SBI 4U

Panayiotou

FACTORS AFFECTING ENZYME ACTIVITY

INTRODUCTION

There are various factors that can affect enzyme activity. Depending on the enzyme, it can be very sensitive to one particular factor but not another. In this investigation, three enzymes will be investigated: catalase, lactase, and amylase. Your group will be examining one factor from the list below that might affect the activity of amylase or lactase.

Factors to be examined:

a.  temperature

b.  pH

c.  concentration of enzyme

d.  concentration of substrate

e.  other (your choice)

Examining lactase activity:

When lactase is placed in milk it will break down the lactose to glucose and galactose. The level of glucose can be measured using glucose test strips throughout the experiment.

Examining amylase activity:

Amylase brakes down amylose (starch) to maltose (sugar + sugar). Iodine is used to indicate the level of starch left and glucose test strips can be used to determine the level of glucose throughout the experiment.

SAFETY

Goggles MUST be worn when dealing with certain chemicals at all times!

INSTRUCTIONS

·  Make a hypothesis regarding your factor and how it will affect the two enzymes your larger group is investigating.

·  Design the investigation for your particular enzyme. Take into account the independent, dependent and controlled variables. Identify the types of observations to be made. Make a list of all the materials you will need.

·  Conduct the experiment. Record your data in organized tables. You might have to repeat your experiment.

·  Compare your results to others in the class.

·  Write your report.

EVALUATION

Marks
Purpose / 1
Hypothesis (for each enzyme) and reasoning behind hypothesis / 2
Materials / 2
Procedure
·  Procedure should be written in paragraph form using the past passive tense / 5
Observations
·  Data tables and graphs analyzing your results
·  remember graphs on graph paper or computer generated graphs are only acceptable
·  Graphs can be used to not only display the end results (how much product was made), but also the rates of enzyme activity. / 5
Analysis
·  In paragraph form, discuss the results obtained from your data. Include in your description:
·  The reaction that took place in each case
·  The optimum conditions for enzyme activity based on your results
·  Relate to where the reaction occurs in the body
·  How other factors may affect your enzyme’s activities
·  How your factor affects different enzymes
·  Discuss experimental design and suggests methods to improve it
·  Discuss the significance of your experiment (the “so what’s the point”) / 10

TOTAL VALUE: 25 MARKS