TABLE OF CONTENTS The laboratories, lectures, and appendices in this section emphasize the critical nature of proper pipeting. They provide practice in preparing nucleotide and amino acid samples and then characterizing them using ultraviolet absorbance spectrophotometry. Pipeting errors are characterized and the concept of propagated error is explained and illustrated. Protein concentration is measured next, illustrating a simple assay of the total peptide group concentration using a coupled redox-activated dye technique, the BCA assay. All enzyme activity assays (see section 2) require determining protein concentrations, so accomplishing the key goal of monitoring improvements in protein activities requires multiple applications of this fundamental measurement.
A majority of the scientific activities done to date under the heading "molecular biology" have involved studying (1) production of proteins, (2) functions catalyzed by them, or (3) controls mediated by them. Most typical projects proceed by the fundamental steps: (1) the gene that encodes the protein is captured in an expression plasmid, (2) the DNA sequences are determined, and (3) the protein is produced via transcription and translation by a virus, bacterium, yeast, or higher eukaryotic cell. Thus, we will focus on the pathway of processes that lead from the DNA to its RNA transcript to the translated protein, with emphasis on how biomolecular structures and the conditions of the surrounding medium work together to produce functionality.
The laboratories and lectures in this section are intended to teach the points to consider in the course of this type of research. Doing reliable experiments is necessary...
