# What is the relationship between photosynthesis and cellular respiration?

Sep 8, 2016

Photosynthesis makes the glucose that cellular respiration uses to make ATP.

#### Explanation:

Plants are autotrophs , meaning that they make their own food from inorganic substances and sunlight = photosynthesis.

Photosynthesis :
- $\textcolor{red}{\text{Input}}$: water, $C {O}_{2}$ and sunlight
- $\textcolor{g r e e n}{\text{Output}}$: glucose and ${O}_{2}$.

This glucose is food for the plant, but is not yet usable energy. Cells of plants use mainly the molecule ATP (adenosine triphosphate) as energy.

Cellular respiration:
- $\textcolor{red}{\text{Input}}$: glucose and ${O}_{2}$
- $\textcolor{g r e e n}{\text{Output}}$: $C {O}_{2}$, water and ATP (energy).

So you can see that (part of) the output of photosynthesis is the input of cellular respiration and vice versa (see image). Note that they are still separate processes that are not physically linked.