During photorespiration in Peroxisome, two molecules of glycine ($2H_{2}NCH_{2} - CO_{2}$) are transferred into mitochondrion, where they are converted into one molecule of serine ($HOCH_{2} - H_{2}NCH - CO_{2}$). Thus, the ratio between 2C and 3C intermediates having $–NH_{2}$ group is 2:1.