QTB Team Details

Topic of bachelor thesis: Isotope-labelled modeling of the Calvin-Benson-Bassham cycle

Although the Calvin-Benson-Bassham cycle was already proposed in 1954, it is still the subject of intense research. The controversy about the cycle’s structure was fuelled by the findings of Gibbs and Kandler in 1956 and 1957, when they observed that radioactive 14CO₂ was dynamically incorporated in hexoses in a very atypical and asymmetrical way, a phenomenon later termed the ‘photosynthetic Gibbs effect’. Now, it is widely accepted that the photosynthetic Gibbs effect is not in contradiction to the reaction scheme proposed by CBB, but the arguments given have been largely qualitative and hand-waving. With this work we present the, to the best of our knowledge, first quantitative examination of the photosynthetic Gibbs effect. Using our model findings, we can show, that some of the asymmetries measured by Gibbs are in fact emergent phenomena of the CBB cycle structure [publication pending].