Specialized protein molecules that control chemical reactions in the cell are

These are enzymes. These molecules allow for the cell to metabolize and break down other molecules within the cell. Enzymes are specialized for the exact substances that they are to work on, and are able to accelerate the reactions by acting as catalysts for these reactions.

Behavior

Explanation:

There are many ways by which individuals of the same species recognize mates to copulate. Individuals usually recognize other individuals of the same species by morphology. However, the recognition of individuals of the same species can be complex when there is great similarity between different species, as it happens, for example, in flies.  In these cases the recognition of specific behaviors can be essential. Behaviors can include movement, vocalizations, sounds etc.