The primary source of energy for cells to grow and divide is ATP (adenosine triphosphate). ATP is a molecule that acts like a cellular energy currency.

Here's how it works:

* Cellular Respiration: Cells obtain energy from the breakdown of food molecules like glucose through a process called cellular respiration.

* ATP Production: Cellular respiration produces ATP, which stores energy in its chemical bonds.

* Energy for Growth and Division: When cells need energy for processes like growth, division, protein synthesis, and active transport, they break down ATP, releasing the stored energy.

In summary, cells obtain energy for growth and division by breaking down food molecules through cellular respiration to produce ATP, which acts as a cellular energy currency.