Here's why:

* Energy: Cell growth and division are complex processes that require a significant amount of energy. This energy is typically provided by ATP (adenosine triphosphate), which is the primary energy currency of cells.

* Building Blocks: New cells are constructed from a variety of molecules, including:

* Proteins: These are the workhorses of the cell, responsible for a wide range of functions. They are made from amino acids.

* Lipids: These are fats and oils that make up cell membranes and other structures.

* Carbohydrates: These are sugars that provide energy and contribute to cell structure.

* Nucleic acids: These include DNA and RNA, which carry genetic information and are essential for cell function.

In summary, building new cells requires both the energy to power the process and the raw materials to create the cell's components.