Similarities and differences between photosynthesis and respiration?

Simple answer -

In photosynthesis ATP is used to reduce carbon dioxide to glucose.

In respiration glucose is oxidized to produce carbon dioxide and ATP.

Things they have in common include ATP, glucose, and carbon dioxide.


Edit- Steven's answer makes me fearful for the outlook of our science education in this country...

"The main difference between photosynthesis and respiration is where it occurs"
No, the main difference is that photosynthesis uses photons to synthesize glucose and respiration consumes glucose to produce ATP.

"one being in plants and some bacteria and the other being in most every other living thing."

There are many organisms that don't respire.

"The other difference is that plants require sunlight for the process to occur, whereas respiration does not."

There are hundreds of other differences...photosynthesis and cellular respiration are two very complex metabolic pathways each requiring dozens of different enzymes and substrates to proceed.

"But there is an important mutual relationship between the two processes because of the ingredients required, and bi-products produced. If plants take carbon dioxide and expel oxygen, and most other living things take in oxygen and expel carbon dioxide, the importance of both systems working in unison is obvious."

It's beneficial, yes, but not necessary - there are organisms which respire but don't need oxygen, so it wouldn't matter if there were no photosynthetic organisms producing oxygen.  Also, photosynthetic organisms are autotrophs which don't necessarily depend on the existence of respiring organisms.


"Both photosynthesis and cellular respiration transform energy. Photosynthesis transforms the energy of sunlight into glucose in two phases: the light reaction and the Calvin Cycle."

These are both true statements (though the first is true for any metabolic process).

"In cellular respiration, glucose transforms into ATP for use by the cell in two phases: glycolysis and the oxidation of pyruvic acid."

No, you left out the all-important Krebs cycle.

The main difference between photosynthesis and respiration is where it occurs, one being in plants and some bacteria and the other being in most every other living thing. The other difference is that plants require sunlight for the process to occur, whereas respiration does not. But there is an important mutual relationship between the two processes because of the ingredients required, and bi-products produced. If plants take carbon dioxide and expel oxygen, and most other living things take in oxygen and expel carbon dioxide, the importance of both systems working in unison is obvious.
Both photosynthesis and cellular respiration transform energy. Photosynthesis transforms the energy of sunlight into glucose in two phases: the light reaction and the Calvin Cycle. In cellular respiration, glucose transforms into ATP for use by the cell in two phases: glycolysis and the oxidation of pyruvic acid.