Essential Idea
Enzymes control the metabolism of the cell.
Understandings
Enzymes have an active site to which specific substrates bind.
Enzyme catalysis involves molecular motion and the collision of substrates with the active site.
Temperature, pH and substrate concentration affect the rate of activity of enzymes.
Enzymes can be denatured.
Immobilized enzymes are widely used in industry.
Applications
Methods of production of lactose-free milk and its advantages.
Skills
Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes (VIDEO) (Virtual Lab - Pearson).
Experimental investigation of a factor affecting enzyme activity. (Practical 3)
Guidance
Lactase can be immobilized in alginate beads and experiments can then be carried out in which the lactose in milk is hydrolyzed.
Students should be able to sketch graphs to show the expected effects of temperature, pH and substrate concentration on the activity of enzymes. They should be able to explain the patterns or trends apparent in these graphs.
Key Vocabulary
Active site
Substrate
Catalysis
Rate of activity
Denature
Concentration
Textbook Reading and/or Activities
Click HERE for a pdf of chapter 2.
Notes
A detailed set of notes, prepared by Bob Smullen, examining all of the IB learning expectations.
Bioknowledgy Notes - A detailed set of notes, created by Chris Paine, examining all of the IB learning expectations.
Bioknowledgy Study Questions - A series of questions, created by Chris Paine, to help check your understanding of the IB learning expectations. This is VERY GOOD practice.
A detailed set of notes, prepared by Jacob Cedarbaum, examining all of the IB learning expectations.
2.5 Study Questions (NEW Syllabus)
A series of questions, prepared by Jacob Cedarbaum, to help check your understanding of the IB learning expectations. This is VERY GOOD practice but the OLD also includes some HL material so please mind the SL Understandings and Applications at left. Answers (OLD).
Learning Activities
Virtual Lab - Enzyme-Controlled Reactions
This virtual lab, prepared by McGraw-Hill, will help you better understand how changing the variables (pH and substrate concentration in this case) within an enzymatic reaction can influence enzyme activity. (Practical 3)
Lab - Factors Affecting Enzyme Activity
This lab activity satisfies Skill 2 (Practical 3) of the IB Bio. course.
Must Watch Videos
"How Enzymes Work" by Biology / Medicine Animations HD (1:18)
This video outlines the basic structure of an enzyme along with its active site and how this interacts with a substrate to form an enzyme/substrate complex.
"Enzymes and...Pac-Man" by Amoeba Sisters (4:05)
This video explains what enzymes are and how they function to speed up chemical reactions within living organisms.
This video outlines, in slightly more detail, the structure of an enzyme, it's active site, substrate binding, competitive inhibition and allosteric inhibition.
Should Watch Videos
"Enzyme Function" by University of Surrey (2:29)