During photorespiration, the phosphoglycolate (PGO) produced by RuBP oxygenation is eventually converted to phosphoglycerate (PGA); 75% of the carbon in PGO is recovered. How many molecules of PGO are required to generate two molecules of PGA through this route

4

Explanation:

1. Photorespiration occurs in plants and it is a wasteful pathway, it competes with the Calvin cycle. It begins when rubisco (Ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) catalyzes both CO2 and O2 fixation) acts on O₂ instead of CO₂.

2. Photorespiration is initiated by the oxygenase activity of rubisco, the same enzyme that is also responsible for CO2 fixation.

3. Phosphoglycolate formed by O₂ fixation is recycled to the Calvin cycle intermediate phosphoglycerate in the photorespiratory pathway.

4. During oxygen fixation,1 molecule of PGA and 1 molecule of 2-phosphoglycolate are formed. The 2-phosphoglycolate  is converted back to PGA in the photorespiratory cycle.

the catch is that the top numbers are atomic masses the bottom numbers are the numbers of protons and electrons in an uncharged atom. they are the number of that atoms as you would find them on the periodic table. further, the numbers on the left are used to determine the missing numbers on the right

so here we go

atomic mass

239 + 1 = y + 134 + 3 combine like terms

240 = y + 137             subtract 137 from both terms

240 - 137 = y

103 = y

atomic number

94 = z +54 + 0

94 = z + 54               subtract 54 from both sides.

40 = z

answer

2licl + 3o2 i yook the test and it was correct.