PHOTOSYNTHESIS
PHOTORESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A plant toxin is produced.
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A ‘useless’ product is produced.
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A ‘harmful to humans’ form of glucose is produced.
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Detailed explanation-1: -Photorespiration is harmful to C3 plants because it reduces plant productivity, which is why it is also known as a wasteful process. Many higher plants use photorespiration as a means of respiration.
Detailed explanation-2: -Photorespiration has appeared to be downright wasteful because it virtually undoes much of the work of photosynthesis by converting sugars in the plant back into carbon dioxide, water and energy.
Detailed explanation-3: -Photorespiration is a metabolic pathway that occurs in photosynthetic organisms and releases carbon dioxide, consumes oxygen, and produces no chemical energy or food. This process limits the growth rates of plants.
Detailed explanation-4: -Photorespiration reduces net photosynthesis in two ways. First, there is a competition between O2 and CO2 for the active site of rubisco. Those active sites that take up O2 cannot take up CO2. Second, there is the release of CO2 in the PCO cycle.