Similarities ...

→ Both involve in production of energy

→ Both involve the exchange of gases

→ Both the process takes place in cell organelle which was considered as endosymbiotic organism. They are chloroplast and Mitochondria, Photosynthesis takes place in Chloroplast where as respiration takes place in mitochondria.

→ At critical condition both have alternate pathway.

Differences...

→Photosynthesis takes place in chloroplast, where as respiration takes place in mitochondria.

→Photosynthesis involve production of carbohydrate and respiration involve breaking of carbohydrate.

→ Photosynthesis occur only during presence of sunlight where as respiration occurs all the time.

→ In photosynthesis process Oxygen is released where as in respiration Oxygen is utilised.

These are the main differences between Photosynthesis and respiration.

Cellular respiration and photosynthesis are the two major processes by which animal and plant cells supply themselves with energy to carry out their life processes.  They may be thought of as mirror images of each other; together they represent a "win-win" situation in the game of life.  Cellular respiration takes a glucose molecule and combines it with oxygen; the result is energy in the form of ATP, along with carbon dioxide and water as waste products.  Photosynthesis takes carbon dioxide and combines it with water, enabled by radiant energy, usually from the sun.  The end result is glucose, with oxygen being the waste product.  The two processes are similar in that they both produce energy, albeit in two different forms.  They are different in that photosynthesis assembles the glucose molecule, while cellular respiration takes it apart.  The win-win of the two processes is that they both provide each other with the necessary ingredients for the process to take place:  glucose and oxygen for cellular respiration, carbon dioxide and water for photosynthesis.

Photosynthesis                                       Respiration

-Occurs in plants only                            - Plants and animals

-CO2 + H2O  = Sugars + O2                  - Sugars + O2 = CO2 + H2O

-needs the energy coming from light       - Acquire energy from                        

                                                               chemical reaction alone

-organisms of which are self sustaining    - they are dependent on

thus they create theri own food                 the products of

                                                              photosynthesis

                                                              organisms

Oxygen is their by product                      -Carbon dioxide is their 

                                                              by-product

needs energy                                          produces energy