The Department of Biology at Grinnell College is in the process of revising its sophomore-level core course in Cell Biology. In the past the laboratory consisted of a series of independent exercises where important techniques were learned but the experience was not unified in any way. We propose development of a series of sequential experiments unified around the study of cellular structure and function, made possible by fractionation of organelles. Laboratories are planned to prepare organelles from plant and animal tissues for the study of the activities of selected organelles such as oxygen consumption by isolated mitochondria, electron flow in isolated chloroplasts, kinetic studies of marker enzymes for different cellular fractions, organization, and protein diversity in differentiated tissues. All equipment necessary for these laboratories is available with the exception of an ultracentrifuge and rotors. We also propose updated experiments in four upper-level courses where ultracentrifugation will be necessary for preparation of fractions for the study of plasma membrane function, plasmid isolation, purification of virus particles and examination of fractions by electron microscopy. The addition of an ultracentrifuge will make it possible for the department to broaden the firsthand experience of students with modern biological instrumentation.
