Tutoring biology, or any subject, essential concepts can continue to deliver surprises. The tutor looks at cell theory.

Cell theory is perhaps the first brick in the structure of modern biological understanding. It states the following:

1. Every living organism is made of cells.
2. There is no smaller unit of life than the cell.
3. Cells can only arise from other living cells.

A modern inclusion to the cell theory is the following:

• In the context of a living organism, its energy consumption happens within cells.

The last idea is perhaps a little more surprising than the others. For instance, it suggests that the heat constantly radiating from a large mammal like a human being is evolved from the individual metabolic activities within its cells. No energy is consumed in the fluid of the blood or the tissue fluid, but only by the surrounding cells.

Ultimately, of course, the energy consumed by a cell is transformed to ATP in its mitochondria. Since mitochondria only exist within cells (as far as I’m aware, anyhow), the idea makes perfect sense.

Source:

thoughtco.com

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.