Question

Choose the correct statement:

• A. Reduction of NAD to NADH to occurs in Calvin Cycle.
• B. S. Ochoa showed ${\mathrm{NADP}}^{+}$ is the biological electron acceptor in the chloroplast.
  
• C. Fixation and reduction of carbon dioxide requires ATP, NADPH and light.
• D. NADH produced in light reaction is used for reduction of carbon dioxide.

Answer 1

The correct option is B S. Ochoa showed ${\mathrm{NADP}}^{+}$ is the biological electron acceptor in the chloroplast.


Light reaction in photosynthesis produces ATP and reduces ${\mathrm{NADP}}^{+}$ to NADPH.

Robert Hill showed that when isolated chloroplast was illuminated with light, it could only produce oxygen if any suitable electron acceptor is present.

Later on, S. Ochoa showed that ${\mathrm{NADP}}^{+}$ is the biological electron acceptor in the chloroplast. NADPH gets oxidised by donating its electron in the Calvin cycle.

Calvin cycle is the carbon fixation phase where ${\mathrm{CO}}_2$ is reduced using NADPH and ATP. This phase doesn't require light and hence, is called a dark reaction.