10.3-3CC - Campbell Biology

Question

Explain why a poison that inhibits an enzyme of the Calvin cycle will also inhibit the light reactions.

Step-by-Step Solution

Answer

The poison may inhibit the productions of ADP and NADP⁺. It, in turn, stops the Calvin cycle that hinders the light reactions.

Step 1: Description of the Calvin cycle

The glucose is created from the process called the Calvin cycle. It is an important component for the growth of autotrophs. Many other organisms are dependent on autotrophs for their survival. So, the Calvin cycle is an important process for the existence of all living organisms.

Step 2: Description of the role of enzymes in the Calvin cycle

In the Calvin cycle, there are about eleven enzymes involved. The main work of enzymes is carbon fixation. The major enzyme is the Rubisco which is involved in carbon fixation. 

 

Step 3: Effect of poison on the Calvin cycle and light reactions

The Calvin cycle is the repository of ADP and NADP⁺. These components are produced in these reactions in the number of three and two, respectively. 

 

The enzyme of the Calvin cycle hindered with the poison may result in the hindrance of this cycle. It may lead to blockage in the production of ADP and NADP⁺. 

 

These are essential molecules for the progress of light reactions. These reactions utilize energy from these products, which also gets stopped. Hence, the two mechanisms, such as the Calvin cycle and light reactions, will be prevented by adding poison that affects the enzyme of the Calvin cycle.