Question

$3C{O}_2+9ATP+6NADPH+\text{Water}\to \text{glyceraldehyde}3-\text{phosphate}+9ADP+6NADP++8Pi$
Analyze the above reaction and answer the following questions:
a. How many molecules of ATP & NADPH are required to fix one molecule of $C{O}_2$?
b. Where in the chloroplast does this process occur?

Answer 1

Number of molecules of ATP

$3C{O}_2+9ATP+6NADPH+\text{Water}\to \text{glyceraldehyde}3-\text{phosphate}+9ADP+6NADP++8Pi$
From the given equation :
3 molecules of $C{O}_2$ require 9 ATP molecules.
Hence, $1C{O}_2$ molecule requires = 9/3 = 3 ATP molecules

Number of molecules of NADPH

From the given equation :
3 molecules of $C{O}_2$ require 6 NADPH molecules.
Hence, 1 $C{O}_2$ molecule requires = 6/3 = 2 NADPH molecules

Final answer

3 ATP molecules and 2 NADPH molecules

Dark reaction

$3C{O}_2+9ATP+6NADPH+\text{Water}\to \text{glyceraldehyde}3-\text{phosphate}+9ADP+6NADP++8Pi$
The above given equation is the first step of the dark reaction, that is, reduction of $C{O}_2$ .
● It requires ATP, NADPH as the energy source for the formation of product and water.
● The major product formed is glyceraldehyde -3- phosphate.

Location of dark reaction

Dark reaction occurs in the stroma of chloroplast.

Final answer

Stroma