What is the outcome of heating proteins?

Heating proteins causes them to undergo a process known as denaturation. This process involves breaking the weak bonds and interactions that maintain the protein's three-dimensional shape, such as hydrogen bonds, ionic bonds, and Van der Waals forces. As these bonds break, the protein loses its original structure and unfolds, which can change its function and properties.

The correct answer articulates that heating leads to a change in the protein's shape due to these broken bonds, which is a fundamental aspect of how proteins respond to temperature changes. This change is significant because it can affect the protein's biological activity, potentially rendering it inactive or altering the way it interacts with other molecules.

In contrast, other outcomes such as an increase in molecular weight, maintaining the original structure, or becoming more complex do not accurately describe the effect of heating on proteins. Heating does not increase the molecular weight of proteins but can instead lead to loss of functionality due to structural alteration.