BIOL 109 Enzymes Assignment FULL Name HARSH .

Spring 2023
Student No. 100172304

INSTRUCTIONS – Please read these instructions carefully.

This is an individual assignment.

Use the graph paper provided on pp. 142-145, or you may use Excel to plot your graphs. Graphs drawn
free-hand will be given a grade of zero.

Complete this assignment and submit a SINGLE PDF file of the entire assignment (including this page)
into the submission portal on eLearn. If you submit more than one PDF file, only the first one will be
marked.

Your academic integrity pledge (next page) must be included in your single PDF file.

IF YOUR ACADEMIC INTEGRITY PLEDGE IS MISSING, YOUR ASSIGNMENT WILL NOT BE

MARKED.

You must attend the Enzymes Lab (Lab #5) – if you do not attend the lab, you will not receive a mark for
this assignment.

NO LATE ASSIGNMENTS OR HARD COPIES OF THE ASSIGNMENT WILL BE ACCEPTED.

 Academic Integrity Pledge

The Enzymes assignment is an individual assignment – that is, you are to complete this assignment completely
on your own. While you are permitted to work on the assignment together, you must submit the assignment in
your own words (that is, you cannot submit the exact same, word-for-word assignment as someone else in the
class)

Capilano University Policy on Cheating and Plagiarism:

Cheating and plagiarism includes but is not limited to:
i. Asking someone else (online or in person) to complete this enzymes assignment for you
ii. Submitting the same Enzymes assignment as another student in BIOL 109/110
iii. Submitting an enzyme assignment from a previous semester that another student has written
iv. Copying word for word from any source, including the internet, textbook, lecture slides and lab
slides

If you are caught cheating or plagiarizing, a report will be written by the instructor with
recommendations for a course of action and sent to the Dean of the appropriate Faculty and the Students
Rights and Responsibilities Officer.
For more information, please see:
https://www.capilanou.ca/media/capilanouca/about-capu/governance/policies-amp-procedures/senate-policies-
amp-procedures/S2017-05-Academic-Integrity-Policy.pdf

By signing this pledge, you agree that you:

 Are submitting your own, original work written in your own words (and not anyone else’s,
including a classmate, the textbook author, the lecture instructor or the lab instructor)

SIGN BELOW ON THE LINE TO INDICATE THAT YOU HAVE READ AND UNDERSTAND THE
ABOVE STATEMENTS REGARDING CHEATING AND PLAGIARISM

Harsh .
SIGNATURE

HARSH ._
FULL NAME

100172304
STUDENT NUMBER
Enzymes Assignment

Part 1 – Raw Data Graph (6 marks)

1. Prepare 1 raw data graph (hand drawn on graphing paper) from one of the following experiments.
a) Effects of temperature (Table 15)
b) Effects of pH (Table 17)
c) Effects of an inhibitor (hydroxylamine) (Table 19)

Answer (c)
ABSORBANCE AT 510nm
tubes 2 & tubes 4 & tubes 6 & tubes 8 &
time(sec) 3 5 7 9
0 0 0 0 0
20 45 63 58 66
40 32 45 40 53
60 18 34 28 36
80 10 24 19 26
100 7 17 13 19
120 4 12 9 14

70

60

50
Absorbance

40 tubes 2 & 3

30 tubes 4 & 5
tubes 6 & 7
20
tubes 8 & 9
10

0
0 20 40 60 80 100 120
time (sec)

2. Write one sentence that summarizes your graph.

Answer 2 -
The graph summarizes stating that Absorbance in the beginning and gradually decreases.
Part II – Derivative Plot (8 marks)

3. Prepare one derivative plot of your temperature data OR pH data and create a bell-shaped curve that shows
the optimum temperature or pH for peroxidase. Include a sample calculation to show how you determined your
data points on the graph. Write a one-sentence summary of the derivative plot. (See page 139 for Derivative
Graph information)

Derivative graph showing changes in the activity of peroxidase

at different pH using 510 nm

1.2

1
Enzyme activity

0.8

0.6

0.4

0.2

0
3 4 5 6 7 8 9
pH

4, Answer the following questions (Note: keep each answer to four sentences or less.)
a) Why does temperature affect the rate of an enzyme catalyzed reaction? (4 marks)

Answer (a) –

Temperature affects the rate of enzyme-catalyzed reactions by influencing the kinetic energy of molecules.
Higher temperatures increase molecular motion, leading to more frequent and energetic collisions between the
enzyme and substrate molecules. This enhances the formation of the enzyme-substrate complex and promotes
catalytic activity. However, extremely high temperatures can cause the enzyme to denature and lose its
functionality. Each enzyme has an optimal temperature range in which it exhibits maximum activity, as this is
when the enzyme's structure is most stable and its catalytic efficiency is highest.

b) Why does boiling the enzyme reduce the enzyme’s catalytic effectiveness? (2 marks)

Answer (b) –

Boiling an enzyme causes a significant reduction in its catalytic effectiveness due to the denaturation of the
enzyme's structure. The high temperature disrupts the non-covalent interactions that maintain the enzyme's
three-dimensional shape, including hydrogen bonds, disulfide bridges, and hydrophobic interactions. This
denaturation leads to a loss of the enzyme's active site's specific conformation, which is crucial for substrate
binding and catalysis. Without the proper structure, the enzyme cannot effectively interact with the substrate,
resulting in a decrease or complete loss of catalytic activity.
c) Why do changes in pH of the assay mixture cause the enzyme to be more or less effective? (3 marks)

Answer (c) –

Changes in pH of the assay mixture can alter the ionization state of amino acid residues within the enzyme's
active site. This affects the enzyme's ability to bind to the substrate and catalyze the reaction. Deviations from
the optimal pH can disrupt the enzyme's conformation, leading to a loss of its catalytic activity. Additionally,
extreme pH values can cause irreversible denaturation of the enzyme, rendering it completely ineffective

d) Why does a molecule like hydroxylamine alter the rate of the reaction? (2 marks)

Answer (d) –
A molecule like hydroxylamine can alter the rate of a reaction by acting as an enzyme inhibitor or substrate.
Hydroxylamine can interfere with the enzyme's active site by binding to it and blocking substrate access,
leading to competitive inhibition. Alternatively, hydroxylamine can chemically react with the enzyme or its
cofactors, modifying their structure or functionality and inhibiting enzyme activity. Additionally,
hydroxylamine may serve as a substrate itself, undergoing a reaction with the enzyme, which can affect the
overall rate of the reaction being catalyzed. The specific mechanism and impact of hydroxylamine on the
reaction rate depend on the enzyme and reaction involved.