Question

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in ATP production in the chloroplasts. (Interestingly, production of ATP in the mitochondria is unaffected.) Given this observation, which of the following would you expect to be DIRECTLY affected by the new pesticide?A. The synthesis of triose phosphates from 3-phosphoglycerateB. the transport of electrons along the photosynthetic electron transport chainC. the carboxylation of RuBP by rubiscoD. The oxidation of RuBP by rubisco

Answer 1

Answer:

A. The synthesis of triose phosphates from 3-phosphoglycerate

Explanation:

ATP and NADPH are produced during light-dependent reactions of photosynthesis in chloroplasts. These molecules serve as an energy source and reducing power respectively during the Calvin cycle. Calvin cycle includes fixation of carbon into 3-PGA followed by reduction of 3-PGA into glyceraldehyde 3-phosphate (a triose phosphate).

The reduction step also uses NADPH as an electron donor. Two molecules of glyceraldehyde 3-phosphate make one molecule of glucose. A reduced ATP production during light-dependent reactions in chloroplast would not allow the reduction of 3-PGA into glyceraldehyde 3-phosphate. Without the formation of triose phosphate, glucose synthesis will also reduce.