Question

The dark reaction of photosynthesis take place in
A.Stroma
B.Grana
C.Cytoplasm
D.None of the above

Answer 1

Hint: The dark reaction is also known as carbon assimilation reaction. In this reaction the inorganic form of carbon is converted to organic form in organelle known as chloroplasts.

Complete step by step answer:
Photosynthesis takes place in two major steps.
-Light reaction and the dark reaction.
ATP and NADPH is formed during the light reaction. Which is utilised for the fixation of carbon in the dark reaction. Carbon fixing during the dark reaction which is the light independent process takes place in the stroma of the chloroplast.
The light reactions of photosynthesis occur in the thylakoid grana present in the chloroplast.
-Dark reaction is also known as Calvin cycle or light independent reactions.
Dark reactions of photosynthesis are the chemical reactions that convert carbon dioxide and other compounds into glucose. These reactions occur in the stroma. Stroma is a fluid filled area of a chloroplast outside the thylakoid membrane. These reactions take the products ATP and NADPH of light dependent reaction and perform further chemical processes on them.
The Calvin cycle uses the reducing power of ATP and NADPH of the light reaction to produce sugar for the plants to use. There is no direct reaction to convert carbon into sugar but there are series of reactions that are called Calvin Cycle.
Structure of chloroplasts-

Hence option A is correct.

Note:
There are three steps in the Calvin cycle: carbon fixation, reduction reaction, ribulose 1,5-bisphosphate regeneration.
Six turns of the Calvin cycle are required for the production of one molecule of glucose.