Question

How is ATP synthesis in photosynthesis different from that of respiration?

Answer 1

Hint: Respiration and photosynthesis are the two important metabolic processes of the plant. ATP synthesis in both respiration and photosynthesis is possible by several redox reactions including oxidation and reduction reactions. Both involve exchange of gases and production of energy.

Complete answer:
Photosynthesis and respiration are two major processes by which both animals and plants can supply energy for continuing their life processes.
Respiration can be defined as the process by which living cells break down complex high energy food molecules into simple low energy molecules, releasing the energy trapped within the chemical bonds.
Photosynthesis is a process that converts light energy from the sun into organic compounds by using water from soil and carbon dioxide from the air in presence of chlorophyll.
In photosynthesis, the radiant energy of the sun is converted into chemical energy. It is bound in the chemical bonds of the carbohydrates. In respiration, the carbohydrates are oxidised through a series of reactions and the energy released is trapped in ATP molecules.
Comparison between ATP synthesis in Respiration and Photosynthesis are as follows:

Respiration	Photosynthesis
-Respiration is a catabolic process.	-Respiration is an anabolic process
-It occurs in all the living cells.	-It occurs only in the chlorophyll containing cells.
-The energy locked in carbohydrates and other respiratory substrates is trapped in the ATP molecules on oxidation. Besides, some energy is also lost in the form of heat.	-The light energy is converted into chemical energy (in the form of carbohydrate)
-Oxidation of carbohydrates yields ATP.	-ATP is formed by the conversation of light energy (photophosphorylation).
-ATP synthesized is utilized in various metabolic processes.	-ATP formed is utilized in the dark reaction of photosynthesis.
-The raw materials are oxygen and carbohydrates.	-The raw materials are carbon dioxide and water
-Glycolysis occurs in the cytoplasm and oxidation of pyruvic acid occurs within mitochondria	-Reactions of photosynthesis occur within chloroplast.

Note: Respiration and photosynthesis are the two most important processes responsible for ATP synthesis or production of energy. They may be considered as a mirror image of each other. Respiration uses a glucose molecule and combines it with oxygen; and the result is energy released in the form of ATP, whereas in photosynthesis water and carbon dioxide combine with water and the end result is glucose.