A laboratory exercise that uses colormetric assay and corn seedling shoots to study the induction of enzyme activity by a substrate.

A lab for students to develop skills in molecular biology techniques, scientific method while researching the enzymatic properties of the model enzyme, isocitrate dehydrogenase

Students are asked to develop a procedure for the determination of the amount of ascorbic acid in fresh and boiled cabbage tissue. In order to accurately determine the ascorbic acid content, students must take into consideration the following: a representative sample, aliquots, the boiling procedure, the presence of the enzyme ascorbic acid oxidase, and the release of ascorbate into the boiling water.

Honeybees provide a convenient source of insect flight muscle, a tissue especially rich in mitochondria. These organelles are easily isolated using simple laboratory equipment and their metabolic activity readily measured colorimetrically with the dye 2,6-dichloroindophenol, which changes from blue to colorless when reduced by the electrons produced during respiration. This system is well-suited for studying cell fractionation, experimental isolation of the major subcellular components responsible for glycolysis and the Krebs cycle, and the role of oxygen in respiration. It can also be used for simple enzymology experiments using the Krebs cycle enzyme succinic dehydrogenase.

Cells contain many specialized structures known as organelles which perform a variety of specific functions. To obtain precise information about the structure and functions of subcellular organelles, it is imperative to isolate them free from contaminating organelles. Marker enzymes are known to be localized exclusively in specific organelles and are used to monitor the separation of these organelles. In this exercise the homogenate of Dictyostelium discoideum will be fractionated by differential centrifugation to separate mitochondria, lysosomes, and contractile vacuoles. The fractions will be assayed for their marker enzymes: acid phosphatase for lysosomes, succinate dehydrogenase for mitochondria, and alkaline phosphodiesterase for the contractile vacuoles. This exercise presents two fundamental concepts to the students: organelle isolation and enzyme assays.

This simple assay makes use of the ability of the plant hormone GA3 to induce starch breakdown in the endosperm of a barley seed from which the embryo has been removed. The effect of the hormone is clear and repeatable. This exercise can be used in introductory biology courses to demonstrate a basic plant process, or can be modified and used to investigate more sophisticated questions in a developmental biology course.

This series of exercises is developed for students interested in health and natural sciences with little to no background in science and is meant to develop their reasoning skills.

These laboratory exercises should be used to teach the basic properties of enzyme activity, including the effects of temperature, enzyme concentrations, and substrate concentrations.

Equilibrium of biochemical reactions is seldom taught in introductory biology labs. However, equilibrium is an excellent topic for the introduction of simple mathematical modeling into the lab curriculum. When properly done, modeling can allow an exploratory, hands-on approach to equilibrium, as well as teach a valuable application of mathematics. Stella modeling software facilitates the exercise by allowing students to construct sound models without dwelling on mathematical details. This exercise illustrates a modeling approach to reaction equilibrium and some aspects of thermodynamics. We use this exercise in introductory biology laboratories at Clemson University.

This investigation introduces students to the structure and function of the proteolytic enzyme, bromelain, which is present in large quantities in the fruit, leaves, and stems of pineapple. In this lab exercise, students study the rate at which bromelain catalyzes the hydrolysis of gelatin (substrate) at different temperatures and pHs. Strips of developed black and white photographic film are placed in freshly squeezed pineapple juice under different experimental conditions. The time it takes for the film to clear is used as an indicator of the rate at which bromelain catalyzes the hydrolysis of the substrate (gelatin), which binds the black silver grains to the plastic backing of the film. This lab exercise has been used in traditional non-majors and mixed majors/non-majors General Biology labs and can easily be adapted to an investigative approach.