature and pH on enzyme

function. The enzyme we used is catalase which is a common enzyme found in many organisms.

Catalase %rea's down hydrogen pero&ide producing o&ygen and water.

aterials and ethods

or this e&periment we followed the protocols set out in /rinciples of *iology a%oratory

1anual (CCC, 200-. page 334!0#

Effects of temperature on enzyme activity

our "0 m test tu%es containing hydrogen pero&ide were incu%ated at different temperatures5

0oC, 2oC (two test tu%es#, !oC for five minutes. + small piece of potato was added to the four

test tu%es. The test tu%es were cor'ed with a 62 one4hole ru%%er stopper then inverted in their

water %aths for "0 minutes. 7as collected at the top (%ottom# of the test tu%es forcing pero&ide

8/10/2019 Bio 101 Sample Lab Report

2/3

out of the hole. The length of gas produced %y the reaction was measure in millimeters using a

metric ruler.

Effects of pH on enzyme activity

/ieces of potato were added to three test tu%es. The potato was treated to different pH levels58a9H (pH :"2#, dH29 (pH :!# and HCl (pH:2# for five minutes. The pH of each solution was

determined with litmus paper. The test tu%es were then filled with hydrogen pero&ide, stoppered

and inverted for "0 minutes at 2oC. The gas collected was measured in millimeters using a

metric ruler.

$ata from other groups in *io "0" la% was collected and averaged.

Results

The potato in the 0o, 2o, !oall produced o&ygen !oproducing the most (Ta%le "#. *oiled

potato produced no gas. 9ur data was close to the class averages (Ta%le 2# with the e&ception of!oC. The groups with the different pH treatments (Ta%le # were very similar to the class

averages (Ta%le ;#. HCl had the least amount of 92produced.

Table # easurements of $%produced at different temperatures

Temperature (oC# ength of 7as Collected (mm#

0

2 ect would not %e possi%le without the support of uffol' Community College,

/rofessional +ssistant *ar%ara ?oung, and the students of *io "0".

References

+udesir', T., +udesir', 7., *yers, *.E., 200. ife on Earth -thEdition. /earson *en>amin

Cummings. an rancisco, C+.

uffol' County Community College. 200-. /rinciples of *iology a%oratory 1anual. 1ac7raw

Hill /u%lishing *oston, 1+