Scientific Inquiry Students conduct an investigation. Students use an appropriate technique to gather data, counting and recording the number of drops exiting a column prior to a color change. Using evidence, students develop descriptions and explanations. They explain how the order of elution helps one to determine the relative size of molecules and the interactions between molecules and Sephadex resin. Students also form a logical argument about the cause of a color change inside of a dialysis tubing bag.
Substances react in characteristic ways with other substances.
In this activity, the characteristic reaction of iodine with starch is used to observe the process of smaller iodine molecules moving into the membrane. The physical properties of compounds reflect the nature of the interactions among their molecules. The size of molecules control their interaction with sephadex resin. Carbon atoms bond to form a variety of structures, including molecules that are essential to life. Proteins are one class of these biochemical molecules.