Reasearch Experiment Lab Report

The materials and methods used in this experiment are as written from the Laboratory Supplement of David L. Shultz. To properly prepare for the experiment, the materials needed were one stoppered shell vial or small Erlenmeyer flask for flies, seventy flesh flies (Sarcophaga bullata, ice-cold to anesthetize them), one wire test-tube rack (small mesh), a few paper towels to cut the flies on, one razor blade, one enamel pan, one thermometer, one grease pencil, one piece of plastic wrap, one large plastic beaker filled with crushed ice, seven large glass test tubes to hold reagents, homogenate, and centrifuged fractions, seven glass reaction tubes (small size, about three inches tall), and seven plastic pipettes (one milliliter and controls). When all

Fifteen milliliters was transferred to a clean tube marked H, for whole homogenate, and kept on ice at all times. The remaining fifteen milliliters of homogenate was transferred to a clean centrifuge tube and placed in a beaker of crushed ice. A balance was prepared by putting fifteen milliliters of distilled water into a new centrifuge tube and both tubes were then placed into the refrigerated centrifuge. It was then centrifuged at 5000 rpm for twenty minutes. When the centrifuge stops, the tube containing the homogenate was retrieved and held at the same angle. The supernatant was poured into a clean, rinsed with distilled water, twenty-five milliliter graduated cylinder without pouring out the pellet. The volume of the supernatant was restored to fifteen milliliters with the homogenizing medium, shaken well and transferred to the clean tube, marked S, and kept on ice. The volume of S was exactly the same as H. Ice-cold homogenizing medium was added to the pellet to make the final volume exactly equal to the original volume centrifuged, fifteen milliliters. The tube was stopped and shaken to suspend the