Proteins are the workhorses of cells. Learn how their functions are based on their three-dimensional structures, which emerge from a complex folding process.

An indentured servant's contract could be extended as punishment for breaking a law, such as running away, or in the case of female servants, becoming pregnant.

Cells generate energy from the controlled breakdown of food molecules. Learn more about the energy-generating processes of glycolysis, the citric acid cycle, and oxidative phosphorylation.

Exponential growth is a pattern of data that shows greater increases with passing time, creating the curve of an exponential function.