Question

Write the difference between light reaction and dark reaction.

Answer 1

Hint: They are the processes that occur during the process of photosynthesis where one utilizes light energy while the other releases it. Both the process functions opposite to each other and are part of photosynthesis.

Complete answer:
Photosynthesis comprises of two phases:
-The light-dependent phase or photochemical phase is commonly called a light reaction.
-Biosynthetic phase or dark phase. It is a light-independent phase.

Difference between light reaction and dark reaction

Light reaction	Dark reaction
It takes place in the presence of light.	It takes place in the presence or absence of light.
It is also called a photochemical reaction or Hill reaction.	It is also called the biosynthetic phase or Blackman's reaction or carbon dioxide fixation or the Calvin cycle.
It is a photochemical phase.	It is a biochemical phase.
It occurs in the thylakoid membranes of grana and stroma lamellae.	It occurs in the stroma of the chloroplast.
Photolysis occurs in Photosystem II.	Photolysis occurs in Photosystem I.
It involves the absorption of light energy and its conversion into chemical energy in the form of ATP and NADPH and hydrogen ions.	It utilizes ATP and NADPH 2 for the fixation of carbon dioxide to form carbohydrates, mainly glucose.
The water molecule splits into hydrogen and oxygen.	Glucose is produced, carbon dioxide is utilized in the dark reaction.
It is simply the process of the production of organic energy molecules.	It is the process of utilizing organic energy molecules.

Note: In 1779, Colin Flannery introduced the idea of light used in the process of photosynthesis. The other sugars such as glucose, starch, and cellulose which are three-carbon sugars are mainly produced by the functioning of the Calvin cycle, and these sugars are used by plants as a structural building material. It was discovered by scientists Melvin Calvin, James Bassham, and Andrew Benson in 1950.