Question

6. Which answer choices are true about photorespiration? Select all that apply. Photorespiration increases the efficiency of photosynthesis. It happens because 3-phosphoglycerate cannot be reduced to form triose phosphate sugars. It happens because there is so much more CO2 in the atmosphere than 02. It happens because rubisco can add either O or Co, to RuBP. CO2 and ATP are produced. ATP is consumed by photorespiration.

Answer 1

Photorespiration is a wasteful process that reduce the efficiency of photorespiration. Rubisco can react with either CO2 or O2. When low CO2:O2 ratio and high temperature rubisco react with O2 instead of Co2 and produce three-carbon compound, 3-PGA, and a two-carbon compound, phosphoglycolate. Phosphoglycolate is not in calvin cycle. During this process energy is consumed but all the products are not useful to form glucose.

so the statement one is incorrect.  Photorespiration reduce the Efficiency of photosynthesis.statement 2 is also wrong. because during  Photorespiration 3-PGA is formed which can be converted into trios phosphate. but other prosuct of photorespiration phosphoglycolate cannot enter the calvin cycle. photo respiration happens when there is low CO2:O2 ratio ie there is more O2 than CO2 in atmosphere. so statement 3 is also wrong. statement 4 is true because Rubisco can react with either CO2 or O2. the final product of photorespiration is CO2 but not ATP. so statement 5 is also wrong. statement 6 is true because during photorespiration ATP is used. so statements 4 and 6 are true