_Y_+50
_IMG_Photorespiration.gif
On hot, dry days, <strong>C3</strong> plants partially close their stomata, and the enzyme <b>rubisco</b>
_FIG_Atmospheric_gases.gif	binds
O<sub>2</sub> in place of CO<sub>2</sub>. The carbon atoms in RuBP are released as CO<sub>2</sub>, in a
process called <b>photorespiration</b>.
However, unlike cellular respiration, <b>photorespiration</b> consumes <span class="yello">ATP</span>.