91Ó°ÊÓ

We are given the equations and we have to find out whether succinic acid is oxidized or a reduced

In citric cycle the reaction is,

$C_4{H}_6{O}_4→C_4{H}_4{O}_4+2H$

and in this number of atoms of carbon and oxygen does not change during the reaction but number of hydrogen reduced by two and the reaction in which the number of hydrogen atoms decreases on the product side is termed as oxidation reaction.

Hence, the succinic acid is oxidized.

We are given the equations and we have to find out whether FAD is oxidized or a reduced.

The coenzyme reaction is,

$\mathrm{FAD}+2\mathrm{H}→{\mathrm{FADH}}_2$

and in this whole molecular formula but two hydrogen get add in it and the reaction in which the number of hydrogen atoms increases on the product side is termed as reduced reaction.

Hence, FAD is reduced in this reaction.

We are given with two equations and we have to find out the reason that why they always occur together.

In the reaction succinic acid is oxidized, which forms four-carbon molecule two hydrogen atoms are released and that hydrogen atoms are taken by the enzyme called $FAD$and gets reduced So, in order to utilize the hydrogen it is necessary that these reactions occur together otherwise hydrogen will be an obstacle in further reactions.