Question

A new experimental pesticide is being tested by a large agriculturalchemical company. An unfortunate side effect in plants treated withthis 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 bedirectly affected by the new pesticide?A. the synthesis of triose phosphates from 3-phosphoglycerateB. the transport of electrons along the photosynthetic electrontransport chainC. the carboxylation of RuBP by rubiscoD. the oxidation of RuBP by rubisco

Answer 1

Answer:

A: The synthesis of triose phosphate from 3-phosphoglycerate

Explanation:

The process through which plant manufacture foods using inorganic raw materials in the form of water and $CO_2$ is referred to as photosynthesis. This process/reaction can be divided into two main steps:

• The light dependent reaction
• The light independent reaction also known as the dark reaction or the Calvin cycle

The light reaction involves the cleavage of water molecules and evolution of oxygen gas. The light absorbing chlorophyll in the various plant organs converts the energy from the sun into chemical energy in the form of ATP and NADPH.

The dark reaction involves the fixation of $CO_2$ and requires the energy generated in the light dependent reaction. $CO_2$ combines with ribulose-1,5-bisphosphate (RuBP) in the presence of an enzyme known as rubsico to form a two 3 carbon compounds, 3-phosphoglycerate.

The 3-phosphoglycerate produced is then reduced using NAPH and ATP from light dependent reaction to produce triose phosphates.

Hence, if the pesticide affects plants by decreasing ATP production in the chloroplast which happens to be the site of photosynthesis in plants, it will directly affect the synthesis of triose phosphates from 3-phosphoglycerate.