How are photosynthesis and respiration related to each other?

 

 
Photosynthesis and respiration are related, as in both mechanisms, the plants gain energy.
 
In photosynthesis, plants gain energy from solar radiations whereas, in respiration, they break down glucose molecule to get energy in the form of ATP molecules.
 
They are related also because they are dependent on each other. The product of doing photosynthesis  i.e., glucose (food) is utilised in respiration to yield energy (ATP). Which doing so, it releases many other simple molecules (CO2 +H2O) whcih are utilised in photosynthesis to produce more sugers.