Here's why:

* Anabolic pathways build complex molecules from simpler ones, requiring energy input.

* Biosynthesis refers to the process of creating biological molecules, such as proteins, carbohydrates, lipids, and nucleic acids, from smaller building blocks.

Examples of anabolic pathways include:

* Protein synthesis: Amino acids are joined together to form proteins.

* Glycogenesis: Glucose is converted into glycogen for storage.

* Steroid hormone synthesis: Cholesterol is converted into various hormones.

* Nucleic acid synthesis: Nucleotides are joined to form DNA and RNA.

Key points to remember:

* Anabolic pathways are often coupled with catabolic pathways, which break down molecules and release energy.

* The energy released from catabolic reactions is often used to fuel anabolic reactions.

* The balance between anabolic and catabolic pathways is crucial for maintaining homeostasis in the body.