Lesson 3 of 8

Lesson 3: Cellular Energy, Photosynthesis and Respiration

Living things run on energy. Plants capture energy from the sun, and almost all living things release that stored energy to power their cells. The energy currency of the cell is called ATP.

Photosynthesis

Photosynthesis happens in the chloroplasts of plants. It takes in light energy and turns it into stored sugar.

REMEMBER

Photosynthesis: carbon dioxide plus water plus light energy gives glucose (sugar) plus oxygen.

Cellular Respiration

Cellular respiration happens in the mitochondria of nearly all cells. It breaks down sugar to release usable energy.

REMEMBER

Cellular respiration: glucose plus oxygen gives carbon dioxide plus water plus energy (ATP).

Notice that these two are opposites. The products of one are the reactants of the other. That cycle keeps oxygen and carbon dioxide balanced on Earth.

Coach Fite

That mitochondria is the engine room, the power plant. No fuel, no motor running, no fourth quarter. Feed your body right and your engine keeps firing when the other guy is gassed.