We will present our general biology laboratory program in which students learn the process of scientific inquiry by planning and performing their own experiments. Hands-on experience is gained by turning familiar wetlab techniques, such as enzyme assays and yeast fermentation, into investigations rather than cookbook labs. Students also use a computer simulation, Fish Farm, to explore a complex, real-world problem. The purpose of this investigation is to provide students with experience assaying levels of pyruvate in common onion varieties and onion allies. An explanation of onion flavor chemistry is included.
Pyruvate concentration is estimated from a standard curve generated using known pyruvate standards.
A hand-held refractometer will provide an estimate of the soluble sugars present in the onion tissue. In this laboratory we will be using cellulose acetate electrophoresis to rapidly separate allozymes from tisue or whole organism homogenates. We will attempt to detect genetic differences between 3 natural populations of the same species at 10 different enzyme loci. We will enter this data into spreadsheets to calculate measures of gentic identity and genetic distance and attempt to establish the amount of gene flow and the relatedness of these populations. This laboratory investigates one form of genetic recombination in bacteria.