ul ose ▁( L - ▁and ▁D - form ). ▁Again , ▁only ▁the ▁D ▁en anti omer ▁is ▁naturally ▁occurr ing . ▁ ▁Bi ological ▁Function s ▁ ▁There ▁are ▁a ▁few ▁known ▁ways ▁that ▁t et rose ▁sug ars ▁are ▁used ▁in ▁nature . ▁Some ▁are ▁seen ▁in ▁met abol ic ▁path ways ▁and ▁others ▁are ▁known ▁to ▁affect ▁certain ▁en zym es . ▁ ▁Inter medi ates ▁in ▁the ▁Pent ose ▁Ph osph ate ▁Path way ▁ ▁One ▁of ▁the ▁met abol ic ▁path ways ▁that ▁a ▁t et rose ▁is ▁involved ▁in ▁is ▁the ▁Pent ose ▁Ph osph ate ▁Path way . ▁In ▁the ▁Pent ose ▁Ph osph ate ▁Path way , ▁there ▁is ▁an ▁ox id ative ▁stage ▁and ▁a ▁non - ox id ative ▁stage . ▁A ▁t et rose ▁sugar , ▁D - ery th rose , ▁is ▁util ized ▁in ▁the ▁non - ox id ative ▁stage , ▁where ▁D - rib ul ose ▁ 5 - ph osph ate ▁is ▁generated ▁into ▁a ▁ 6 ▁carbon ▁sugar ▁( f ruct ose ▁ 6 - ph osph ate ) ▁and ▁a ▁ 3 ▁carbon ▁sugar ▁( gly cer al de hy de ▁ 3 - ph osph ate ). ▁Both ▁of ▁these ▁mole cules ▁can ▁be ▁used ▁elsewhere ▁in ▁the ▁body . ▁ ▁D - ery th rose ▁ 4 - ph osph ate ▁is ▁generated ▁as ▁a ▁product ▁of ▁a ▁reaction ▁called ▁trans ald olation . ▁In ▁the ▁Pent ose ▁Ph osph ate ▁Path