Reactions that build larger molecules in the cell are called ; reactions that break down molecules into smaller ones are called .

Anabolic Reactions and Catabolic Reactions  

Explanation:

Anabolic Reactions -

Anabolic reactions are reactions that build larger molecules from smaller ones while the catabolic reactions are the reactions that break down molecules into smaller ones.  Anabolic reactions are also called biosynthetic reactions because they synthesize larger molecules from smaller molecules or constituent parts. The energy used by these reactions to proceed is ATP. Anabolic reactions occur in cells for the synthesis of new proteins and other reactions.

Catabolic Reactions -

Catabolic reactions are the reaction that includes the whole pathway of reaction that breaks down larger molecules into smaller units. These molecules are oxidized to release energy or sometimes used in other anabolic reactions occurring in the cell.