Im currently in 11th grade and have biology as one of my subjects. We were taught about krebs cycle ofcourse not in depth but i was really confused in one step. We know that gdp is produced during krebs cycle. My teacher told me gdp is converted to gtp and broken down to gdp to make atp. My question is that why is gdp converted to gto in the first place if in the end gdp is used to make atp?