Biology 12

Unit 1 Investigation • MHR 99

Avoid contact between AgNO 3 and your skin

or clothing because AgNO 3 will cause stains.

If you accidentally spill chemical solutions on

your skin, immediately wash the affected area

with copious amounts of cool water. Inform

your teacher.

Wash your hands thoroughly with soap after

the lab.

Experimental Plan

1.Design a checklist or rubric that assesses the

completeness of the lab design and the lab

report. Compare your checklist or rubric with

those of two other groups. Submit a copy of

your checklist or rubric to your teacher.

2.Identify an enzyme reaction that you can

study. What are the names of the enzyme,

the substrate(s), and the product(s)?

3.List some factors that affect enzyme reactions.

Identify those factors that can be varied to

study changes in the rate of the reaction.

Support your thinking by calling upon your

understanding of the way enzymes work.

4.Design an experimental procedure to test

your hypothesis. Identify the control, and

the dependent and independent variables.

The steps must clearly explain how the

experiment will be carried out. Where

appropriate, use diagrams for clarity.

Explain how you will measure the rate of

the reaction. Identify the chemical you are

testing to measure the reaction rate.

Checking the Plan

1.Develop a flowchart relating the procedure

to the hypothesis. Include lists of materials.

Explain the purpose of listed chemicals.

Identify safety precautions required. Prepare

a data chart.

2.Share your plan with one or two other

groups for feedback. Revise your plan and

submit it to your teacher for approval.

3.Collect the materials you need.

4.Determine a benchmark reaction rate as a

control. Compare other reactions to this rate.

Data and Observations

1.Set up and perform the experiment. If

necessary, modify the experimental design.

Check the new design with your teacher.

2.Record data and observations. Present your

data in an effective format that is easy to

interpret and understand.

Analysis and Conclusions

1.Prepare a poster report of your work.

Include all of the report elements you

identified in your checklist.

2.Prepare an abstract, a brief summary of

the experiment and findings.

Assess Your Experimental Design

3.Use the checklist or rubric you developed

to assess your experimental design.

4.Compare your data with those of other

groups. How might you account for any

discrepancies? List ways you might improve

your experimental design and explain any

modifications you think would enhance it.

substrates product

enzyme–substrate complex

active site

enzyme enzyme unchanged

Substrates are brought close together in the active sites
of an enzyme, which lowers the activation energy of the
reaction by facilitating the bonding of the substrates to
form a product. After the substrates have reacted, the
product is released. The enzyme is then able to bind

more substrate molecules and continue catalyzing the

reaction. Substrates with shapes that do not match the

shape of the active site will not undergo the catalyzed

reaction, just as a house key cannot be used to start

a car.