Provide hands-on activities for practice and mastery. Check for understanding of concepts and skills by using relevant standard materials, i.e. worksheets, text problems, workbooks, teacher prepared exercises, etc.

Practice sheets consisting of experimental situations.

Objective: To have the students practice their understanding of enzymes through paper problem analysis and actual lab experimentation.

Activity: Students work on practice sheets which consist of varied experimental situations involving the use of enzymes. They get together in small groups to discuss and compare answers. At this point, it is also good for the students to actually try some experimentation which indirectly shows that action of an enzyme on a substrate. Many books use the example of sucrase acting on sucrose to facilitate its breakdown into glucose and fructose. Yeast cells make sucrase. A few grains or a small piece of yeast can stand in a cup of water for about twenty min. Then it should be filtered and the filtrate kept. The filtrate has the enzyme sucrase. To check for the presence of sucrase, the students fill two test tubes 1/4 full of sugar solution. Test one with Benedict's solution for the presence of glucose. Put out 6ml of the enzyme extract in the second tube. Let it set for an hour and test it with Benedict's; it will be positive showing sucrose was changed to glucose and fructose. The students can write a formal lab or do a flow chart of what took place or draw it in terms of a metaphor like the puzzle pieces.

Assessment: Quality of student work on problem situation sheets and lab activity.