Question

In single Krebs Cycle decarboxylation takes place at ________ steps

• A. Five
• B. Four
• C. Three
• D. Two

Answer 1

Answer: (D)

In Krebs’ cycle two decarboxylations occur at following steps:
$\underset{(6-C)}{\mathrm{Oxalosuccinate}}\underset{\text{ decarboxylase}}{\overset{\text{ Oxalosuccinate}}{\to }}\underset{(5-C)}{\alpha -\text{ketoglutarate}}+C{O}_2$
$\underset{(5-C)}{\alpha -\text{ketoglutarate}}+NAD+Co-A\underset{\text{dehydrogenase}}{\overset{\alpha -\text{keto glutarate}}{\to }}$
$\underset{(4-C)}{\text{Succinyl }Co-A}+NAD{H}_2+C{O}_2$