Bacteria Make Thrift a Habit (IMAGE) University of Michigan Caption Some proteins cost more (in terms of energy) for cells to produce than others. The bacterium Escherichia coli "spends" more on proteins that will be used and recycled internally than on proteins that are secreted from the cell and lost to the environment. Credit Daniel R. Smith Usage Restrictions Image may only be used with appropriate caption or credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.